Interesting noise and shimmy...

[e34.535i.sport]

I suspect i need new rear pads/rotors because of the following symptoms:

1. A sound coming from the back thats like someone sharpening a knife pretty much constantly (i only hear it at low speeds though as its not loud and the engine is louder when im travelling at higher speeds)

2. A terrible shimmy when braking from higher speeds - not felt through the steering wheel but in my seat.

3. The rear brakes were giving a little squeak on braking a while back but its gone now?

Am I right?

If so, is this worth doing myself (i.e is it hard) OPTIONS: £120 all BMW parts do it myself or getting it done in the shop (£180 non-BMW parts inc.labour). I'd class myself as rookie/amateur having done oil change/filter, air filter, sparks plugs, fuel filter, subframe bushes, fuel line repair, hose change and interior revamp.

[Podmore]

I'd be pretty sure that your symptoms indicate that your rear pads are worn down to the metal backing plates, which probably means your rotors are going to be damaged. You may be able to get them machined if they are still within rotor thickness tolerance, but given the shimmy they probably are toast. DIY for sure, it's nothing that requires special tools or specialist knowledge. Plenty of help in this and other sites see http://www.bmwe34.net/e34main/maintenance/brakes/pads.htm and http://www.bmwe34.net/e34main/maintenance/brakes/rotors.htm. Good luck!

[mattyb]

If you have been able to do the other things you can do this. First thing is to have a look yourself at the pads and rotors. are they stuffed? common sense should tell you if they are good or not. run your finger over the rotor, is it even? is it so thin you should be worried about it. How are the pads, pull them and have a look? are you getting brake messages on the dash? do the current pads have the sensors? The whole team is here to help so have a look at these things (should take an hour and a few beers) and report back.

Pads and rotors have to become a basic function of your BMW maintenance experience or else you will be paying forever!

If you need any help, just ask.

best of luck!!!!

[e34.535i.sport]

Thanks for the support i'll do that in the morrow and get back to you... I was pretty sure the discs and pads needed changing, but no messages on dash or anything like that. I can't guarantee the sensors are there either really?

It stops well thats for sure, but the shimmy is annoying and a bit scary if you need to slow at 80!

I've been a bit side-tracked as my friend's just bought a car - he got it home and we heard something squeaking in the engine bay. Turns out he needs a new idler pulley (i think thats the correct name!) and some tensioner thingy. Not good but at least he'll save on labour if we do it!


Thanks again, i really want to do the brakes so i'm praying this job goes well...

Will report back soon!

[e34.535i.sport]

I'm back, had a look at both back rotors - no ridges or obvious damage. I think the outer of the discs were generally thicker than the inner, so could this be the problem? I also looked at the pads and tried to feel them but i'll be honest, i don't have a clue what to look for! I asked someone to have a look at them a while back and they said they aren't worn, but they had gone 'hard' ????????? They were squealing then but now they aren't if thats any use.

I think i'm gonna have a go at it before the inspection in september, otherwise it could cost me!

[mattyb]

sounds like it wouldnt hurt to be done, at least youll be braking with the knowledge that they are up to it. As a rule BMW rotors arent ussually machined so dont go ripping them off if they dont ned it yet. Throw a set of new pads on all round and see how they go. get the brake sensor pads if u can. Theres a heap of info here so keep in touch while ur doing the job.

[genphreak]

sounds like it wouldnt hurt to be done, at least youll be braking with the knowledge that they are up to it. As a rule BMW rotors arent ussually machined so dont go ripping them off if they dont ned it yet. Throw a set of new pads on all round and see how they go. get the brake sensor pads if u can. Theres a heap of info here so keep in touch while ur doing the job.I usually swap em all out to be done with it, brakes are a pita to do... I never change pads only- unless the rotors are really good and I don't care abut longevity or perfomance- the rotors normally wear at the same rate on these cars even if they remain legal at change time. It's cheap to do, so one might as well do it right and have truly great brakes, the way these cars are supposed to...

[mattyb]

good advice there nick!!!

[e34.535i.sport]

I think i'll do the lot then (MOT coming up in september!), just need a few more bits then to get the parts from the dealer... I don't seem to have an allen key to fit the caliper bolts? I'll search around tomorrow see what i can find.

A 'pita' to do? Is that bad???? I'm hoping this job is going to go smoothly,! Although when measuring up the job today (underneath looking at what i was letting myself in for), I noticed the stabilizer (anti-roll bar) links need changing... joy!

I'll let you know how i'm gettting on when i finally get around to doing it! THanks guys.

[e34.535i.sport]

Done the brakes, was a doddle. Was worried about it before but its quite straight forward really.

The shimmy when braking is gone which is marvelous! However, the knife-sharpening noise is still there, and i think i need to do the fronts too. Parts from BMW = £176 (pads and discs). Quite steep i'd say...