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a search revealed no help…
I’m getting a little burp/short pulse in the pedal towards the end point of braking. Doesn’t matter if its soft or hard braking. Kinda feels like it burps/farts/hiccups (choose lol). I haven’t done anything reccently except change out the front R ABS sensor. No leaks or anything loose. 87 325is
Any thoughts???
Thanks for your replies!
I’d guess non homogeneous pad deposits on a rotor. Go do a session and make sure you brake hard as heck. That usually fixes pad deposit problems.
yes on the RF.
I also just installed new tie rods and touched the rotors during with dirty hands. I’ll heat em up tonite and see if it goes away… HOPE!
Thanks!
ps: when it “burps” the pressure in the pedal drops about 1/2"+/-, almost like it releases for a split sec. Makes a short light grown sound. The feel is very simular to the ABS engaging.
That almost sounds like it could be ABS firing, but the pedal shouldn’t move that much from ABS. I think I’d be more suspicious of the brake booster.
Get the car out on a wet parking lot and get into the brakes until the ABS activates. If the ABS fails to work at all more testing is possible. If the system is working correctly you’ll be able to feel the left and right fronts firing, usually the right front will fire first. Both rears are on a single circuit, so they will activate at the same time.
Other than checking for leaks there’s not much checking you can do for the booster. A stiffer than normal pedal or a change in pedal reistance while breaking can be a sign of a failing booster.
ok just did test in the rain. The abs seems to be working fine and pretty sure it’s not a pads issue.
I’ll try to explain again…
With just regular braking, towards the end of a stop, the pedal will all of a suden vibrate for a split sec (maybe 1/2 sec max). It makes a grown sound, like abs firing, but lighter and not the same feel when abs really fires. It’s like it releases a burp, strange.
thanks and hope we can figure this out, got instructing at SP next weekend 4-9/10
make sure caliper and bracket bolts are tight, check control arm ball joints for play, and/or replace the rotors. bet it’s just a vibration or harmonic caused by pad deposits.
That has happened to almost every E30 I’ve ever backed out of our shop which is down hill. I’ve never experienced it moving forward though. A quick cleaning of the ABS ring at the hubs and cleaning the sensors has fixed the problem for me in the past.
Do some fault isolation. Disable the abs system and try driving it. If it doesn’t occur, then you know it the abs system.
[quote=“87isMan” post=55906]That has happened to almost every E30 I’ve ever backed out of our shop which is down hill. I’ve never experienced it moving forward though. A quick cleaning of the ABS ring at the hubs and cleaning the sensors has fixed the problem for me in the past.[/quote]Exactly my current experience. I haven’t done anything about it because I know it’s dirty ABS parts at the wheel.
For the OP, I suspect you have the same thing. Waste a can of Brake cleaner front and rear before you do anything else. A light duty wire brush might be nice also.
