AP12001

my friend's GPW has a slight braking problem.. i test drove it with him and 80% of the time, the brake travel feels fine and it stops just right.. the 02 car has 56k miles in it and have never been in an accident since he is the first owner of it

however, 20% of the time, when i go to brake, whether it's a hard brake or just a slight brake, it feels that something is 'grinding' and the pedal travel down being depressed is not smooth.. like something is preventing it from going down fully.. and it feels like the brake pedal is being 'moved' and 'wiggled' .. it's really hard to explain unless you drive his car.. again, this only happens maybe 2 times out of 10 when braking, hard or gentle..

have ANY of you guys experienced this before in your S? i suggested to him to have his brake lines flushed, add new brake fluid in, change brake pads, and maybe it will go away.. but maybe you guys can help him out a bit.. (xviper i hope you read this and hopefully know a reason why)

my friend will chime in later on as he is currently at work, but i thought id get this started now so he can fix it in time for HIN in Atlantic City this weekend thanks in advance guys.

HiPER

The rotors may be warped.

xviper

An '02 with that kind of mileage should have had the brake fluid flushed and changed if it hasn't been done by now, so doing it is not a bad idea anyway.
The "20%" of the time is interesting. If you had warped rotors or bad brake pads, the other 80% of the time would not be much different.
A couple of things ......................
1. When the car is being driven down the road at any speed, no brakes being used, is there a squealing noise? This would indicate that the thin pad indicator is telling you that the pads need changing. If the answer is "no", then it's not likely in need of new pads.
2. Do you guys know what the ABS pulsation feels like? It's a sort of ticking sound which can be felt through the pedal. A hard application can easily cause the ABS to activate. A mild to soft brake application can also activate the ABS if the road surface is conducive to easy wheel locked up. Some of these can be bumps in the road (regardless of speed, but more apparent at slow speeds), loose debris like leaves, sand, heavy dust, wet, oil, etc. By any chance, were these conditions encountered during those 20% times? If so, then this is normal.
3. Once you determine that the brake fluid is good (changed) and #1 and #2 do not apply, then it is possible that the master brake cylinder could be scored and will require replacement. However, this generally (but not always) accompanied by an unusual drop in brake reservoir fluid level. How's the level?

Just a freaky thought .................... Have you checked the brake pedal area to make sure that nothing (like the floor mat) is getting in the way of the pedal movement?

AP12001

in regards to xviper's comments:

1) there is NO squealing noise

2) as far i can remember, there was no pulsation or ticking sound felt in the pedal during the 20%

3) my friend said he will check the brake fluid as soon as he gets home tonight (s2k is his garage queen)

freaky thought) yea, i checked it when i drove it.. there's nothing there to get in the way..

i shouldve mentioned that it seems that i have to depress on the brake pedal a whole lot deeper compared to my S when it comes to braking.. when i felt that, i was going to say that his pads were shot.. but then that doesnt explain why 80% of the time it brakes fine while 20% of the time, there is a grinding feel on the pedal and you can feel a slight vibration on the pedal itself

so in summary:
80% of the time: braking is fine, you just have to depress pedal deeper than normal
20% of the time: some 'grinding' and 'vibration' can be felt by the driver thru the pedal..

please, anyone who might have had experience like this.. please come thru with your thoughts and suggestions.. we would appreciate it very much.

xviper

Deep pedal travel would be an indication of air or water in the brake fluid. I think it's time to change the fluid and check the pad thickness while you're at it.

AP12001

thanks viper. ill recommend both the brake fluid and brake pad change and post up here again of results afterwards.

AP12001

my friend said that he has various new symptoms...

1) his ABS light goes on when the car is started and on idle.. then when he starts to roll above 20-25 mph, it turns off by itself.. then when he is at a complete stop, it turns on again..

2) when decelerating free rolling while on neutral, he hears clicks around the brake pedal area.. also, if he was to decelerate using the brakes, he would feel some 'griding' and 'vibrating' actions by the brake pedal..

3) after 10 minutes of just normal driving, he claims there is a 'burning' smell coming from the calipers and wheel well itself (specifically the driver side)

can anyone help or know of why these things are happening?

xviper

You should really get your friend to register here and post up his "first hand" comments. You are leaving out too many details that make for diagnosis impossible.

For ex...............

When starting up, what's the idle rpm and for how long does he idle?
You say burning smell from the calipers ................ which one? front? back?

See, this is just going around in circles. Just get him to post up ALL the details. I'm not willing to play "20 questions" and a guessing game.

soundzero

check your pads, rotors and brake fluids.

Am I missing anything?

dewke

I'd have your friend take his car into a garage and get his brakes looked at.