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pad wear uneven

Discussion in 'E36 M3 (1995-1999)' started by tjrinaldi, Oct 6, 2010.

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    tjrinaldi

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    Hi Guys,

    I have noticed distinct unequal brake pad wear between the drivers and passenger front brakes on my '95 M3. The car is maintained well and has now seen the track enough for me to begin noticing a slight pull under heavy braking.
    Upon removing the Pagid Red pads from Bav Auto to install my race pads I noticed more wear on the DRIVERS side pads. Now after one track day the Hawk Blue pads exhibit the same trouble. It is not extreme, but just noticeable. New rotors are always used with new pads, so culprits at this point are calipers, lines, or otherwise. Upon heavy braking the car does pull to the DRIVERS side. When I installed the newer pads I do remember considerably more effort was needed to compress the PASSENGER piston. It could have been because I was compressing unevenly, but now I wonder...
    Also, the rubber brake lines up front are starting to dry rot and they will need replacing. My questions:

    - should I replace with stainless lines to eliminate unequal line pressure or are new rubber ones sufficient?
    - should the calipers be rebuilt, or does this sound like a line problem?
    - should I install the solid metal caliper guide bushings now that I am on the track more, or are the standard ones sufficient?
    - am I completely missing something here by not looking at the master cylinder or outgoing lines?

    Thanks in advance for all the help!

    -TJ Rinaldi
    Badger Bimmers
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    steven s

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    My guess is dirty guide pins. You may want to replace your bushings since it's so easy and cheap.
    I would not recommend the solid bushings since they tend to get dirty unless you are only using the car for the track and can inspect them regularly.

    If that doesn't work, I'd have the calipers rebuilt. Just looking to do the cheap stuff first.
    That is on my must do before my 1st 2011 DE.
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    MGarrison

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    Stainless lines front & rear are pretty much a no-brainer for track driving. If your stock lines are shot, replace w/ stainless all around. Cheap enough to rebuild calipers, maybe start there, perhaps you cocked the piston in the caliper slightly. Inspect the lines completely from front to rear and make sure they're not rusted. The guide bushings should minimize pad deflection yielding uneven pad wear, but afaik, stock ones are fine. If you get the guide bushings, make sure your slides fit before installing them. After a bazillion pad changes, the ends of my slide pins on the rears (where the hex socket fits) had deformed slightly, making it slightly larger dia. than original, and enough to jam in the metal guide bushings.

    Although large calipers are quick, I use pad backing plates saved from worn down pads and a brake pad spreader (http://www.sears.com/shc/s/p_10153_12605_00994206000P?prdNo=15) to push pistons back in. Takes a little longer, but pushes the piston back in with even pressure; Since the pistons are cupped, using a pad backing plate (any flat piece of metal long enough will work) insures I don't run out of travel with the spreader and pushes the piston in completely.
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    steven s

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    It's debatable whether s/s lines are worth it. I'm replacing mine with rubber hoses next time.
    That is probably for another thread.
    One of my solid bushings binded and that is why I no longer use them.
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    MGarrison

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    Debatable... well, perhaps. Bimmerworld's $119 price for a set of lines (ok, so shipping's gonna be a few bucks more) is a fairly inexpensive mod to add some additional insurance that he's gonna haul the car down from the likely near 150mph an E36 M3 might get to on the back straight of Road America into Canada Corner. Even factoring in the labor expense (or hassle, if diy), assuming no extraneous expense due to mistakes or damaging a metal line, I'd take ss lines everytime - particularly if Road America was my home track. Compared to the cost of having an off track incident involving body damage, due to brake fade, installing ss lines would be comparatively insignificant, imo.
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    tjrinaldi

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    so far turn 5 is what scares me most...almost ate it last Saturday when the car did pull upon heavy braking....hit darn near 130 mph on the 3-5 straight....don't know exactly because I was concentrating on the turn!!!

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