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Car Forum / Driving, Maintenance, Tuning / Maintenance and Repair / March 2007Spongy Brakes - Air - Bleeding - How to tell?
Hello. I've been up and down different info resources online and even to a mech or two. So, here's what I need to know: Let's say the mech has checked everything in the brake system and had found nothing wrong. BUT, the brakes are spongy and the pedal needs to be depressed all the way for a complete stop. Worse during slow driving and stopping than anything else. How else apart from actually driving the car can the Mech come to the conclusion that the brake line has to be bled? (eg, there's air in there?). I'd truly appreciate any input regarding this. Thanks in advance. Find a mechanic that knows what he is doing. The one you are talking to apparently doesn't. > Hello. I've been up and down different info resources online and even to a > mech or two. So, here's what I need to know: [quoted text clipped - 10 lines] > > I'd truly appreciate any input regarding this. Thanks in advance. >> Hello. I've been up and down different info resources online and even to >> a mech or two. So, here's what I need to know: [quoted text clipped - 13 lines] > Find a mechanic that knows what he is doing. The one you are talking to > apparently doesn't. Hehe, that was the point of my coming online here. Because I'm coming across too many idiots who don't know, or are money hungry crooks, or whatever else. The story of my life! The Point mind you is that everyone everywhere says that most likely the car needs to be bled. But this guy at one spot is telling me that they checked everything and there's nothing wrong. BUT THEY DIDN'T DRIVE THE DARN CAR. And another place I haven't been to yet is quoting me lots of money because he claims that bleeding it requires a heck of alot of work. I just need to know if it's actually possible to tell that the car doesn't need bleeding just by looking into it? > Hello. I've been up and down different info resources online and even to a > mech or two. So, here's what I need to know: [quoted text clipped - 7 lines] > How else apart from actually driving the car can the Mech come to the > conclusion that the brake line has to be bled? (eg, there's air in there?). Is The question -> Can someone tell there is air in the brake system without taking it for a test drive? The answer is a definite Yes. If you are trying to ask something else then - I don't know. -jim > I'd truly appreciate any input regarding this. Thanks in advance. >Hello. I've been up and down different info resources online and even to a >mech or two. So, here's what I need to know: > >Let's say the mech has checked everything in the brake system and had found >nothing wrong. >BUT, the brakes are spongy and the pedal needs to be depressed all the way That's brakes that need to be bled if all other causes are eliminated. Now IF I knew the make and model I might be able to tell you other common causes for this condition. >for a complete stop. Worse during slow driving and stopping than anything >else. > >How else apart from actually driving the car can the Mech come to the >conclusion that the brake line has to be bled? (eg, there's air in there?). Well, he has ONE advantage over us. He knows what make and model the car is! Don www.donsautomotive.com >I'd truly appreciate any input regarding this. Thanks in advance. >>Hello. I've been up and down different info resources online and even to a >>mech or two. So, here's what I need to know: [quoted text clipped - 20 lines] > Don > www.donsautomotive.com It's a Suzuki Sidekick, '95 (4WD). 'and thank you very much for your input! >>>Hello. I've been up and down different info resources online and even to a >>>mech or two. So, here's what I need to know: [quoted text clipped - 24 lines] > >'and thank you very much for your input! Look and see if the pads are wearing tapered. Happens ALL THE TIME to Hondas -- that's why i asked make and model. Particularly if you are in salt country, the caliper slides get seized. Most of the pedal is used up bringing the unevenly worn pads into alignment with the rotor and by the times there is significant brake application your pedal is on the floor. Cure is new pads and clean and lube all caliper slide surfaces and pins. There is synthetic grease made just for this purpose. This is an important part of a brake job that never gets done atr BrakeCheck. You can check for rear drum brakes out of adjustment by setting the parking brake and seeing if the pedal improves. Don www.donsautomotive.com Don <don@NO-SPAMdonsautomotive.com> wrote in article > > Look and see if the pads are wearing tapered. Happens ALL THE TIME to > Hondas -- that's why i asked make and model. Particularly if you are [quoted text clipped - 11 lines] > Don > www.donsautomotive.com In his second post, the OP outlined the two categories in which he places automotive technicians.... ------------------------------------- "Hehe, that was the point of my coming online here. Because I'm coming across too many idiots who don't know, or are money hungry crooks, or whatever else." ------------------------------------- Since you, obviously, seem to know your way around a Honda brake system, it's safe to assume he's not placed you in the first category. Your suggestion for a cure, however, violates the shade-tree WD-40/Duct Tape theorem...."If it moves and it shouldn't, use Duct Tape. If it doesn't move and it should, use WD-40". Are you absolutely SURE he can't fix the problem he describes with a well-placed shot of WD-40 to the caliper slides?....lol!!! Isn't that all you're gonna' do.....then charge him for the work you outlined? BTW - Have you read Mitch Snider's column in this month's Brake & Front End about professional technicians actually charging what they are worth? >Hello. I've been up and down different info resources online and even to a >mech or two. So, here's what I need to know: >Let's say the mech has checked everything in the brake system and had found >nothing wrong. >BUT, the brakes are spongy and the pedal needs to be depressed all the way >for a complete stop. Worse during slow driving and stopping than anything >else. Pump the brakes a bunch of times. If they firm up and quit going to the floor then you have air in the system. Or has a bad master cylinder... >>Hello. I've been up and down different info resources online and even to a >>mech or two. So, here's what I need to know: [quoted text clipped - 8 lines] > Pump the brakes a bunch of times. If they firm up and quit going to the > floor then you have air in the system. >Or has a bad master cylinder... A bad master cylinder won't firm up; it'll keep going to the floor. >> Or has a bad master cylinder... > A bad master cylinder won't firm up; it'll keep going to the floor. when the master cylinder started leaking on my race car, it was firm, firm, floor, firm, firm, floor. And the replacement one was borked out of the box - went to bench bleed it and it was leaking past the seal. Ray >>> Or has a bad master cylinder... >> A bad master cylinder won't firm up; it'll keep going to the floor. >when the master cylinder started leaking on my race car, it was firm, >firm, floor, firm, firm, floor. Yes, and replacing the master cylinder would be a terrible diagnosis for a pedal that gets firmer with each depression. AZ Nomad Wrote: > >Or has a bad master cylinder... > A bad master cylinder won't firm up; it'll keep going to the floor. I agree, not sure if this has not already been mentioned, but you could check for a bypassing master cylinder. Pump the pedal a few times to build up pressure, and hold your foot down, if it slowly creeps lower or to the floor, you could have a defective bypassing master cylinder, where it leaks internally, with no loss of brake fluid. If so you will have to change the master cylinder. Also make sure that not only each wheel is fully bled, but also your master cylinder has no air. Master cylinders should be bench bled when installed, but you could also bleed on the vehicle, by pressurizing the brake system, and cracking open each brake line at the master cylinder, one at a time. Place a rag underneath the reservoir, and wash away any spilled fluid after your finished. Bleeding a master cylinder on a vehicle is one area that a brake pressure bleeder can really shine, as you can do it by yourself, and it can push out any stubborn air bubbles, which can be trapped and difficult to remove. A pressure brake bleeder uses an adapter to seal the master cylinder, and air to pressurize the brake system and push on the brake fluid, after which you just crack open brake lines, or bleeder screws. I usually get a great pedal when I use mine, plus clean brake fluid throughout, which is a good thing, moreso now a days, with hydraulic brake parts costing so much more than they used to.  Signaturewheelin4x4 http://www.automotiveforums.com >>Hello. I've been up and down different info resources online and even to a >>mech or two. So, here's what I need to know: [quoted text clipped - 8 lines] > Pump the brakes a bunch of times. If they firm up and quit going to the > floor then you have air in the system. uhuh! I've seen that. Did it the other day (not a bunch of times) but a coupla times and saw a difference. Don't recall how long it was before it got bad again. Mind you, the fella who's so convinced that there's nothing wrong is the one who sits up front taking in customers. He's not the mech, you know? If someone told me I had air in the brakes I would wonder just 'how' did that air get there? It can't be created, it has to have been introduced somehow. Now if you were out rock crawling or ravine climbing and the fluid in the brake master cylinder was really low or if you had it rubber side up, then air could have gotten in, otherwise.... Can you pump it up? One sign of air is the ability to pump the pedal and the pedal comes way up. If the pedal is consistently low and solid feeling, I think that the emergency brake adjuster in the rear shoes is in need of a manual adjustment or the rear shoes were worn out. If the emergency brake grabs right at the end of it's travel or doesn't grab, then I would look at the back brakes first. If the pedal holds, but sinks under your foot, the Master cylinder is bad unless there is a leak. If you hit it fast and it grabs, but when you hit it slow it sinks, I think Master. Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pictures.html?id=2115147590 (More Off Road album links at bottom of the view page) > Hello. I've been up and down different info resources online and even to a > mech or two. So, here's what I need to know: [quoted text clipped - 9 lines] > > I'd truly appreciate any input regarding this. Thanks in advance. > If someone told me I had air in the brakes I would wonder just 'how' did > that air get there? It can't be created, it has to have been introduced [quoted text clipped - 18 lines] > If you hit it fast and it grabs, but when you hit it slow it sinks, I > think Master. There's a mech down the block whom I'd trusted up until now. I had NO problems with the brakes beforehand 'cept for the meshing noise (which tells me what? Bad Brake Pads). So I take it to him and obviously he did a piss-poor job. Days later I returned the car to be bled again and I'm convinced (for reasons I won't get into) this guy did nothing, OR doesn't know what the heck he's doing. 'and so thus, I do not plan on returning there again. > If someone told me I had air in the brakes I would wonder just 'how' did > that air get there? It can't be created, it has to have been introduced > somehow. He said he just had a brake job (what that means exactly who knows) Apparently he had a scraping noise and some work was done and he no longer has the noise (at least he no longer complains of that). Now he has a new problem of a low or soft pedal. He has returned twice complaining about the problem and apparently nothing changed. So if there is air in the line that is not a big mystery. What his question is I'm not quite sure. It sound like he may have gone somewhere else and they told him it was air in the lines and he is not satisfied with that answer. -jim > Now if you were out rock crawling or ravine climbing and the fluid in > the brake master cylinder was really low or if you had it rubber side [quoted text clipped - 35 lines] > > > > I'd truly appreciate any input regarding this. Thanks in advance. >> If someone told me I had air in the brakes I would wonder just 'how' did >> that air get there? It can't be created, it has to have been introduced [quoted text clipped - 9 lines] > they told him it was air in the lines and he is not satisfied with that > answer. Hmmm, thanks jim, close but not yet. The only people who've told me it's probably air in the line are folks online of which there've been many elsewhere along with one or two folks here. Problem is I'm tired of playing darned 20 questions with this guy at the shop who probably doesn't know what he's talking about. My question was, HOW or IF its possible to see that air is NOT needed just by checking things and not actually driving the car. They're convinced there's nothing wrong with my car at all! Yet all these clowns need to do is drive it slowly around a few times to see what I'm talking about. Anyhow, I've been invited to return for them to do exactly that and probably play another set of 20 questions all over again which I'm simply feeling quite peachy about (sense the sarcasm?) N'other words, they talk to me like I'm a friggin idiot. So I thank everyone here for at least trying to help me. Next time I DO go there, I'll find my way over to the mech which I've always been able to do at this place and speak with him personally. Problems like these (of which I've had quite a few in the past) usually entail my walking in expecting the other guy (mech or whomever) to know what they're talking about. 'and so, who am I to question what they say unless I'm armed with information of my own, you know? Thus the reason for my visiting these forums to pick the minds of generous folks like yourselves. :-) probably too late for suggestions, but if the problem is worst when u are driving slow, maybe it is a leak in the booster or the master cylinder? Some brakes rely on engine vacuum, which is lower when u are cruising around slowly. If they are leaking air into the system via broken vacuum it could be possible this air is ending up in the brake lines some how > Hmmm, thanks jim, close but not yet. Ok see if this is little closer -> YOU ARE A MORON. What you are trying to do is get a particular answer without a fair hearing of the facts. You are not going to reveal what work was done on the brakes. You are not going to reveal whether the issue you are now calling a problem existed before the work was done and if that was part of the work that was agreed upon. You are not going to reveal what the mechanic's recommendation is/was. For instance, he may have told you you need back brakes done also, but you refused to have that done. Now you think you can whine about it on Usenet and somehow that it is going fix your car - what a moron. The biggest problem for any body trying to help you is since you are a moron one can't even assume there IS any thing at all wrong with your car. What is known is that the pedal feels different and you notice that most at low speed. The stopping capability of the car may have improved tenfold, but since you are a moron your not going to mention that. > The only people who've told me it's probably air in the line are folks > online of which there've been many elsewhere along with one or two folks [quoted text clipped - 9 lines] > quite peachy about (sense the sarcasm?) N'other words, they talk to me like > I'm a friggin idiot. You are a FRIGGIN IDIOT. And you are on the internet looking for other friggin idiots to support your point of view. If you want a second opinion take it to another shop the internet is no place to ask your question, because you cannot present a lucid set of facts and ask a lucid question. > So I thank everyone here for at least trying to help me. Next time I DO go > there, I'll find my way over to the mech which I've always been able to do > at this place and speak with him personally. > Problems like these (of which I've had quite a few in the past) I'll bet. > usually > entail my walking in expecting the other guy (mech or whomever) to know what > they're talking about. 'and so, who am I to question what they say unless > I'm armed with information of my own, you know? Thus the reason for my > visiting these forums to pick the minds of generous folks like yourselves. Oh OK now that you know it must be the air jumping over from the brake booster to the brake lines your all set. -jim >> Hmmm, thanks jim, close but not yet. > > Ok see if this is little closer -> YOU ARE A MORON. Hey dumbass, re-read everything that I'd written or is your own thought system too filled with air as well? > >> Hmmm, thanks jim, close but not yet. > > > > Ok see if this is little closer -> YOU ARE A MORON. > > Hey dumbass, re-read everything that I'd written or is your own thought > system too filled with air as well? You asked only one question: >I just need to know if it's actually possible to tell that the car doesn't >need bleeding just by looking into it? >How else apart from actually driving the car can the Mech come to the >conclusion that the brake line has to be bled? (eg, there's air in there?). The only answer you will accept is they have to drive the car to determine there is air in the brake lines. That's stoopid. Driving the car isn't going to tell you anything about air in the lines. It wouldn't be a bad idea to drive the car to give a general diagnosis but for answering that one single question, no it is not necessary. They obviously drove the car after doing the brake job and they obviously know about whatever it is you are whining about and they obviously have told you something. But you aren't going to present any of the facts because you are far more interested in getting the one single answer you want. If there is anything wrong with your brakes finding some idiot on Usenet to agree with you isn't going to get them fixed. You are to dumb to realize that maybe if you presented all the details in a factual manner you might actually get an answer that works in your favor (or at the very least keeps you from wrapping your car around a big oak tree). The answer to your question is yes if all you want to know is is there air in the lines all you have to do is get in the car and pump the brakes. The reason you can tell the difference between air in the lines and the various other problems that would cause a low pedal is because air is the only thing in the brake system that is truly compressible (well, there are other things that have small amount of give but nothing even close to air for compressibility). As a result, if there where air in the line it takes more brake fluid pushed out of the master cylinder to compress that air, and consequently it takes more time for the fluid to return to the brake reservoir. Someone with experience can tell the difference between air in the lines and the various other possible problems that would cause a low pedal that pumps up. -jim and you're too much of a friggin j.rkoff to realise that the more you insult a person the more you'll be thought of as a LOSER! ....and no! They did not drive my car. I mentioned that! ....and no! I'm not looking for anyone to agree with anything I have to say! I'm only looking to see if the guy at the front desk WHO IS NOT THE MECH (I mentioned that as well) knows what the heck he's talking about! He's almost reluctant to bleed my system based on the actual mech's findings WHO ONLY went by the very little information he got from this guy at the front desk. 'And how do I know that? I WAS THERE! Again, re-read and maybe that thick brain of yours will jar into working order. end of story! >> >> Hmmm, thanks jim, close but not yet. >> > [quoted text clipped - 40 lines] > difference between air in the lines and the various other possible > problems that would cause a low pedal that pumps up. I had just purchased a car that had a spongy brake like you describe, and the mech at the dealer said "they all are like that, get used to it". So, I drove the car like that for a few years and had to replace the front calipers myself and after bleeding the brakes - holycow! The car suddenly had a firm pedal and brakes that would stop a tractor trailer! Moral of story - you can't trust mechanics all the time. Your vehicle is not one of them, but some newer models have ABS that greatly complicates getting air out of the system if lines are replaced or similar large repairs. Some have tedious procedures for bleeding that many folks would probably screw up. My van had out-of adjustment rear brake shoes when I got it (too much space between the drum and shoe), and until I adjusted it properly, the pedal would sink to towards the floor and it would only stop with the front brakes. You could possibly have this. Your little 4x4 is so light, it should stop on a dime. Good luck. Brakes are really pretty simple. > I had just purchased a car that had a spongy brake like you describe, > and the mech at the dealer said "they all are like that, get used to > it". So, I drove the car like that for a few years and had to replace > the front calipers myself and after bleeding the brakes - holycow! The > car suddenly had a firm pedal and brakes that would stop a tractor > trailer! Moral of story - you can't trust mechanics all the time. That doesn't mean it had air in the system. It could just be the calipers had to move farther due to the difference in compliance of the pad material or due to uneven wear on the pads or other causes. If there was air in the lines you would think you would have very quickly figured out that hitting the brakes twice (or more) would greatly improve the stopping capability. I mean think about situations come up all the time in city driving where you need to apply, release, apply the brakes in rapid succession. A couple hours of city driving and just about anybody would learn that pumping the brakes improves the braking capability. Although the designed firmness of the brake pedal varies a great deal from one type of vehicle to another, there are no vehicles that require pumping the brakes by design. That is, none of them are like that. -jim > Your vehicle is not one of them, but some newer models have ABS that > greatly complicates getting air out of the system if lines are replaced [quoted text clipped - 8 lines] > Your little 4x4 is so light, it should stop on a dime. Good luck. > Brakes are really pretty simple. Air in the system or moisture in the brake fluid will give problems. That is why it is best to change brake fluid ever so often. It can draw moisture and boil into steam and is as bad as air in there. Also old brake fluid gets strong and is hard on all brake rubber parts. If you are not sure about the condition of brake fluid or air in the system. Have it pressure bleed and new brake fluid added. Your brakes will love you for the new fresh fluid. MT SignatureMT-2500 http://www.automotiveforums.com > Air in the system or moisture in the brake fluid will give problems. > That is why it is best to change brake fluid ever so often. > It can draw moisture and boil into steam and is as bad as air in there. > Also old brake fluid gets strong and is hard on all brake rubber parts. Old brake fluid is pretty hard on metal parts, also. Acids will form that pit master and wheel cylinders and cause leaks in brake lines. Flushing out the old brake fluid is certainly a good idea after a few years. -jim > If you are not sure about the condition of brake fluid or air in the > system. [quoted text clipped - 9 lines] > > http://www.automotiveforums.com > If there was air in the lines you would think you would have very quickly > figured out that hitting the brakes twice (or more) would greatly improve > the stopping capability. I mean think about situations come up all the > time in city driving where you need to apply, release, apply the brakes in > rapid succession. A couple hours of city driving and just about anybody > would learn that pumping the brakes improves the braking capability. I'd sure like to know why that is. I'm also curious as to why it's more pronounced on some cars than on others, even on similar models; my '89 Grand Marquis does that more than my '91 GM. (Both have new brake fluid.) SignatureNazi: a person who is winning an argument with a liberal. > > If there was air in the lines you would think you would have very quickly > > figured out that hitting the brakes twice (or more) would greatly improve [quoted text clipped - 4 lines] > > I'd sure like to know why that is. You would like to know why what is? Does pumping the brakes improve the braking capability of your cars? It isn't supposed to. If that is your question then the 2 most likely causes are out of adjustment rear brakes and/or air in the lines. -jim >I'm also curious as to why it's more > pronounced on some cars than on others, even on similar models; my '89 > Grand Marquis does that more than my '91 GM. (Both have new brake fluid.) > -- > Nazi: a person who is winning an argument with a liberal. >> > If there was air in the lines you would think you would have very quickly >> > figured out that hitting the brakes twice (or more) would greatly improve [quoted text clipped - 10 lines] > isn't supposed to. If that is your question then the 2 most likely > causes are out of adjustment rear brakes and/or air in the lines. It sounded like you were saying this is normal in the first quote. Anyway, they don't improve a great deal, but it is noticeable. Rear brakes are adjusted fine, and brake fluid is new and as air-free as I can make it. No ABS so no fancy bleeding procedures involved. And again, I've noticed this on every car I've driven; again, it's not a pronounced effect, but it's noticeable. The pedal also firms up a little on the second or third push. SignatureNazi: a person who is winning an argument with a liberal. > >> > If there was air in the lines you would think you would have very quickly > >> > figured out that hitting the brakes twice (or more) would greatly improve [quoted text clipped - 15 lines] > adjusted fine, and brake fluid is new and as air-free as I can make it. > No ABS so no fancy bleeding procedures involved. In general if everything in the brake system is working as it was designed to work the brake fluid that gets pushed out of the MC should return back to the MC at least as fast as the pedal returns. So what you describe indicates a problem - particularly if you notice the bakes stop the car better (on dry pavement) when pumped. > And again, I've noticed this on every car I've driven; again, it's not > a pronounced effect, but it's noticeable. The pedal also firms up a little > on the second or third push. Is this with the car running or after you have turned it off? -jim > -- > Nazi: a person who is winning an argument with a liberal. >> It sounded like you were saying this is normal in the first quote. Anyway, >> they don't improve a great deal, but it is noticeable. Rear brakes are [quoted text clipped - 6 lines] > describe indicates a problem - particularly if you notice the bakes stop > the car better (on dry pavement) when pumped. It isn't so much that they stop the car better as it is that the pedal has a firmer feel and seems to give better control. The brakes on my '89 need a little work soon, but those on my '91 are outstanding since I changed the brake fluid; yet the pedal gets a tad firmer and more precise with a pump or two. >> And again, I've noticed this on every car I've driven; again, it's not >> a pronounced effect, but it's noticeable. The pedal also firms up a little >> on the second or third push. > > Is this with the car running or after you have turned it off? Running. SignatureNazi: a person who is winning an argument with a liberal. jim <"sjedgingN0sp"@m@mwt.net> wrote in article <1167571126_8761@sp6iad.superfeed.net>... > In general if everything in the brake system is working as it was > designed to work the brake fluid that gets pushed out of the MC should > return back to the MC at least as fast as the pedal returns. So what you > describe indicates a problem - particularly if you notice the bakes stop > the car better (on dry pavement) when pumped. Actually, if you look down into a master cylinder, you will see two ports at the bottom of each reservoir. The larger one is called the "filler" port while the smaller one is known as the "compensating" port. The filler port is behind the master cylinder piston seal when it is at rest while the compensating port is ahead of it. When you apply the brake pedal, the piston seal moves past the compensating port, seals the system off, and pressure builds. When you release the brake pedal, the fluid that is behind the cup in the master cylinder from the filler port unseats it, and the fluid passes to the front-side of the seal. Apply the brake again quickly, and there is more fluid ahead of the piston than before. That is why you can "pump-up" brakes. You are adding more fluid to compensate for the air that is being compressed. When you release the brakes fully, the excess fluid then returns to the reservoir slowly via the compensating port. Fluid CAN, indeed, enter the cylinder faster through the larger filler port and around the piston seal than it can return via the much smaller compensating port in front of the piston seal.......which is absolutely normal. > jim <"sjedgingN0sp"@m@mwt.net> wrote in article > <1167571126_8761@sp6iad.superfeed.net>... [quoted text clipped - 20 lines] > master cylinder from the filler port unseats it, and the fluid passes to > the front-side of the seal. No this does not happen always. It only when when the pressure in front of the seal is less than the pressure behind. That will not be the case if the system is working as designed. > Apply the brake again quickly, and there is more fluid ahead of the piston > than before. > > That is why you can "pump-up" brakes. You are adding more fluid to > compensate for the air that is being compressed. There isn't supposed to be any air. The system is designed to only push out so much fluid when everything is operating properly. That amount of fluid will maintain pressure and return fast enough so that the pedal return does not draw any additional fluid past the seal. This will only be true if everything is working as designed. -jim > When you release the brakes fully, the excess fluid then returns to the > reservoir slowly via the compensating port. > Fluid CAN, indeed, enter the cylinder faster through the larger filler port > and around the piston seal than it can return via the much smaller > compensating port in front of the piston seal.......which is absolutely > normal. jim <"sjedgingN0sp"@m@mwt.net> wrote in article <1167667990_16065@sp6iad.superfeed.net>... > > jim <"sjedgingN0sp"@m@mwt.net> wrote in article > > <1167571126_8761@sp6iad.superfeed.net>... [quoted text clipped - 24 lines] > of the seal is less than the pressure behind. That will not be the case > if the system is working as designed. If you are releasing the brake pedal, and the piston is traveling AWAY from the wheel cylinder side of things, then there WILL be a pressure differential with the pressure on the wheel cylinder side of the seal being less. > > Apply the brake again quickly, and there is more fluid ahead of the piston > > than before. [quoted text clipped - 4 lines] > There isn't supposed to be any air. The system is designed to only push > out so much fluid when everything is operating properly. Even if there is no air in the system, pumping WILL flow MORE fluid into the system to compensate for mis-adjusted drum brake shoes, or a mechanical condition that is, somehow, keeping the brake shoes from moving within their designed parameters. > That amount of > fluid will maintain pressure and return fast enough so that the pedal > return does not draw any additional fluid past the seal. Have you looked into a master cylinder as I suggested? It doesn't take a rocket scientist to observe that the filler port can certainly feed fluid a LOT quicker than the compensating port can return it to the reservoir. > This will only > be true if everything is working as designed. I suggest you pick up one of the better automotive textbooks such as those by WIlliam Crouse and/or Goodheardt-Wilcox and study about how a brake hydraulic system actually works. > > There isn't supposed to be any air. The system is designed to only push > > out so much fluid when everything is operating properly. [quoted text clipped - 3 lines] > condition that is, somehow, keeping the brake shoes from moving within > their designed parameters. A system that has mis-adjusted brake shoes is one that is not "operating properly" therefore it was specifically excluded from what was being described. Please try to pay attention. > > That amount of > > fluid will maintain pressure and return fast enough so that the pedal > > return does not draw any additional fluid past the seal. > > Have you looked into a master cylinder as I suggested? I don't have a master cylinder that needs to be looked at or a brake system that is not working properly. ++++++++++++++ Please try to pay attention ++++++++++++++++ I was describing a brake system that is in perfect working condition. A system that is working properly will not pump up. If you have brakes that firm up when pumped you are the one with the brake system that is not operating correctly. I can pump my brakes all day and the pedal stays the same height. -jim > It doesn't take a rocket scientist to observe that the filler port can > certainly feed fluid a LOT quicker than the compensating port can return it [quoted text clipped - 6 lines] > by WIlliam Crouse and/or Goodheardt-Wilcox and study about how a brake > hydraulic system actually works. I'm sure you can find an automotive textbook at the library....... Where did you learn how to read? He stated he had the repairs done in 'reply' to my post, not in the original post. Mike > > If someone told me I had air in the brakes I would wonder just 'how' did > > that air get there? It can't be created, it has to have been introduced [quoted text clipped - 55 lines] > http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups > ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- > Where did you learn how to read? > > He stated he had the repairs done in 'reply' to my post, not in the > original post. I thank you as well Mike for trying to help. Uhuh, one can deduct from my posts that two mechs already found nothing wrong with the system short of the first one who DID replace the Brake Pads (something I omitted from my post, sorry. But I did so merely because all I needed from here was the answer to my original question). BTW, I respect the inputs of folks like you on the Net BECAUSE you've nothing to lose and aren't looking to get a buck out of me. Thx! As for this character Jim, I've seen from some of his other posts on Usenet that he's the occasional loser with the knack for insulting others on a whim. > Where did you learn how to read? > > He stated he had the repairs done in 'reply' to my post, not in the > original post. Well that was my point he didn't reveal that so you are off trying to figure out how air got in the lines. He won't say what the shop did or what their opinion of what the current condition of the brakes is. -jim change the master cylinder if you want to fix your problem ,if you do not you will contenualy having sponges brakes as it been mentioned be for.... Signaturealan &marge pepper http://www.automotiveforums.com >change the master cylinder if you want to fix your problem ,if you do >not you will contenualy having sponges brakes as it been mentioned be >for.... and change the booster if that doesn't fix it and replace the slave cylinders if you're still getting air in the system after that, change the brake lines. Or better yet, see where the air is getting in and just fix that. >>change the master cylinder if you want to fix your problem ,if you do >>not you will contenualy having sponges brakes as it been mentioned be [quoted text clipped - 5 lines] > >Or better yet, see where the air is getting in and just fix that. Or fixing the binding caliper slide pins or fix the misadjusted or misassembled rear brakes? Don www.donsautomotive.com Cyber Wrote: > Hello. I've been up and down different info resources online and even to > a [quoted text clipped - 14 lines] > > I'd truly appreciate any input regarding this. Thanks in advance. The best way to tell is to do a proper bleeding procedure on the system. Some ABS brake systems require a scan tool to bleed. Also you may need a pressure bleeder. One of the first test is with engine off pump the brakes to remove vacuum from brake booster and see how the brake feel. You should then have a full firm pedal. Do you? Tips on getting a good answer to your questions. People trying to answer your question do not have a crystal ball. So give them all of the info you have like year make and model and engine and transmission and mileage. Also cars engine and transmission service history or any recent repairs or problems. Also a description of your problem and what it is doing or not doing. If you have codes give up the code no. And remember a code does not say replace the part but only points to the problem that you have to check out. So to better help you give up all of the info you have on it. MT Tips on finding a good mechanic/repair shop. Check around Ask around Word of mouth. Family friends coworkers neighbors business people and delivery people. Mailmen and parcel delivery people get around and notice a lot of stuff. Even a good parts house knows what shops are good and not good. Chamber of commerce and better business bureau and city hall. If you find a good referral to a repair shop go look them over and talk to them. Look for a clean looking busy place with nice people running it. Ask a few questions and ask about their qualifications and training. Not all places have trained tech/mechanics. If they do not find a place that does. Even all dealers do not have all trained techs/mechanics. SignatureMT-2500 http://www.automotiveforums.com > How else apart from actually driving the car can the Mech come to the > conclusion that the brake line has to be bled? (eg, there's air in there?). So why hasn't the mechanic driven the car? Maybe you can't tell by other means. Maybe it's just the simplest and most direct way to tell. So have them drive the bloody thing and know for sure. |
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