Brake Problem

[slippity_slip 0]

Hey all,

About a month ago I bought a 1991 525i. It's a bloody awesome car, but it has a wee problem. When I apply the brakes (at any speed) there is a shudder wobble sort of thing going on, that can be felt in the brake pedal.

Although it doesn't affect the braking performance, it's a pain in the ass and i don't like it much.

The really strange this is, sometimes the brakes are fine. No shuddering or wobbling, just nice, clean braking. (this isn't very often mind you)

The car has been fitted with a set of M3 mags. With the car being a 5 series, this meant the previous owner had to fit a set of hub adapters which he got from Mag and Turbo Warehouse. I don't think this is the problem cos there is no wobble when not braking, though i suppose it's a possibilty.

Anybody else got any ideas what the problem is? Could bleeding the brakes help? For all i know the car is still running on its original brake fluid (now that's a scary thought)

Cheers very much for you input,

Jordan

[E30-323ti 66]

You'll prolly find it is either a warped disc (replace or get machined) or

it will be the bushes on the end of the front suspension arms (the inside rear of the two).

Odd that the wheels needed hub adaptors 'cause those wheels come on a E34 offset.

Unless you have Genuine staggered E46 M3 set of wheels (which would be unusual).

Just FYI, you would need a cert plate to run adaptors or spacers of any kind, so if you don't have one don't have any prang's or the insurance company will bend you over!!

Oh, and welcome aboard

[CaM 0]

I have the same prob on my laurel, also when judt driving, but it's intermittent..

I put it down to the fact that the mags I chucked on it have a larger diamter spigot than the spigot on the hub (hole in centre of wheel) before it was fine, and they balance up perfectly (no dings in rims)...

maybe a set of hubcentric rings (shims that space this gap) would help, but then again, if you have spacers/spacing adaptors, then it wont sit on the spigot anyways..... if your disc was warped then I'd expect it to be constant...

Is it when the brakes get warm/hot that it does it or just randomly? sparkle's e28 does it due to the sh*t pads that turn to porridge anyhting over luke warm....

could be bushes or something, as glenn said as well

process of elimination

[ScD 0]

My e34 does the same thing, but only slightly. I'm pretty sure it’s a slight warp in one of the discs because I can feel a 'pulse' in the breaking force when slowly coming to a stop. I can literally feel where the warp is.

[slippity_slip 0]

My e34 does the same thing, but only slightly. I'm pretty sure it’s a slight warp in one of the discs because I can feel a 'pulse' in the breaking force when slowly coming to a stop. I can literally feel where the warp is.

What you said pretty much sums it up. it's like the brakes are engaging and then disengaging.

Somebody said to me it might just be the ABS, but that should only happen with relatively heavy braking.

Oh, and by the way the hub adapters were certified. It's all legal.

It seems to get worse when the brakes have been used heavily. Suppose this means it is the discs?

Might just get somebody in the know t o have a look at the discs. I'll let you know how it goes.

Thanks very much everybody!!

Edited April 4, 2005 by slippity_slip

[BMW POWER 2]

The discs are definitely warped. Happened to the old E36 3er, must be a BMW problem. Is it an import by any chance?

I think they are around $150 each or something like $210 for both discs, form BMW.

[JasonZE 0]

I just put new rotors and disc pads in my 525i to cure this problem, mine was really bad at high speed braking caused the steering wheel to shudder as well.

As long as the adapters on your wheels are a good fit they will be fine

I personally wouldnt bother with machining the old rotors as they will most likely be close to minimum thickness and new rotors are not to expensive, I could hook you up a good deal if you ever come to christchurch or freight them down, let us know some prices for parts in your area.

[*RJ* 0]

Basically repeating what everyone else has said... I replace my brake rotors and pads in the weekend and the shudder has gone completely. Just gotta to get a new wheel alignment now after I lowered and the car and I should have straight shudder free driving

[slippity_slip 0]

I could hook you up a good deal if you ever come to christchurch or freight them down, let us know some prices for parts in your area.

Thanks mate. I'll have a ring around tomorrow and price some out and let you know.

Thanks everybody!!

Jordan

[kiwi535 538]

the e34 s tend to be hard on the upper control arms or thrust arms,they can cause a shudder when braking,re your adapters they probably dont help,do you have a shudder at any other sped(usually quite a specific band 80- 90 km hr)