Rear End Thumps and Traction Issues

Philosophico

Member
 S.Wales
Noticed a few problems recently with the Zed....'03, 2.5 sport.


1.
When slowing to a halt, foot off the accelerator and foot off the brake there's a couple of heavy 'thumps' from the back end - sounds like the exhaust is bumping something but it definitely isnt that.
This sound doesn't occur at any other time, neither accelerating nor over bumps.

2.
On right hand turns, roundabouts usually, there's a light scuffing noise coming from the rear left wheel.
Hand a look for loose cables etc and there's nothing obviously rubbing anything.

3.
Fast left hander yesterday and the traction control light started flashing! Holy shite, it was quick but not THAT quick! 8)
Got home and had a look around, noticed that the inside edge of both rear tyres was noticeably warm but the centre and outside edge were cool.


Generally, the back end has a 'loose' feel, more than the usual tramlining.



I've scoured the net and it seems that trail arm bushes is a likely culprit.
Handbrake also seems to be "odd"....sometime its fuln with just a few clicks, other times it has to be pulled up quite high. Wonder if its this or some other suspension bushes that are shot causing the handbrake problem, is the rear axle movement causing it?

I'd appreciate any thoughts and ideas before I hand it over to the mechanics.
 
Sounds like it needs putting up on a ramp for a good look at the tightness of everything and seeing if there is any play or obvious wear. Bushes, bolts, wheels, bearings, springs, shocks, etc. Eliminate al the obvious too of tyre pressures, wheel bolt torque.

Handbrake is actually a separate set of shoes operating inside the rear hubs. Possible they are shot or broken causing odd function.
 
Well, the car's been up on the ramps today.
- only £25 with the local garage...pleased with that...I kept telling them to go back and look again!

Checked over all the suspension front and rear, taken a look at the handbrake and checked the propshaft.
Nothing loose or about to fall off. Apart from a tiny amount of slack on the propshaft all is as it should be :)

Noticed a little weeping on the inner driveshaft rubbers and the diff but hardly anything..."nowt to worry aboot" 8)

The slight scuffing noise disappeared as well, before I took it to the garage :roll:



However, they did notice that front & rear discs and pads need replacing - MOT due next month :(
Anyone recommend any aftermarket discs & pads?

AND, to top it all, driving home I discovered what appears to be the cause of the "thump" noise :oops:
It's the exhaust, popping on the overrun :D
I'm guessing the airfilter needs replacing...will be taking a look tomorrow.


So all in all not a bad result.
Going to have a full suspension alignment done in a couple of weeks to see if the handling can be improved a bit.
I've read that the BMW suspension geometry specifications are "a mile wide"...anyone experimented and found a good
set of figures for the average pot-holed UK road?
 
Check the differnetial bushing... I think that's what it sounds like when it fails.

DSC02622.jpg


(sorry I don't have a pix with the diff mounted)

Here's how the faild bushing compare to the new one

DSC02629.jpg
 
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