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Car Forum / Driving, Maintenance, Tuning / Maintenance and Repair / July 20071994 Ford Escape - low brake pedal height
hello all ... 1994 Ford Escape V6, front discs, rear drums, right at 35,000 miles. replaced the front rotors and pads. the brake pedal moves closer to the floorboard than is usual. the brakes do stop the vehicle, but the pedal is much closer to the floor now (than is usual). (i did not replace the rear shoes/drums as they still have some life left). initially, i was going to have the rotors turned, so i compressed both front calipers to remove them so i could take both rotors off. turns out the rotors were already at their minimum thickness, so i bought 2 rotors, installed them, the new pads, bolted up the calipers, topped off the brake fluid, then took the truck out for a test spin. initially, when i pushed on the pedal, it would get to a firm state, then the pedal would move down a bit more, so i deduced that i should bleed the brakes. so with the aid of a helper, we did the typical "pump the brakes, hold it, open the bleeder screw, close it, pump, etc". it took about 3 cycles of this procedure [for each wheel] to clear the fluid of any trapped air. after the bleeding procedure, i took it out for another test drive and we are at the point where "the pedal goes further to the floor than is usual". any thoughts about this? is it maybe a bad master cylinder? or maybe another brake-bleeding session is required? also, i noticed the brake fluid in the system is black. maybe a brake system flush? thanks! >also, i noticed the brake fluid in the system is black. maybe a brake >system flush? > >thanks! A flush sure won't hurt and would get any other trapped air that is in the system out. Also if you have drums in the back go ahead and pull the drums and manually adjust the rear shoes. Steve B. > On Mon, 02 Jul 2007 11:34:00 -0000, LinuxTester <myswt...@hotmail.com> [snipped] > A flush sure won't hurt and would get any other trapped air that is in > the system out. Also if you have drums in the back go ahead and pull > the drums and manually adjust the rear shoes. hi Steve ... thanks! i did nothing to the rear drums brakes, except to remove the drums to check the shoes, so i will adjust the rear drums this afternoon. > hello all ... > > 1994 Ford Escape V6, front discs, rear drums, right at 35,000 miles. The best I can tell from all of the clues is that you most likely have a 2004 Escape, or less likely, a low mileage 1994 Explorer. Now, does your (fill in the blank) have ABS? Toyota MDT in MO > > 1994 Ford Escape V6, front discs, rear drums, right at 35,000 miles. > > The best I can tell from all of the clues is that you most likely have > a 2004 Escape, or less likely, a low mileage 1994 Explorer. good catch Comboverfish ! ... can't believe i typed "1994" ... the title should read: "2004 Ford Escape - low brake pedal height" ... and in the body of the text, it should read: "2004 Ford Escape V6, front discs, rear drums, right at 35,000 miles." > Now, does your (fill in the blank) have ABS? i dont have a definitive answer until i get to the vehicle later this afternoon and double-check. there is no wiring going to the calipers (only hydraulic brake lines), but i do remember seeing what could be an ABS electro-magnetic ring on the front drive shafts. (not my Escape). thanks! michael > > > 1994 Ford Escape V6, front discs, rear drums, right at 35,000 miles. > [quoted text clipped - 16 lines] > > thanks! michael If you have ABS, then there is a possibility of suspended contamination at the lowest points of the system (front calipers) being forced back through the normally open ports of the ABS hydraulic modulator and even into the master cylinder during piston retraction. This can block small passages, possibly keeping your master cylinder pistons from properly replenishing with fluid. This scenario is not likely but should be mentioned. In the future, squeeze brake fluid out of the bleeders into a waste container when retracting caliper pistons to be on the safe side. If this just happened after pad replacement and it is not due to air trapped in the system, I would be double checking your brake pad installation. Make sure that the rotors are seated squarely and fully on the hubs as well. Check for any binding parts that should slide freely as well as pads or shims that aren't squarely in their mounts. Toyota MDT in MO > If you have ABS, then there is a possibility of suspended > contamination at the lowest points of the system (front calipers) [quoted text clipped - 5 lines] > out of the bleeders into a waste container when retracting caliper > pistons to be on the safe side. yep - this Escape has ABS ... > If this just happened after pad replacement and it is not due to air > trapped in the system, I would be double checking your brake pad > installation. Make sure that the rotors are seated squarely and fully > on the hubs as well. Check for any binding parts that should slide > freely as well as pads or shims that aren't squarely in their mounts. i've checked the rotors and they are seated squarely and fully on the hubs (i had wire-brushed the hubs to clear them of rust/etc before putting on the new rotors). the pads are seated squarely to the rotors and all turn freely as they should. my next steps are to adjust the rear drums/shoes and then vacuum bleed the system (i have a MityVac). any other suggestions are welcome. regards, michael no joy on second attempt ... (2004 Escape, ABS, front disc, rear drums, 35,000 miles) summary (initial procedures): * replaced front rotors * replaced front pads. * removed drums to inspect shoes - shoes okay, so re-installed drums (did not adjust drums at this time) * low brake pedal, so did a two-person bleed routine at all four wheels (Note: did not open bleed valve when compressing front caliper pistons, but allowed fluid to "bleed" back to master cylinder) still had a low pedal after above procedures, so last night: * adjusted the rear drums (per Steve B) * vacuum bleed (using MityVac) at all four brakes. same issue - low brake pedal. if i pump the pedal, it does come up. any suggestions? maybe a new master cylinder is in order? > no joy on second attempt ... > (2004 Escape, ABS, front disc, rear drums, 35,000 miles) [quoted text clipped - 18 lines] > > any suggestions? maybe a new master cylinder is in order? It still sounds like you have air in the system, or some manner of replenishing/compensation port issue in the master cylinder. I have not worked on Escape brakes to have a visual of how the system is laid out, so I have no specific pointers or silver bullets on this issue. If the original work you did truly caused the problem (before you opened the hydraulic system, i.e. JUST the pad and rotor replacement) then I would still be worried that some crap has made it into the HCU or master cylinder. Perhaps it's time for someone with a Ford scantool (IDS, PDS, NGS, or WDS) to active test the ABS solenoids and try an active bleed procedure before hanging any parts. RE: Escape ABS active tests: I don't know if those options are available on the Ford testers or for that matter if a common Snap On Scanner would do it. With the low volume of Ford work I see at home, I treat each one as a new experience :) If this is a perceived low pedal issue (I'm not saying it is, but for sake of argument) it could be due to a certain quality or composition of brake pad, a coating on the rotor, or combination of the two that is requiring *more pedal stroke* for the same amount of braking action as before the repair. I know you said that the pedal gets higher with quick repeated strokes, but even a perfect brake system will do that to a minor extent -- vacuum gets depleted from the booster, fluid gets trapped behind the master's pistons before the caliper pistons have a chance to relax, etc. Try pumping the pedal rapidly on a known good car (w/ vacuum booster) next time you get the chance. The pedal will get harder and higher, but it is normal. Again, I'm sure this is not the case with you as you seem to know your vehicle very well; just thought I'd throw it out there. Toyota MDT in MO P.S. I would suggest two-man bleeding any problem vehicle such as this one. Do not trust the Mityvac to evacuate trapped air. You will also draw "false" air from the bleeder threads, which can throw off your visual inspection of air in the tubing. Oh, and kudos on the wire-brushing of the hubs before rotor installation. first off, thanks for your very detailed and insightful responses, Comboverfish! > > maybe a new master cylinder is in order? i threw the above idea out because last year, i replaced rotors/pads/ calipers on a Trooper and experienced something similar. it was suggested that the master cyl was clogged up, so i replaced it and the issue went away. (low pedal). > It still sounds like you have air in the system, or some manner of > replenishing/compensation port issue in the master cylinder. I have > not worked on Escape brakes to have a visual of how the system is laid > out, so I have no specific pointers or silver bullets on this issue. i'll do the two-man bleed again and see how it goes. i searched for a manual for more specifics, but both Haynes and Chilton only go up to year 2003 (titled, "Ford Escape and Mazda Tribute, 2001-03"!) > If the original work you did truly caused the problem (before you > opened the hydraulic system, i.e. JUST the pad and rotor replacement) > then I would still be worried that some crap has made it into the HCU > or master cylinder. Perhaps it's time for someone with a Ford > scantool (IDS, PDS, NGS, or WDS) to active test the ABS solenoids and > try an active bleed procedure before hanging any parts. [snip] if this last bleed doesnt work, then i'll drive her up to the local repair shop and see what they can offer. > If this is a perceived low pedal issue (I'm not saying it is, but for > sake of argument) it could be due to a certain quality or composition > of brake pad, a coating on the rotor, or combination of the two that > is requiring *more pedal stroke* for the same amount of braking action > as before the repair. interesting - i would not have considered this. the pads are semi-metallic's with "BrakeBest" rotors (made in China as most all are ... purchased from Oreilly Auto Parts). i wiped the rotors down with acetone as the rotors had a (sealed in plastic) yellowish film on them (probably anti-rust). > I know you said that the pedal gets higher with > quick repeated strokes, but even a perfect brake system will do that > to a minor extent -- v yep - you're right. i'm going by my friend's assertion that the pedal feels low. > P.S. I would suggest two-man bleeding any problem vehicle such as will give this a go later on this afternoon. > this one. Do not trust the Mityvac to evacuate trapped air. You will > also draw "false" air from the bleeder threads, yep - even the MityVac manual has, "you may see very tiny bubbles coming through the hose - this will [most likely] be air coming around the threads". they suggest putting teflon tape on the threads to stop this. > Oh, and kudos on the wire-brushing of the hubs before rotor installation. i picked that up from reading some posts out here - maybe it was a reply-post from you :) BTW, how can i be sure that the brakes ARE fine and the low pedal is just a figment of my friend's imagination? is there a "brake pedal" measurement that says something like, "if the pedal moves more than xxx inches, than there is a low-pedal problem". ?? > BTW, how can i be sure that the brakes ARE fine and the low pedal is > just a figment of my friend's imagination? is there a "brake pedal" > measurement that says something like, "if the pedal moves more than > xxx inches, than there is a low-pedal problem". ?? I have never run across such an etched in stone specification, or have simply forgotten such. There are related failure specs given by my state's DOT safety inspection program, but they surpass that which is sensible and obvious. I really don't remember the travel limitations as specified by our DOT; they are well past the point where I would already have indicated brake failure to the vehicle owner. I'd say that most pedals easily sink over one inch with light foot pressure (just enough to keep the car from moving while in gear). As a rule of thumb, domestic brakes seem firmer to me than Asian given the same operator pressure. That phenomenon is probably changing more every year as parts sourcing and technology swapping increases exponentially. Any time that you have to increase pedal stroke to maintain the same stopping power then there is a problem. Example: stopped at a light you press the pedal down 1.2" with x force. 10 seconds later the car starts to creep, so you apply x+1 force which requires 1.5" of pedal stroke. That's a problem with internal leakage, usually in the master cylinder. Note: any load changes such as A/C compressor cycling will change brake feel If the brake system uses an all-in-one hydraulic master/ABS unit, diagnostics can get hairy and expensive. With a separate master like on your system diagnosis should be easy. IOW, the pedal should not drop with steady pressure on it. The best, quickest test for a bypassing master cylinder *is* to apply steady light pressure and see if the pedal sinks. The best test for air in the system is to see if the pedal pumps up significantly. Both of these tests should be carried out either with the engine running, or after depleting the booster vacuum reserve if the engine is off. Try the tests both ways. I just checked my Snap On scanner with current software, and it shows an automatic ABS bleed procedure available. Most shops worth anything will have either a recently updated Snap On or some form of OEM Ford scan tool. The scanner approach still is the best way to go IMO. My info shows to perform this auto bleed several times, then follow up with several two-man manual bleeding passes around the vehicle, right rear, left rear, right front, left front. As an additional caution, I would slow bleed the master at both fittings first before doing anything, just to be safe. Toyota MDT in MO |
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