E30 Zone

Hi, I am still wrestling with various weird rattles and clonks at low speeds from the rear of my car - 1990 320i cabrio. Having changed arb drop links and shock top mounts without any improvement I have checked the exhaust - all seems sound but now I've noticed something else that may or may not be linked - in fact I'm not even sure it's a problem at all but I havent noticed it before so thought I'd ask...

Handbrake on, engine running, into first, a few revs so it doesnt stall, and slowly bring the clutch up leaving the handbrake on - car moves forward about an inch, then stops and rear suspension drops as if the handbrake is holding it (as it should). But why does it move in the first place? I have had a look under whilst this is happening and there's no obvious movement on the rear subframe bushes or diff and the rear propshaft joint is definitely moving with the gearbox so I guess that means the doughnut/guibo is ok.

Had new rear discs fitted a few months back and I want to make sure they are working as they should apart from wondering if this is linked to the clonks. No problems with the handbrake holding the car incidentally.
Thinking about it I guess it could just be that the handbrake is working much more effectively on one side than the other...?

Any ideas or experience of this?

Cheers

your handbrake shoes night have fallen to pieces and they might be jamming uo the wheels after that slight bit of movement?

Handbrake on, engine running, into first, a few revs so it doesnt stall, and slowly bring the clutch up leaving the handbrake on - car moves forward about an inch, then stops and rear suspension drops as if the handbrake is holding it (as it should). But why does it move in the first place? I have had a look under whilst this is happening and there's no obvious movement on the rear subframe bushes or diff and the rear propshaft joint is definitely moving with the gearbox so I guess that means the doughnut/guibo is ok.

Common (ish), have read of a few others having the same thing, inc me!

99% sure its not bushes, i jacked the whole rear end up and with the handbrake on i could rotate the wheel in the way you describe, its almost like the whole inner handbrake assembly is moving!

Cant be that bad as it never got a mention from the MOT fella!

Sure i read its due to the way the adjusters are set.......

Matt

Oh and if your handbrake is set unevenly one side will rise more than the other (car in reverse, handbrake on etc)

HTH

Matt

Small amount of movement like this is normal.
You say the rear discs were replaced recently. Did whoever did it know/bother to adjust the handbrake properly? I.E. Not by just tightening up the handbrake cables!

Damon Hill (dealer) so I hope they would have set the handbrake shoes properly. Less than 1000 miles since. I havent checked this or the cable adjusters yet though.

I'm just wondering whether the rear end rattle I am getting could be due to something loose/detached in one of the handbrake mechanisms. I'm going to do the "reverse slowly and gradually put the handbrake on" trick this weekend to get an idea if both sides are actually working.

Thanks everyone for your help so far, it's really appreciated.

I'll let y'all know what I find...

Cheers

As Brian said the shoes move slightly when the brakes on.
Most cars with rear discs can be rocked back and forth about an inch due to the shoes moving away from the stops at the bottom.

As for the noise, i've re-newed the springs that hold the shoes in place and it still happens.
I didn't bother to replace the shoes though.

Hi

Checked today - handbrake defo working evenly. Comes up 4 to 5 clicks and bites the same both sides, when fully on with the wheels jacked up you can easily move both wheels by about an inch at the rim back and forth, then they stop with a clunk. I am guessing this is the movement in the shoe sthat various people have mentioned and that is no problem. Cables adjusted so there is about 1 inch of tread showing one side one side of the handbrake and 3/4 inch the other. Seems the dealer got it right.

So - that's not the cause of the rattle I get then - I thought shoes may be loose/detached etc. While underneath I checked the front prop coupling which looks ok - minor surface cracks around the bolts but overall healthy.

I AM gonna find out what this mystery clonk/rattle is though. After changing or eliminating the bits I have, I am left with:

Rear arm bushes - look ok to me - but are original
Subframe bushes - again look ok and were changed 5 years/ 20000 miles ago
Exhaust - looks ok and I cant recreate the noise by moving it about. All mounts solid and in place - although the one by the front of the diff looks a bit stretched.
Shock absorbers - not leaking and working ok although there could be some internal source of a rattle?
Prop - rear uj or centre bearing??
Diff mounting - looks a bit manky although from what I have read, these rarely fail and I cant detect any movement here.

The mystery continues. I think I am just gonna try and forget about it for a bit, but it's soooo irritating!

Haven't looked back through the thread to see if its' been mentioned before, but there's no mention of the most common cause of E30 rear end rarrles in that list - the shock absorber top mounts.

Yes they were the first things I changed Brian - from previous service invoices I noticed that the wrong ones had been fitted a few years back (the ones for a convertible are different from the saloon) so I got a pair of the right ones and stuck them on. Made no difference though. Neither did changing the anti roll bar links. The thing is, although I can hear the rattle whether in or out of gear, usually when going slow and whether straight ahead or turning, sometimes the first clonk of the day comes even before the wheels have turned, when I start the engine. It's a very weird thing and I'm sure it's something very simple, but I am gradually eliminating stuff.

I'm sure I've read somewhere (possibly on the BMW Car Club site) that shocks can rattle. I am going to try to find that thread now.

People have lots worse to put up with...

Thanks for your help anyway.

Found the quote I was looking for .... on the BMWCC site -

If the top seal dries out on the shocks, then this will give you the same sort of noise.

Quite a lot of suspension noise is down to shock absorbers, being either dry seals or worn inner bushes although no leaks are visible.

Is this just one person's opinion, or would others agree? I guess there would be other symptoms if shock absorbers were suffering in this way?

have you checked to see if the handbrake shoes are fixed to the back plate?

Well I did check that the handbrake is working as it should - see earlier in the thread. I assume that if the shoes weren't fixed to the backplates correctly the handbrake wouldnt work?

Cheers anyway

Splod wrote:Found the quote I was looking for .... on the BMWCC site -

If the top seal dries out on the shocks, then this will give you the same sort of noise.

Quite a lot of suspension noise is down to shock absorbers, being either dry seals or worn inner bushes although no leaks are visible.

Is this just one person's opinion, or would others agree? I guess there would be other symptoms if shock absorbers were suffering in this way?

New one on me.

Splod wrote:Yes they were the first things I changed Brian - from previous service invoices I noticed that the wrong ones had been fitted a few years back (the ones for a convertible are different from the saloon) so I got a pair of the right ones and stuck them on..

Weren't E46 cab shock mounts were they?
They're a direct replacement for E30 ones and much longer lasting.

Defo E30 parts Brian - 33 52 1 132 104 which are apparently uprated for the cabrio and if you fit the saloon ones 33 52 1 128 819 they dont last at all I am told because of the weight. Interesting about the E46 ones though.

I think the exhaust mounts are the next thing to eliminate. Although I cant make the exhaust rattle (even if I sit in the car and get my son to wang the rear pipes about I cant hear any noise) the centre mount (rubber ring roughly under the back seat) looks stretched (and it's a cheap thing to change). If that doesnt work I will change the rubbers above the rear box.

Thanks for all your help - I guess we're all submerging for the week now.