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Thread: Excessive brake pedal travel

  1. #1
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    Excessive brake pedal travel

    I've been experiencing this for quite some time now, and I need to get it sorted. So I'd really appreciate some suggestions on what I need to do/replace. Car is a '01 E39 530i.

    The actual braking power does not seem to be an issue, it's mainly excessive travel accompanied by a slight sponginess. However when I hold the pedal down (at traffic lights for instance), it doesn't budge - I believe if a faulty master cylinder was present the pressure would drop and the pedal would drop to the floor, but it doesn't.

    The brakes have been bled recently with fresh fluid (using DIS/GT1 to vent ABS valves also) as was the clutch slave. Front calipers are new and I'm running stainless steel lines all round.

    I even had a friend comment recently saying my "brakes aren't great" as they had to use more force/travel to get them to engage.

    Could the brake servo (booster) be the issue? Or could it still be the master cylinder even though it seems to be holding pressure?

    Thanks in advance.


  2. #2
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    My first suspicion would be air in the brake system. If a pressure flush of the system fails to cure the problem, there could be air in the ABS unit, which requires the servies of a GT1 or similar to cure.
    The car makes it possible, but the driver makes it happen.
    Jim Levie, Huntsville, AL

  3. #3
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    Thanks for the reply.

    That's the thing though, I have a GT1 and followed the brake bleeding procedure outlined, which included venting of the valves in the ABS unit, so I'm very confident there is no trapped air in the system. It's a bit of an awkward one really, as I'm struggling to find out what I need to replace to cure the issue.


  4. #4
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    Are the new front calipers OEM or aftermarket? If they're not OEM, they may hold the pads slightly farther away from the rotors, and that distance has to be taken up by pressing the brake pedal farther.
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  5. #5
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    Quote Originally Posted by Critter7r
    Are the new front calipers OEM or aftermarket? If they're not OEM, they may hold the pads slightly farther away from the rotors, and that distance has to be taken up by pressing the brake pedal farther.
    Not necessarily. Because if your theory is correct then anytime a brake pad starts to wear your brake pedal would need to travel farther And farther. The problem now seems to be the a sponginess feel. This wouldn't make A difference but what new brakes Re you running?

    When I changed my front brakes to stoptech bbk with stainless steel lines, I also used a pressure bleeder and thought I got everything out. The brakes where still spongy and took the longest time to figure out why that is. After much searching I decided to pump he brAkes while the car was off, open one of the bleeder valve and again press on the brakes hard. After that a couple small bubbles came out and the brakes are working perfectly again.

    It seems that sometimes pressure bleeder is not absolute, so maybe try doing it the old fashion way to see if it works before u spend big money on the booster and the master cylinder. Hopes this helps

  6. #6
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    Quote Originally Posted by Critter7r
    Are the new front calipers OEM or aftermarket? If they're not OEM, they may hold the pads slightly farther away from the rotors, and that distance has to be taken up by pressing the brake pedal farther.
    Not necessarily. Because if your theory is correct then anytime a brake pad starts to wear your brake pedal would need to travel farther And farther. The problem now seems to be the a sponginess feel. This wouldn't make A difference but what new brakes Re you running?

    When I changed my front brakes to stoptech bbk with stainless steel lines, I also used a pressure bleeder and thought I got everything out. The brakes where still spongy and took the longest time to figure out why that is. After much searching I decided to pump he brAkes while the car was off, open one of the bleeder valve and again press on the brakes hard. After that a couple small bubbles came out and the brakes are working perfectly again.

    It seems that sometimes pressure bleeder is not absolute, so maybe try doing it the old fashion way to see if it works before u spend big money on the booster and the master cylinder. Hopes this helps

  7. #7
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    Quote Originally Posted by Critter7r
    Are the new front calipers OEM or aftermarket? If they're not OEM, they may hold the pads slightly farther away from the rotors, and that distance has to be taken up by pressing the brake pedal farther.
    Not necessarily. Because if your theory is correct then anytime a brake pad starts to wear your brake pedal would need to travel farther And farther. The problem now seems to be the a sponginess feel. This wouldn't make A difference but what new brakes Re you running?

    When I changed my front brakes to stoptech bbk with stainless steel lines, I also used a pressure bleeder and thought I got everything out. The brakes where still spongy and took the longest time to figure out why that is. After much searching I decided to pump he brAkes while the car was off, open one of the bleeder valve and again press on the brakes hard. After that a couple small bubbles came out and the brakes are working perfectly again.

    It seems that sometimes pressure bleeder is not absolute, so maybe try doing it the old fashion way to see if it works before u spend big money on the booster and the master cylinder. Hopes this helps

  8. #8
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    Thanks for the replies.
    Quote Originally Posted by Critter7r View Post
    Are the new front calipers OEM or aftermarket? If they're not OEM, they may hold the pads slightly farther away from the rotors, and that distance has to be taken up by pressing the brake pedal farther.
    The calipers are aftermarket actually (NK brand, made by Scandinavian Brakes Systems) but were meant to be a direct replacement for OEM!
    Quote Originally Posted by EURO M3 CSL View Post
    Not necessarily. Because if your theory is correct then anytime a brake pad starts to wear your brake pedal would need to travel farther And farther. The problem now seems to be the a sponginess feel. This wouldn't make A difference but what new brakes Re you running?

    When I changed my front brakes to stoptech bbk with stainless steel lines, I also used a pressure bleeder and thought I got everything out. The brakes where still spongy and took the longest time to figure out why that is. After much searching I decided to pump he brAkes while the car was off, open one of the bleeder valve and again press on the brakes hard. After that a couple small bubbles came out and the brakes are working perfectly again.

    It seems that sometimes pressure bleeder is not absolute, so maybe try doing it the old fashion way to see if it works before u spend big money on the booster and the master cylinder. Hopes this helps
    I just replaced the OEM setup (324mmx30mm) with new calipers, discs, steel lines and pads, so it wasn't a BBK. The thing is though prior to this, I had already bled the old-fashioned way and it felt the same! So I decided to buy a pressure bleeder and setup a GT1 to vent the ABS valves, just to make sure I was doing it properly. I ran it at about 20psi, didn't get any air out of the brakes but did get some from the clutch slave cylinder.

    I guess it's no harm to try it again though, as you said it's a lot cheaper than replacing the booster and/or master.

    Also, just to clarify, there is only a small amount of sponginess in the pedal. In fact, if I didn't have excessive pedal travel, the slight spongy feel wouldn't even bother me. I saw this chart online, and it is referring to the booster as a potential cause for excess travel:



    Would you guys tend to agree or disagree with it's suggestions? I'm a bit lost at what to do at this stage!
    Last edited by rpg; 08-17-2011 at 02:36 PM. Reason: Automerged Doublepost


  9. #9
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    You have replaced calipers & brake lines hoping to eliminate pedal travel & spongy feel to pedal-have you bled in the proper pattern?observed color of bled fluid(very dark signaling corrosion)? I suggest bleeding manually(two person method)followed by pressure bleed of system. If no improvement,the problem points to master cylinder/slave cylinder.By the way have you done a full system flush of brake fluid?(needed if color of ejected fluid was darker than normal).

  10. #10
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    As far as I am concerned, a "spongy" brake pedal means air in the system, and if the pedal pumps up higher between quick strokes, that confirms it. I've known internally-leaking master cylinders to cause almost "spongy" brakes, but I've never known one to pump up between strokes.

    Similarly, glazed pads/rotors can cause a spongy feeling, and greater pedal travel - but they don't pump up, either.

    On the other hand, did this issue begin with all your brake replacements? If so, are you absolutely sure your new components are matched to your master cylinder's output? This, because your pedal is low; the master cylinder may not be moving the fluid that the new calipers require/ Which makes me say both Critter and EuroCSL are correct. It's not that the pads are being held too far away though, critter, because they will always barely retract. It's just that the ratio of fluid movement between the master cylinder and the calipers may be incorrect, so more travel or incorrect brake balance is likelt to result.

    I use a pressure bleeder on one end, a vacuum bleeder on the other, and when I've replaced components, I throw in a few good hard stabs on the pedal for each wheel, while both systems are operating.
    Last edited by bmwdirtracer; 08-18-2011 at 02:23 AM.

    Chris Powell
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  11. #11
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    Exclamation

    BMWDIRTRACER is on track when he states that a spongy pedal points to air in the system,while excessive pedal travel points to a bad master/slave cylinder.I am at a loss on this one since you have not answered my previous post,Good Luck!

  12. #12
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    Thanks to all for the replies.

    Yes, I bled in the pattern dictated by DIS/GT1 (i.e. begin from caliper furthest away from master cylinder and work towards it), I cycled the ABS valves on each wheel and the fluid was clean as I had only changed it last summer (approx 5-7k miles ago). I replaced the calipers on the front due to badly pitted pistons (and therefore sticking brakes) a couple of years ago and they've been working well since. I can't recall though what the pedal feel was like when I first changed them though unfortunately. It's only over time that I've realised something isn't right.

    The specifications of the NK brake caliper were identical when I checked. I cross referenced the OEM part number and "Manufacturer restriction: ATE" (translated from German) came up also in the notes, so I suspect they're built to OEM specs. The piston bore is 60mm just like OEM ATE calipers.

    OK, I just remembered something, what do you think in relation to this. When I was bleeding the brakes the last time (pressure bleed with GT1 cycling ABS valves) the pedal felt awesome during the bleeding procedure. It was rock solid (no sponginess) and it was right at the top. I remember thinking to myself "Wow, this is going to feel great now" but once I finished the job, lowered the car and took it for a drive, it felt the same as before.

    Thoughts?


  13. #13
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    The only thing I was suggesting with the whole aftermarket caliper statement was (first off- it was just a hypothetical, I was guessing) if say ... the piston o-ring were of a larger diameter, then the amount that the caliper piston retracts after braking would hypothetically be greater. I was just throwing up ideas to get people thinking, since answers weren't really flowing.

    EuroM3: I was in no way suggesting that as the pads wear, they get farther from the brake rotor. Repeat, I was NOT suggesting that.
    Quote Originally Posted by B4SH View Post
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  14. #14
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    I knew you meant what I said, critter, you're always right on the money.

    At this point, rpq, I'd throw a master cylinder at it, especially because of the good pedal during bleeding procedure. Bench-bleed it first. to save time later. Check the insides of the vacuum booster for brake fluid, which will ruin it.

    I am assuming that you're getting good fluid flow from each wheel's bleed screw during bleeding, correct me if that's not true.

    Chris Powell
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  15. #15
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    Thanks guys for sticking with me through this thread, it's much appreciated.

    OK, I think that's what I'll do. I've managed to locate a TRW master cylinder (Part # PML364) for approx $80 delivered so I'm going to buy it. Thanks for the tip about bench-bleeding, I will do that first. I can't seem to find a cheap booster so I'll leave that for the moment. If my existing booster is contaminated with fluid I will look in a local breaker yard first for one in decent condition.

    Fluid flow is OK, I wouldn't say it's fast though. It's slightly better coming out the fronts than the rears. With the nipple open, the flow from the calipers is quite slow with just the pressure bleeder (~20psi), but once I depress the pedal to the floor about 8-10 times, I can get approx 100ml brake fluid into the bleeder bottle (from each caliper).


  16. #16
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    Update - and it's not a good one.

    Fitted a brand new TRW master cylinder today and a used brake booster (came from a '02 530i) from a local breakers. Everything went relatively well, and like before when bleeding it felt good. Took it off the ramps and for a drive... nothing has changed.

    Pedal felt stiff when pumping and bleeding but then when everything came off and put back on the road it's back to the way it was before i.e. excessive travel. I can pump it up three or four times and it will feel solid for a second, but if I hold the pedal in position, it just slowly drops halfway down (doesn't reach the floor).

    I really am lost at this stage. Any suggestions appreciated. Also, my 3 brake lights are on all the time now, The 2nd I turn on the car they go on and won't go off. But I'll fix that I'm sure, as it was working fine before hand.


  17. #17
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    Unfortunately for you, brake boosters cause excessive effort/a very hard pedal. Not excessive travel. That was a waste of money.

    Did the pedal feel spongy with excessive travel before pad and rotor replacement? It's possibly soft frictional material is slightly compressing when force is exerted, giving that spongy feel. I've also heard of instances where they develope a tapered wear, causing the pads to shift a bit when applied and pedal feels spongy.

    Also, I have a question. You say while you are bleeding, the pedal feels firm and is at the top. When you go for a test drive, it feels spongy with excessive travel. Are you bleeding with the engine off and feeling a firm pedal, and then starting the engine and feeling a soft pedal? That would only mean that the brake booster was working, and again was a waste to replace.

  18. #18
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    Quote Originally Posted by jriv View Post
    Unfortunately for you, brake boosters cause excessive effort/a very hard pedal. Not excessive travel. That was a waste of money.
    Quick, and to the point. To be honest the master cylinder was the real job today, I only replaced the booster as it had to be removed anyway and I got it for 30 odd quid, so not too much of a loss!
    Quote Originally Posted by jriv View Post
    Did the pedal feel spongy with excessive travel before pad and rotor replacement? It's possibly soft frictional material is slightly compressing when force is exerted, giving that spongy feel. I've also heard of instances where they develope a tapered wear, causing the pads to shift a bit when applied and pedal feels spongy.
    That's a good question, and unfortunately I can't remember. The pedal was never right at the top, but I don't think it travelled as far as it does now. Discs are not OEM, nor are the pads. The pads are EBC YellowStuff, they're a fast road/track pad.
    Quote Originally Posted by jriv View Post
    Also, I have a question. You say while you are bleeding, the pedal feels firm and is at the top. When you go for a test drive, it feels spongy with excessive travel. Are you bleeding with the engine off and feeling a firm pedal, and then starting the engine and feeling a soft pedal? That would only mean that the brake booster was working, and again was a waste to replace.
    Yes, bleeding with the engine off. Are you alluding to the fact that I may actually be experiencing normal brake system function??

    Can I bleed with the engine on? I'll try anything at this stage!


  19. #19
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    The point is the reason it is firm and to the top is because the brake booster is not able to operate with the engine off. Here, see for yourself. Cut the engine off, and then pump the brake pedal several times. You will notice the pedal gradually getting hard. We could have chased an anomaly that doesn't exist! Was already breaking out my theories considering pressure differential when using pressure bleeder vs atmospheric pressure

    Now that you tell me they are race pads and rotors, I have another expirament for you. Try getting them hot, take the vehicle for a nice joy ride and put your brakes to work. I wonder if these pads true characteristics are when they are smoking hot, and here you are playing with it while it is cold, damp and unexcited! Haha take it for a test drive and let them heat up a bit, come back and tell me if that makes a difference in pedal feel whatsoever.

    I doubt how that would effect pedal travel too much but I'm not exactly sure what your definition of excessive travel is. Perception is everything so lets start with the basics and maybe we can help you come to a conclusive solution.

  20. #20
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    Oh, hell. I mentioned this early on, but it got away in the search of other things. Um, did you follow a good bedding procedure for the new pads? Hard pads require a thorough bedding, and I'd have to wonder whether you've just glazed the pads and rotors?

    You might like to go scuff the rotors and pads with 120 grit sandpaper, and rebed them gradually, and 'til they've been fully hot.

    Chris Powell
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  21. #21
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    Thanks for the replies guys, but I'm very close to giving up on the whole thing.

    When I got the pads initially I found it very difficult to bed them in properly on the road, and as a result was experiencing brake judder/vibration through the steering wheel. Once I brought the car to a track and gave them a good run-in, the judder disappeared and they felt better.

    My definition of excessive pedal travel is 2-3 times the travel of that of a 'normal' car. My father's GS450h for instance bites right at the top of the pedal, mine travels nearly three times that distance before it bites. When it does, braking power is good however, there are no issue there. I guess you could say because it takes so long to bite, that it's 'spongy' up until that point.

    I don't know, maybe it's a combination of the new calipers, pads and discs (none of which are OEM) but I think I'm just going to have to live with it. I have been contemplating a new front brake setup for a while now (as my 530i is S/C'd) so maybe I'll just wait until I do that.


  22. #22
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    Every (newer) nissan I ever driven had very little pedal travel before the pads grab. Nearly throw myself to the windshield everytime I step on the brakes lol. There might not even be a problem if you are comparing it to that, I still think your perception of excessive travel is different from mine.


    If it doesnt feel excessive to the point it seems dangerous to drive on highways, but as you say brakes well then it may be normal on your vehicle.
    Last edited by jriv; 09-09-2011 at 11:08 AM.

  23. #23
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    Had similar issue, now resolved.

    Quote Originally Posted by rpg View Post
    Thanks for the replies guys, but I'm very close to giving up on the whole thing.

    When I got the pads initially I found it very difficult to bed them in properly on the road, and as a result was experiencing brake judder/vibration through the steering wheel. Once I brought the car to a track and gave them a good run-in, the judder disappeared and they felt better.

    My definition of excessive pedal travel is 2-3 times the travel of that of a 'normal' car. My father's GS450h for instance bites right at the top of the pedal, mine travels nearly three times that distance before it bites. When it does, braking power is good however, there are no issue there. I guess you could say because it takes so long to bite, that it's 'spongy' up until that point.

    I don't know, maybe it's a combination of the new calipers, pads and discs (none of which are OEM) but I think I'm just going to have to live with it. I have been contemplating a new front brake setup for a while now (as my 530i is S/C'd) so maybe I'll just wait until I do that.


    I wanted to resurrect this thread to hopefully help others encountering this problem.
    I was experiencing the same issues after a recent caliper swap out. Excessive pedal travel. Similar spongy feel. I had plenty of braking power when the pedal finally engaged. I also noticed that the car was not pulling to one direction or the other while braking, which I have noticed in the past when dealing with air in the brake system on pervious non-BMW vehicles.
    It turned out that the problem was actually quite simple and perhaps easy to overlook. The SPRING CLIP on the new caliper was not installed correctly. Apparently there are two ways you can install it and have it stay in. The way it was incorrectly installed did not provide enough tension to prevent the caliper piston from retracing too far back inside the caliper. This caused all the symptoms and I could visually see excessive movement while my helper engaged and released the brakes. Reinstalling the spring clip correctly solved all the issues and the car was back to normal at no cost.

    I hope this helps someone else down the line. It can really boggle your mind for quite awhile thinking of all these complex possible problems that may or may not fix it. I felt foolish for installing the clip wrong but overjoyed when discovering how easy it was to fix.

  24. #24
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    Are you talking about the spring clip that keeps the outer pad from rattling? I'm having a hard time picturing how that clip would limit the lateral movement of the caliper.
    Quote Originally Posted by B4SH View Post
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    Quote Originally Posted by fcvapor05 View Post
    Do you even OT? The mean 401k around here is probably about $6, what with all the shiny cars and $1,000 watches and donations to get other members' Volvos running.


  25. #25
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    Same issue here that OP has. Bought my 2002 530i with 75k miles a month ago. Had spongy pedal but had aftermarket drilled/slotted rotors and who knows what pads and who knows how old the fluid was. I rebuilt the calipers, installed Zimmerman rotors, Akebono ceramic pads, FCP brass/SS slider pins, FCP SS flexible lines, and pressure bled and buddy-bled brand new ATE Super Blue fluid. Same brake feel after bedding the pads in with 10ish 50-10mph hard decelerations. Took it to my local BMW specialist shop and had them bleed it as I thought I might have introduced air into the ABS pump. They bled it with their BMW computer diagnostic system (activates the ABS pump) and bled it another way (not sure if buddy-bleed or pressure) and pushed through two more quarts of fluid. They said there is 0% chance any air is left in the system and I believe them. The owner was my service writer and he said he's driven the E39 on and off since they came out and the pedal should NOT feel like this. They even thermal imaged the brakes and found that the heat signatures and differentials were appropriate, indicating that no caliper was sticking or slow to engage/disengage. I replicated this with my infrared thermometer and came to the same conclusion as well.

    - With car off, the pedal is rock hard.
    - With car on, the pedal engages relatively early, but requires most of the travel to get full engagement, it seems a the braking force gets exponentially stronger as i push, but it's not that far off of a linear pressure application.
    - If I pump the brakes with the car on, the brakes DO NOT get better
    - brakes will engage strong enough to engage abs

    The shop said this does NOT seem like it is a master cylinder issue. I agree as if that were the case the pedal would continue to travel as fluid leaks out of the cylinder bore back into the reservoir or externally.
    The shop said this does NOT seem like the sometimes occurring contaminated brake booster issue, as mine is not full of water and I don't get any 'slushy' sound when i engage the brake pedal. My car runs fine aside from a very slightly erratic idle when cold. And if it were a booster issue, wouldn't the braking effort get GREATER?
    The shop said there seems to be no issues with any of the hydraulic lines as they can inspect them as well the brake thermo-imaging indicates all four corners are working properly related to one another.

    I do have a missing caliper pad clip on the left rear, which I will replace, but I would tend to agree with Critter that this doesn't seem like a likely culprit. I have a new set of rear clips on order and will install those this weekend. Fingers crossed I guess since I have no other idea what could be wrong here.

    The shop did suggest I buy some OEM or good semi metallic pads and install them dry, start the car, and apply the brakes. If the pedal feels better, ditch the Akebonos. If the pedal isn't better box them up and return them. They agree the Akebono ceramics don't offer the most positive engagement, but have never installed them to find they result in this type of symptom.

    So not much help here, just another E39 owner with a very, very similar situation as the OP.
    Last edited by frknvgn; 11-03-2016 at 05:03 PM.

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