Vibration/rumbling whilst braking... Again.

[Wildfire]

So I had the Z out today, hit the brakes at motorway speeds and got a rumble from the front.

Now last time I had this it was warped discs and worn lollipop bushes.

That was 5k ago. The bushes are fine, but it feels like the discs have gone again.

Anything/anyway I should check tomorrow?

 

[Dogmatic6]

So I had the Z out today, hit the brakes at motorway speeds and got a rumble from the front.

Now last time I had this it was warped discs and worn lollipop bushes.

That was 5k ago. The bushes are fine, but it feels like the discs have gone again.

Anything/anyway I should check tomorrow?

Sticking caliper? Usually N/S front. Check for a hot disc on one side

 

[Wildfire]

Yep. Now when I spin the O/S front I have a faint rubbing sound at one point in the disc. Same place every time.

Anything I can do? Or do I have to replace or skim the disc?

 

[MrPT]

Take your calliper off and have a look at it. If the piston is off angle or the seal looks damaged or deformed in any way, then get it refurbished (about £30 for a refurb kit or £50 for a trade-in for your old calliper from somewhere like eurocarparts.com).

If the calliper looks in reasonable shape, try and use a clamp or rewind tool to push the piston back in. You might need to take the top off your brake fluid reservoir to do this, but be careful that it doesn't overflow. If it doesn't retract with a moderate amount of pressure then, again, you should get it refurbed or replaced.

It is possible that you have warped the disc, but it's more likely - especially if it's the N/S front left (and also if you have high carbon discs) - that your calliper is dying and the back pad is rubbing on a very thin lump of material on the disc because the piston hasn't fully retracted. I just had my N/S calliper seize recently and it wasn't very fun - the wheel got so hot that that BMW emblem became soft enough to fall out.

 

[Rory]

Im trying to rid my car of brake judder at the moment too, very annoying. I had it about a year ago and when checked with a temperature gun I could see one front was hotter than the other - so changed that caliper and problem sorted.

Now all of a sudden I have a judder back , checked temps of all wheels and all the same but assumed the other front caliper would be away so I changed it yesterday. The seals were gone and it was full of rust so couldn't have been working properly - but took car back out and theres still a judder.

Now not sure if its a back caliper as the temps have been the same