Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[aaronjb]

I'm ignoring it for now, to avoid all the fun of last time!

The car does almost zero milage at this point (in fact it hadn't moved in so long before the MOT that the battery had gone flat again), and noisy wheel bearings aren't much of a problem on driveway ornaments..

[chrisgixer]

I notice a lot of noise from the back end of my car after fitting the donuts - but I think it's probably a wheel bearing on it's way out rather than anything coinciding with the bushes.. maybe made more noticeable by the change but not directly caused by, obviously.

I had a good deal of noise after fiddling with mine. As it was silent before bush fiddling, then noisy after, closer inspection showed they where not seated properly.

Which suggests checking the bushes first, before oppsing about with wheel bearings. As there might be some slight irritation if the bearing was changed, only for the noise to remain.

[TheBoy]

I can confirm that they are absolutely useless after being subjected to 700-800C for about 40 mins. Sorry Hotel21 

The 2 sets fitted to mine have kept my arse under control, though something has go awol on the Bullet to make it feel like the bush has failed.  However, bear in mind that I am comparing new poly to old, shagged GM ones...

Aye? You have two sets of poly one on each car?

Oui, Monsieur

[chrisgixer]

I have had dome minor issues....

strictly speaking, the rear donuts don't actually fit correctly. I'm still unsure if it's the length of the metal bushing/spacer that's short or the diameter being smaller and allowing it disapear up into the body by x amount.

Result is knocking and clunking under heavy cornering followed by repeated episodes over bumps or on full lock turns. Loose rear end. Plus, I think, wheel bearing type noises if the bolt goes in too far before it tightens. But need to confirm. Presume the bolt is touching the chassis internally and resonating, but as sus need to confirm.

I have added a large washer to the bushing length which has sorted the noises and some of the slop. Plus re fitted the top rubber pad to take up the extra play introduced by the washer.

Time has been the main barrier of getting full answers.

All things area relative though, and the play/slop described is less than that encountered with oe. Certainly no worse.

[Mr Gav]

Strange that, mine fitted perfectly and I`ve not had any issues with the rear end being loose apart from my suspected knackered diff mounts. I fitted the top hats and everything torqued up nicely, just went in as they should.

[chrisgixer]

Strange that, mine fitted perfectly and I`ve not had any issues with the rear end being loose apart from my suspected knackered diff mounts. I fitted the top hats and everything torqued up nicely, just went in as they should.

Let's hope, those dif mounts are indeed buggered then

I think it depends on the position of the subframe. The springs tend to push the subframe rearward. As I understand it. So the holes never line up perfectly. With a thinner/shorter bushing there's less contact area with the body,  which has a slightly recesed area around the bolt hole in the body. Iirc.
I'm wondering if these things conspire to allow the bushing to slip, which would account for some of the noises, given only half of the circumference of the bushing tightens up on the body, going by the witness marks, with the other half over the hole so in contact with nothing. A hole that also has a lip surrounding it if memory serves.
Apply some side load and and that might allow the half clamped bush to slip down the lip.

The when re tightened, the bushing is more centred in the body hole, allowing the bushing into the centre of the hole when tightened. The bolt tightens further into the body above the captive nut, and I suspect, causes resonance. But can't be sure. Although there was certainly road noise at one point that isn't there now with the washer fitted.

Anyone think an LSD is relevant?
I'm thinking drive from both wheels would make the rear axle want to go straight on in a tight turn more than a normal diff. where the body is being pulled round by the front wheels, so puttng more twist/yaw(is that right?) on the subframe relative to the body.

Trouble is I'm knackered and my simple brain is struggling to work out the forces at play this evening.

[chrisgixer]

Just to add I didn't mention. ....iirc the metal sleave/bushing on the polys is about 2mm thick. Where's as the oe rubber bushing is about 7mm. So has much more contact with the body.

[TheBoy]

Just to add I didn't mention. ....iirc the metal sleave/bushing on the polys is about 2mm thick. Where's as the oe rubber bushing is about 7mm. So has much more contact with the body.

Would the end of the insert be used to keep it honest, purely by its friction? But then what else keeps it in place 

[chrisgixer]

Just to add I didn't mention. ....iirc the metal sleave/bushing on the polys is about 2mm thick. Where's as the oe rubber bushing is about 7mm. So has much more contact with the body.

Would the end of the insert be used to keep it honest, purely by its friction? But then what else keeps it in place 

The captive nut has loads of play in its location. (Which I also didn't mention) so while the bolt is tight in the insert/sleave/bush thingy with minimal play, when locating and all bolts are fitted but loose there is loads of play in the whole assembley. The nut, bolt, bush, subframe can all move quite a lot. The springs are, I think, what forces the hole lot rearward.

Bare with me there's a lot of tired thinking aloud here, but the play with bolts loose is more than the thickness of the polys metal insert. And the poly metal inserts can almost fit within the body hole that surrounds the captive nut. UNLESS it's off centre, which it normally is, due to the springs pushing rearward, so then clamps up on the side of the hole.

I'd better go to bed I think, that was bloody hard work.

....but am I making any sense, at all. ?

[chrisgixer]

I need to take it apart again and have a bloody good look. But time is against me until almost Xmas now.

[TheBoy]

So there is enough play (ignoring the friction of the bolt heads on what they bolt against) for it all to move a fair bit? If so, given the massive forces when driven enthusiastically....

The sensation I'm getting is a bit like a flat OSR tyre on sweeping left handers. Not beyond the realms of possibility that I haven't broken another spring - weekend job if I can get the jack from the garage

[05omegav6]

So there is enough play (ignoring the friction of the bolt heads on what they bolt against) for it all to move a fair bit? If so, given the massive forces when driven enthusiastically....

The sensation I'm getting is a bit like a flat OSR tyre on sweeping left handers. Not beyond the realms of possibility that I haven't broken another spring - weekend job if I can get the jack from the garage

Failing shock perhaps

Would taking a 1/4" of the threaded end of the bolt help in case it is tightening against the floor.

Also could the captive nut be welded in place so that it sits centrally perhaps with a washer if applicable...

[TheBoy]

Shock appears to damp OK, but obviously that's not to say its not boogered.

[05omegav6]

Shock appears to damp OK, but obviously that's not to say its not boogered.

Sensible head notwithstanding, could it be a surging effect of the fuel... the petrol tank being off centre to the right, and given Mrs TBs penchant for filling it up...

[TheBoy]

Shock appears to damp OK, but obviously that's not to say its not boogered.

Sensible head notwithstanding, could it be a surging effect of the fuel... the petrol tank being off centre to the right, and given Mrs TBs penchant for filling it up...

No, don't think so. It does feel like oversteer when sweeping that way, but doesn't need any corrections.