freddyvette

Anyone seen or heard of these cars get sticky calipers? Slight cyclical brake squeal after braking and releasing pedal while rolling forward.

outhouse

Pull calipers off and clean and inspect

freddyvette

I've done so multiple times. All I can see is the dust boots and faces of the pistons. How can I see if the pistons are sticking?

outhouse

You need to see the sides of the piston. Get them extended further, and they should push in easily with a few fingers.


You may need to disassemble completely and rebuild/inspect.


Bleed complete system at minimum, which another user recently reported helped him for a similar issue.

freddyvette

I've already completely flushed and bled the brakes. They were a bit dirty but no air. How do I push the pistons out without blowing the seals?

Also is there an instructional thread about how to step by step rebuild them?

SupercarFreak

You can remove the caliper from the bracket and use a piece of wood, gently press the brake pedal. Basically, the wood replaces where the rotor was so that the pistons do not get extended too far.

freddyvette

Oh I see. How thick does the piece of wood need to be? I'm guessing about as thick as the rotor?

Also what signs should I look for in the pistons?

Thanks!

SupercarFreak

About as thick as the rotor, you can use your own judgment.

What you are looking for on the sides of the pistons are signs of rust and/or pitting.

From my experience on BMWs, seized calipers are usually the result of torn or dislodged dust boots. This would allow water to sit inside of the pistons, causing them to rust and not move smoothly and freely like they did when new.

SupercarFreak

Is there a reason you think the caliper is sticking aside from the noise you noticed?

Generally, seized calipers are extremely obvious. You will smell the brakes, the steering wheel will shake when applying brakes at highway speed, or the car may constantly pull to one side.

freddyvette

When crawling to a stop after applying the brakes and releasing the pedal, there is a cyclical squeak coming from the brakes that go away when the brake pedal is again tapped and released. I'm quite sure it's something brake related, and since the rotors are brand new and pads have been changed 2 times relating to this problem, I'm going with the issue being the calipers. I don't think it's seized I just think it's worn.

No consistent pull to one side and no shaking either. The only issue that I have apart from the sticking noise is the brakes squeal tremendously after driving it for a few minutes.

SupercarFreak

Interesting. I think you're on the right path. If the caliper is indeed sticking, it will eventually be seized. Let us know what you find out. Good luck!

freddyvette

Yessir, I will check the pistons as soon as I can. I might even just buy new pistons and make it a single trip if someone can direct me to a good set of instructions to do the job right!

dkz

What pads do you have?

freddyvette

Stoptech Street Performance. They squeal like crazy upon light application. I've changed them out twice and they still do it.

dkz

Same thing with mine when i had new rotors and new carbontech pads installed. Never thought about it much so I just kinda lived with it. As for the squeal do a couple hard stops from 60 MPH to 10 MPH without activating ABS.

freddyvette

Is it me or is it kind of hard NOT to activate the ABS?

outhouse

Just driving skill, not hard at all.


Just do some hard braking to make sure pads are bedded in, would be his suggestion.

freddyvette

I have done the recommended break-in on the stoptech website, as well as several 180 to 60 stops on the freeway.

Is this not enough?

outhouse

Not my suggestion bud.



Its hard to diagnose based on what your describing, but if you hear dragging I would probably have the calipers off yesterday and pistons inspected.


If you cannot push the pistons in with only a few fingers, and feel nothing but butter as they go in, then you have a problem.

freddyvette

I should clarify, his suggestion is the same as on the stoptech website.

http://www.stoptech.com/technical-su...-system-bed-in

But I agree with you, the calipers will be inspected this week.