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Car Forum / Driving, Maintenance, Tuning / Maintenance and Repair / March 2006drum brake lockup issue...
Below is a copy of a post to alt.autos.studebaker... if you can shed any light on my problem please make whatever suggestions you think might help. Just for background, this is a '55 Studebaker Commander 5-passenger coupe (the "sports coupe" or "Loewy coupe" body style.) Nearly rust-free Texas car. Stock 4-wheel drum brakes with stock under-floor single reservoir master cylinder. "anti-creep" is basically an electrical line lock that was installed on cars with Detroit Gear automatic transmissions that activated only when the engine was at idle (kept the car from creeping forward at stop lights, hence the name.) Since my car lost its stock transmission long before I got it, the wires to the anti-creep have been cut but since the brake lines have never been replaced (as it's a nearly rust free Texas car) the valve is still physically there. This is driving me nuts as there's a big all-Stude swap meet this coming weekend about 2 hours' drive from me :( I don't know what the heck is wrong; Studebaker brakes, even the drums, in my experience are excellent and easy to work on. This is the first car that has given me serious issues (and coincidentally the nicest Studebaker I've ever owned, and the one I'd like most to drive.) nate -- OK guys (and girls too) I am out of ideas as to what to do with my '55 coupe. There's two main problems that keep it from being a nice driver; the first being that the steering box is shot and the second is that my rear brakes lock up under somewhat hard (but nowhere near panic stop) braking. The first I know how to deal with, if I can ever find another steering box. The second I am clueless as to how to fix. Since buying the car, I have replaced all shoes, all wheel cylinders (I may have rebuilt one of the rears with a kit; not sure. I know I replaced at least one, maybe both. Both fronts are new.) cleaned everything, replaced all hoses, replaced master cylinder. I have had all drums off since noticing this problem and nothing really seems amiss. All shoes were from Fairborn Studebaker, so I assume they have the same lining material. I thought initially that this problem might be because the rear tires that came with the wheels I bought from JP might be old and hard. Well I swapped the wheels front to rear and discovered that a) you CAN fit 245/60s on the front of a C-K body if you really want to, and they look cool in an insane, over-the-top kind of way. Steering is kinda hard though. Cop car wheels with a 1/4" spacer. Just so you know. b) Yokohama AVS ES100 tires smell a hell of a lot worse than BFG T/As when you smoke 'em. Yup, the lockup remains at the rear. There are only a couple things that I noticed when looking at the brakes AGAIN today... 1) the pass. side front drum is fairly tight - I have the adjuster backed all the way off and it drags just a little more than I'd really prefer. Didn't want to have the drum cut, however. 2) I suspect that the pass. side front drum is newer than the driver's side, as it is a tighter fit on the shoes, and also the driver's side has some vague rust spots on the braking surface that the pass. side does not have. Does not feel overly worn though, although I don't have brake drum calipers. 3) The pass. side front when I pulled the drum off was squeaky clean. The driver's side, however, had lots of brake dust inside. When I pulled the rears last, I don't remember either having an unusual amount of dust, neither more nor less than I expected. 4) The anti-creep solenoid is still installed on my car, although the wiring is long gone. I am thinking that my next step will be to bypass this valve and see what happens, but I can't imagine that it could do anything to make the rears lock first. Any ideas as to what to do next would be greatly appreciated. I didn't replace any of the springs etc. as they all looked to be in good condition (possibly replaced when previous brake job was done.) I don't feel like I cut any corners on this brake job and I find it odd that this one is fighting me; usually I just disassemble, fix/replace what I see that needs fixing or replacing, and voila, the car stops like it should. I *really* wish I had a couple little tees with some brake pressure gauges so I could see if I had a hydraulic problem or a mechanical problem. But I don't. Such is life. thanks... nate PS - after driving the car around the last couple days, if it weren't for this little issue, I might just consider driving it to York, esp. after I got my backup lights and driver's door mirror installed. BTW the repro mirrors have JUST BARELY enough adjustment to be useful, at least for me... I don't know if I get one for the pass side if I will be able to use it without undercutting the pivot ball some. But anyway it kind of pisses me off that I seem to have a fully functional car and I still can't (safely) drive it...  Signaturereplace "fly" with "com" to reply. http://home.comcast.net/~njnagel "Nate Nagel" wrote: '55 Studebaker Commander Rear brakes lock up under somewhat hard braking. Stock 4-wheel drum brakes Stock under-floor single reservoir master cylinder. Has "anti-creep" electrical line lock which activates only when the engine idles to kept the car from creeping forward. Wires to the anti-creep have been cut but brake lines have never been replaced; the valve is still there. I have replaced all shoes, all wheel cylinders, cleaned everything, replaced all hoses and master cylinder. Pass side front drum: The adjuster is backed all the way off and it drags just a little more than I prefer. _____________________________________________ BRAKE SHOE DRAG: Shoes should not drag at all. When released, the pivot end of the shoes should stay near but not touching the drum, while the brake springs pull the moving shoe ends inward and squeeze the fluid out of the wheel cylinder, back into the master cylinder and reservoir. A relief valve stops the shoes from further retracting when the proper residual line pressure is reached. If a shoe drags it may be caused by: a.) Parking brake left on. b.) Wrong shoe - curve does not match drum. c.) Weak shoe return springs. d.) Jammed cylinder piston. e.) Master cylinder pushrod not fully released. f.) Leading/trailing shoes interchanged. g.) Front and Rear shoes interchanged. h.) Creep-valve not bypassed. i.) New shoes not broken in (10 hard stops). j.) Adjuster too tight. l.) Defective master cyl relief valve. m.) Front/rear Master cyl lines interchanged. n.) About 50 other things I can't remember. BRAKE SHOE LOCKUP: Take a drum off, have someone push on the brake a little (not far enough to blow the pistons out of the wheel cylinder). Observe whether the springs quickly and smoothly retract the shoes. The shoes should stop after retracting, but should not retract all the way to the stop post. If it retracts all the way, the residual line pressure relief valve is defective There may be nothing wrong: Rear tires can skid during hard braking because the larger front brakes do most of the work and the load on the rear axle gets lighter when stopping. The rear brakes may temporarily grab, but release when pressure is released. Brake grabbing may also result from oil on the shoes. If it is the wrong shoe, the pivot end may be too far from the drum, causing the self-energizing feature of drum shoes to jam the shoe into the drum. Front brake shoes or pistons should be larger than those of rear brake shoes to lessen rear tire skidding. If not, there may be proportional valving in or near the master cylinder to reduce the pressure applied to the rear shoes. Good luck. Rodan. I would look at the brake shoes again to determine that all four shoes are identical. If you notice that two are thicker and have a different friction material length from the other two then you have "self-energizing" brakes. The thicker shoe is called a "lead" shoe. It of course is the front shoe whilst the shorter, thinner shoe is the trailing. Shoes that are too thick will not allow the shoes to "energize", or pivot on their posts mechanically "wedge" against the drum. You say you have one that is dragging even with the adjuster fully retracted, and this should be looked at closely. Re-check for leading shoes, re-bleed, re-adjust. If you replaced the master cylinder you might want to look at the actuator rod length; if it is too long the master cylinder may not be able to function correctly. That is if it is indeed the correct master cylinder. DieInterim SignatureDieInterim http://www.automotiveforums.com Nate, Who made the steering box? Ross, Saginaw? What is actually wrong with it? On the brakes, does the lockup happen every time? From your description it sounds like the front brakes are not working fully. Maybe you should pull apart the clean passenger side cylinder and make sure it is working. Possibly the shoes are just a bit thick and they are making the pistons bottom out and blocking the brake fluid port. If one side isn't working that could be enough to cause your problem, since 80% of the braking is done in the front end. Measure the lining on the shoes, Are they shoes that can be used in all positions or are they leading/trailing like the newer ones. SignatureSteve > Below is a copy of a post to alt.autos.studebaker... if you can shed > any light on my problem please make whatever suggestions you think might [quoted text clipped - 93 lines] > it kind of pisses me off that I seem to have a fully functional car and > I still can't (safely) drive it... > Nate, > Who made the steering box? Ross, Saginaw? What is actually wrong with > it? It is a Saginaw box with integral power; it's basically just very, very sloppy. I have cone through the front end and at least looked at everything except the center pivot and tie rods, and those don't appear to have any appreciable play in them. The box also won't hold gear oil; it's packed full of chassis grease for the time being (it's better than nothing at all) > On the brakes, does the lockup happen every time? > From your description it sounds like the front brakes are not working [quoted text clipped - 5 lines] > lining on the shoes, Are they shoes that can be used in all positions or > are they leading/trailing like the newer ones. yes, it pretty much happens every time. I only notice the lockup when I brake a little harder than I normally would, but not much harder. I would guess 0.3G or thereabouts. That's a good thought about the pistons bottoming, but I don't think that's the problem as the shoes moved when I tried the brakes with the drum off... I am pretty sure that there's distinct primary/secondary shoes and that I got them in the right positions, but I will have to check again of course... nate > Below is a copy of a post to alt.autos.studebaker... if you can shed > any light on my problem please make whatever suggestions you think might [quoted text clipped - 53 lines] > backed all the way off and it drags just a little more than I'd really > prefer. Didn't want to have the drum cut, however. Can you find a brake shop--possibly an older, established one--that has a machine to "true-arc" the shoes? In older days, we had drums mic'd and the machine set up to match, and true the shoes so as to fit 'perfectly' the circumference of the drums. Sure made for an all-around fit between shoes/drums. The slightest high spot will cause a pumping and friction action that heats and swells the shoes, leading to.....you guessed it, a lockup! HTH, s >>Below is a copy of a post to alt.autos.studebaker... if you can shed >>any light on my problem please make whatever suggestions you think might [quoted text clipped - 61 lines] > action that heats and swells the shoes, leading to.....you guessed it, a > lockup! HTH, s I wish... I actually thought about that, since none of the shoes have perfectly worn to the drums yet. But no, I don't - if anyone knows of one, preferably not too far a drive from Annapolis, MD - I'd be all ears. nate Signaturereplace "fly" with "com" to reply. http://home.comcast.net/~njnagel Nate barring finding anything as suggested here, which covered all the bases I would, you could install an adjustable proportioning valve and custom bias the brake hydraulics. >>>Below is a copy of a post to alt.autos.studebaker... if you can shed >>>any light on my problem please make whatever suggestions you think might [quoted text clipped - 67 lines] > > nate . . <<inline>> ======= ======= > Below is a copy of a post to alt.autos.studebaker... if you can shed > any light on my problem please make whatever suggestions you think might [quoted text clipped - 97 lines] > replace "fly" with "com" to reply. > http://home.comcast.net/~njnagel ======= ======= Nate, if "any" of the drums are not sliding on and off the vehical easily, remedy that situation first. You need clearance to keep the brakes from dragging, which "will"...heat the brakes, which will in turn heat the brake fluid, which in turn will expand, which in turn will apply the brakes whether yer foots on the pedal or not. Fact.....not Fiction. next..... jack that sucker up in the rear and run it up to 50mph or so a couple times and see if you can get the brakes to lock up in the rear. It may take a bit of doing...but if it'll do it on the road it should do it on the rack. Not recomended procedure for a DIY'r....but try holding the pedal down a bit to creat jest a little drag while you're running the speed up to 50mph. Don't over do it...yer jest try'n to create a load to simulate stopping that beast on the road. any whooo.... if you can get the brakes to start binding in the rear.... CUT A BLEEDER LOOSE.....and see if the wheel spins then. You may have some restriction in the lines....which was my first thought after reading you're post. remember....fix the clearance deal first. submitted for consideration, rebute, debate, or flames ~:~ MarshMonster ~:~ > Below is a copy of a post to alt.autos.studebaker... if you can shed > any light on my problem please make whatever suggestions you think might [quoted text clipped - 20 lines] > > nate Followup... today I took the rear brakes apart again to replace the rear wheel cylinders that I bought on Monday. I figured while I had it apart I would clean and paint the backing plates (didn't do that before, in my hurry to get the car on the road.) Here's where I found something interesting; on BOTH backing plates, all of the little "pads" that the shoes ride on were in excellent shape, EXCEPT two of three for the primary shoe - the top one by the anchor pin and the bottom one by the star wheel were deeply grooved. Again, this was on both sides, and the wear patterns were similar. I wonder if maybe someone had the drums cut and whoever did it left a little "spiral" on the wearing surface and the shoes were chattering? who knows... Now I wouldn't have noticed this if I hadn't taken the backing plates off the car, as those pads are difficult to look at when you're bending down to look under the quarter panel. The middle one by the hold down (the one that your eye is naturally drawn to) was fine. I don't have any explanation for this, but I went ahead and laid a bead of MIG weld down on there and ground it back smooth. I am fairly certain that this issue does not exist on the fronts as I cleaned and painted the front backing plates when I rebuilt the suspension. The paint on the rear backing plates is drying now so I will reassemble tomorrow and see if it did anything. Will bypass the anti-creep valve before bleeding. I've put a few more careful miles on the car, and since I cleaned everything real well last weekend I can see exactly where the shoes are contacting the drums. The secondary shoes are making maybe 50% contact, but the primaries a lot less, almost as if the grooves really were holding the shoes up. Also it may be my imagination but even after putting maybe only 50 more (careful!) miles on the car since the last time I posted the rears feel less "grabby" - I haven't had the brakes lock up in traffic at all, although when I really tested them in front of my friend's house the rears still locked before I thought they should. So I am wondering if really the fact that the rear shoes aren't completely worn in is the main problem. Well, anyway, we will see if this helps... I haven't pulled the driver's side front yet since my original post; I am curious whether or not it is still getting more dust than the pass. side. However, in retrospect, I think most of the dust that I saw may have been rust wearing off the drum - IIRC that wheel had a completely seized wheel cylinder when I got the car and that drum had more surface rust on it than the others. If I have time tomorrow I will probably pull it again just to make sure nothing is amiss. nate (I just want to drive my car! Is that too much to ask?) Signaturereplace "fly" with "com" to reply. http://home.comcast.net/~njnagel > = > Followup... > = > today I took the rear brakes apart again to replace the rear wheel > cylinders that I bought on Monday. I figured while I had it apart I [quoted text clipped - 4 lines] > primary shoe - the top one by the anchor pin and the bottom one by the > star wheel were deeply grooved. Again, this was on both sides, and the= > wear patterns were similar. I wonder if maybe someone had the drums cu= t > and whoever did it left a little "spiral" on the wearing surface and th= e > shoes were chattering? = The top and bottom tend to get the grooves because the movement of the shoe tends to follow the direction of the edge of the shoe. At the middle it's is moving at 90=B0 to the edge. The problem tends to develop when you stick on new shoes and the groove is in the wrong place (the edge of the shoe is riding on the edge of the groove instead of the middle). You will probably notice the shoes have a little wrinkle in the edge where they contact the backing plate. If designed right that goes along way to spread the load and keep the edge from knifing into the backing plate. But some designs tend to cut in worse then others. Old Ramblers come to mind. >who knows... Now I wouldn't have noticed this > if I hadn't taken the backing plates off the car, as those pads are > difficult to look at when you're bending down to look under the quarter= > panel. The middle one by the hold down (the one that your eye is > naturally drawn to) was fine. I don't have any explanation for this, > but I went ahead and laid a bead of MIG weld down on there and ground i= t > back smooth. I am fairly certain that this issue does not exist on the= > fronts as I cleaned and painted the front backing plates when I rebuilt= > the suspension. > = > The paint on the rear backing plates is drying now so I will reassemble= > tomorrow and see if it did anything. Will bypass the anti-creep valve > before bleeding. > = > I've put a few more careful miles on the car, and since I cleaned > everything real well last weekend I can see exactly where the shoes are= > contacting the drums. The secondary shoes are making maybe 50% contact= , > but the primaries a lot less, almost as if the grooves really were > holding the shoes up. = Which 50% is making contact? Is it in the middle? one end? or both ends? That doesn't sound good, it shouldn't take much wear to get 100% contact if they are at all close to the right size to begin with. -jim > Also it may be my imagination but even after > putting maybe only 50 more (careful!) miles on the car since the last > time I posted the rears feel less "grabby" - I haven't had the brakes > lock up in traffic at all, although when I really tested them in front > of my friend's house the rears still locked before I thought they > should. So I am wondering if really the fact that the rear shoes aren'= t > completely worn in is the main problem. Well, anyway, we will see if > this helps... > = > I haven't pulled the driver's side front yet since my original post; I > am curious whether or not it is still getting more dust than the pass. > side. However, in retrospect, I think most of the dust that I saw may > have been rust wearing off the drum - IIRC that wheel had a completely > seized wheel cylinder when I got the car and that drum had more surface= > rust on it than the others. If I have time tomorrow I will probably > pull it again just to make sure nothing is amiss. > = > nate > = > (I just want to drive my car! Is that too much to ask?) > = > -- > replace "fly" with "com" to reply. > http://home.comcast.net/~njnagel > > Followup... > > [quoted text clipped - 44 lines] > That doesn't sound good, it shouldn't take much wear to get 100% contact > if they are at all close to the right size to begin with. Seems to be both ends, although the middle part of the shoe is showing signs that it's starting to make contact with the drum as well. nate > Seems to be both ends, although the middle part of the shoe is showing > signs that it's starting to make contact with the drum as well. Ah, so if we can assume the shoes themselves are right ones for this car then probably the remanufactured linings are a lot thicker than the original manufacturers lining. So that isn't altogether bad since eventually they will wear to the right size. -jim > > > Followup... > > > [quoted text clipped - 49 lines] > > nate That 'really' implies the shoes are the wrong size. The arc is wrong. Might only be too big by a little but.... If you can get them to finally break in, then you will have to watch them close as they wear. The ends will go metal on metal long before the center is worn out.... There are shops local to me that will take the old metal shoe frames and put new friction material on them. I think I would be looking at that rather than trying to drive with shoes that don't grab evenly.... 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) >>>>Followup... >>>> [quoted text clipped - 54 lines] > finally break in, then you will have to watch them close as they wear. > The ends will go metal on metal long before the center is worn out.... not "long" but probably... they'll never get to that point, though, I do try to take care of my vehicles :) I think it's probably only out by a few thousandths. > There are shops local to me that will take the old metal shoe frames and > put new friction material on them. I think I would be looking at that > rather than trying to drive with shoes that don't grab evenly.... I already turned in my cores, I don't think there's anything wrong with these, the problem is that they probably do need to be "arced" but I don't have an old school brake and clutch shop anywhere around, or if I do, I don't know about it. :/ I put everything back together today and I really don't know how I could have done anything better. Everything is spanking clean, unless it's supposed to be lubed in which case it has fresh white lithium on it. New wheel cylinders, hoses, and MC, new linings from the same source all around, only difference is that the fronts have maybe 1-200 more miles on them than the rears. I did NOT get a chance to bypass the anti-creep today as I had to take the time to drill out a busted parking brake cable retainer bolt (fun fun fun) and needed to get the car back together and out of my friend's garage. The rear brakes are still locking up prematurely, but I swear that the more I drive it the better it seems to brake. I think I am going to remove the anti-creep valve next weekend anyway just to eliminate all possibilities, but tell me if this sounds like a dumb idea - set the car up on jackstands in the driveway (or on a lift if it is warm enough to keep the garage door open,) run it up to about 50 MPH wheel speed, brake to zero under light power, lather, rinse, repeat until the rear shoes are worn in. THEN go for another test drive and see if it is still being a pain in the arse. If *that* doesn't work, I will take apart the fronts AGAIN and do the same careful inspection of all components and see if anything pops out at me (like the grooves in the backing plate that I'd missed before) and then if I don't find anything I will have to admit defeat and simply install a prop valve. BTW to the other poster who mentioned the springs; I thought of that but they all appear to have been replaced at the last brake job as they all still have paint on them. If wearing in the shoes doesn't fix the problem I do have Wagner part numbers for the springs, I will see if my FLAPS can hook me up. nate PS - on the upside, I think I am close to resolution of another problem with this car that's keeping it from being a nice driver; I picked up a "condition unkown" steering box at a swap meet a couple weeks ago and started cleaning it up today. Not only is it nice and tight, but I filled the gearbox up with gasoline and it seems to be holding (which is better than the one in the car, which gear oil runs right through and chassis grease kind of oozes out of after a while) Signaturereplace "fly" with "com" to reply. http://home.comcast.net/~njnagel Nate, IIRC, you were looking for the edge code for the brake shoes. You can see this at the URL here http://www.findarticles.com/p/articles/mi_qa3828/is_199909/ai_n8870799 The code consist of two letters from the group near the bottom of the first page. The first letter is the normal static friction. The second is with the shoe hot in a fade test conducted under an SAE standard which I won't get into for your purposes. If you look closely at the codes and the friction range, you will see that the effective friction can vary by as much as 40% with the same code. This means you could have grossly different braking effectiveness between two wheels of the with brakes of the same rating ie you installed front brakes this weekend with Brand "X" pads or shoes and a few weeks later use brand "Y" on the other end of the vehicle. Even though they have the same code, they may be grossly different in operation. This is true of pads or shoes and is why it is recommended that they always be replaced in at least pairs on the same axle. This difference can also result in a big difference from front to rear. I recently replaced the front pads on my F150 which had Wagner FF pads with Bendix FF pads. The Bendix pads are much more aggressive. This is noticeable when towing a heavy trailer making the front wheels easy to lock. Another problem you may run into on older cars is weak return springs on the shoes. This is almost an afterthought with many who replace brakes but, the higher the friction factor of the shoes as indicated above, the greater the self energizing effect of shoes when applied. This can only be controlled with good return springs. Lastly, make sure you have a good return on your brake pedal if you have a vacuum booster. If it is not completely releasing the brakes, some or all of the shoes may be running warm because of slight dragging causing them to be more aggressive than they should be when applied. The brakes are designed to run at some "normal" temperature allowing for them to heat during application. As you brake, you subconciously compensate for the increase in braking efficiency such that you never really notice it. Hope this enlightens a little and you resolve your problem. Lugnut >> Below is a copy of a post to alt.autos.studebaker... if you can shed >> any light on my problem please make whatever suggestions you think might [quoted text clipped - 71 lines] > >(I just want to drive my car! Is that too much to ask?) |
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