tibbs.james 1 Report post Posted July 19, 2008 Ok hi All I will start this from the begining. My car has always had a "thud" from the rear suspension right at the back when you apply accelerator sharply. Once i did a manual conversion after a while, it got louder but it seemed ok. Cad was also fitted with a very smooth very clean low kms diff at the time. About 3 months ago, it got so bad i pulled out the rear subframe and did Both subframe and control arm bushings & new shock mounts. This gave the the chance to repalce all the obvious stuff that normally makes clonky bad noises right ? Result was the rear end was stiffer & nicely planted but I still had horrendous clonking thudding noises from the back of the car. It happens when 1) low speed say in 1st gear when applying throttle smoothly to take off nicely ( the sensation is like a learner driver bunny hopping except im not trying to take off in 3rd gear or anything stupid) 2) when changing gear less smoothly than normal ie ( change gear apply throttle & Bang) 3) when you go around a corner and loose a bit of traction ( feels just like a leaf sprung datsun with worn shocks axle tramping ) The noise is deffinatly from the back of the car, rear seat passengers especially notice it. It seems louder on the left hand side of the car ( in my car the left side is the one which loses traction first) Replaced parts are as follows Subframe bushings = New Ireland Engineering Uinits Shock Mounts = New Ireland Engineering Uinits Rear shocks = near new when i bought the car & are still perfect. Rubber Guibo = new from manual conversion second hand parts are as follows Small case Diff > Nice and smooth when turning this over, made no whining or noises or anything, felt super good compared to the diff it replaced. Prop Shaft > universal joint dosn't feel loose or anything like that, center hanger bearing felt like new when it was fitted with manual conversion. Rear Half Shafts > I suspect these all along & I still do but upon removing the complete rear arms this morning they do not feel loose or damagaed when turning overy by hand( Both Sides) PLEASE PLEASE HELP ME I will be Fitting a Med Case 325 Diff & 325 Stronger Axles ect. what happens if the problem is still there? What can I possibly do if the problem comes back ? send the useless car to the crusher ? I totally Love this car to Bits but i simply will not settle for something that makes horrid noises, expereicne tells me that noises like this lead to something breaking which could case an accident or crash and hurt people. Quote Share this post Link to post Share on other sites
togate 0 Report post Posted July 19, 2008 why dont you get a BMW specialist to look at it? Quote Share this post Link to post Share on other sites
kiwi535 538 Report post Posted July 19, 2008 sway bar links? Quote Share this post Link to post Share on other sites
the stig 0 Report post Posted July 19, 2008 That's E30's for you Quote Share this post Link to post Share on other sites
ducatiss 1 Report post Posted July 19, 2008 Is the car lowered and by how much? Really though, you have probably replaced most things so would pay to get it checked by someone in the know. Quote Share this post Link to post Share on other sites
QuickSilver 0 Report post Posted July 19, 2008 Is it just one clunk when it happens? Or a series of clunks? Quote Share this post Link to post Share on other sites
e30plz 1 Report post Posted July 19, 2008 why dont you get a BMW specialist to look at it?+1They'll know whats wrong Quote Share this post Link to post Share on other sites
tibbs.james 1 Report post Posted July 19, 2008 (edited) sway bar links? No rear swaybar fitter Is the car lowered and by how much? Really though, you have probably replaced most things so would pay to get it checked by someone in the know. Lowered by about 25-30 mm at the back Is it just one clunk when it happens? Or a series of clunks? Most of the time its one clunk, but if going at low speed in first or second gear at light throttle it can be a series of clunks Now that the rear cv's axles or whatever are off the car whats the best way to inspect them, they currently still have boots on them. Edited July 19, 2008 by Jimmy Quote Share this post Link to post Share on other sites
Mike 1 Report post Posted July 19, 2008 Sounds like something is loose, either top diff bolts or maybe around the side plates where the subframe mounts to. As you've had all that out it might pay to recheck how tight all that is. Quote Share this post Link to post Share on other sites
bravo 35 Report post Posted July 19, 2008 Diff hanger? Sounds can be really deceptive in a vehicle. Maybe check engine and gearbox mounts in case the whole lot is shifting and making a clunk at the rear. Advice to get someone to look at it is good. You probably needed new bushs anyway, but if you just keep throwing money at it without fixing the problem, you're better off paying the experts. Quote Share this post Link to post Share on other sites
Silver Fox 43 Report post Posted July 19, 2008 I'm with Bravo, check that diff hanger again. Have had a similar experience. Quote Share this post Link to post Share on other sites
QuickSilver 0 Report post Posted July 19, 2008 Aside from all the other solutions mentioned above, When I got mine I was almost positive I had a clunk from the rear, and I assumed it was the diff. It wasnt actually and turned out to be the centre bearing and hanger, it would happen at take off where the prop shaft would spin and hit the bearing hanger, normally described as vibration but this was DEFINATELY a clunk, just a thought? Otherwise the top diff bolt being loose is common and I also had this happen, is it possible that the diff you got may have been fine when you bought it but something happend to it in the meantime? Quote Share this post Link to post Share on other sites
tibbs.james 1 Report post Posted July 19, 2008 (edited) Sounds like something is loose, either top diff bolts or maybe around the side plates where the subframe mounts to. As you've had all that out it might pay to recheck how tight all that is. Needed a breakeer Bar and a long pipe to undo all 4 diff bolts this morning, but ive head the same thing from a lot of diffierent places about diff bolts. I'm with Bravo, check that diff hanger again. Have had a similar experience. Thats very interesting, never got repalced so i guess there is a high possibility it is this, a powerflex one might be in order. It wasnt actually and turned out to be the centre bearing and hanger, it would happen at take off where the prop shaft would spin and hit the bearing hanger Actually as somebody mentioned above if the engine mounts were a bit flimsy that could be causing exactly what you said. Quicksilver to me it sounds whats happening to me might be the exact same thing that you described. so changing a centre hanging bearing thats ok, but are you saying the hanger itself can get damaged and then become non useable ? Quicksilver- I think im going to buy you some beer for that piece of information. Well thanks very much for the help guys- I reckon i might have it under control now. I think getting that propshaft and bearing hanger checked out is top of the list & a new diff hanger soon after. For piece of mind I think that the next diff that goes in will be checked over by speclailist Edited July 19, 2008 by Jimmy Quote Share this post Link to post Share on other sites
QuickSilver 0 Report post Posted July 19, 2008 No worries just sounded like the same as my problem, the rubber inside the centre bearing hanger that I had was almost totally gone and I think this was leaving it too much room and the whole prop shaft would spin at times like take off, or at low speeds and with me it happened especially when going slowly (first gear) uphills, Quote Share this post Link to post Share on other sites
joshnz 2 Report post Posted July 19, 2008 Driveshaft rubber donut thingy? Quote Share this post Link to post Share on other sites
lbirgel 0 Report post Posted July 19, 2008 When I got mine I was almost positive I had a clunk from the rear, and I assumed it was the diff. It wasnt actually and turned out to be the centre bearing and hanger, it would happen at take off where the prop shaft would spin and hit the bearing hanger, normally described as vibration but this was DEFINATELY a clunk, just a thought? How much would this be to fix? ive got the same clunking sound. ive always been told it was the diff. it never happend when i bought the car but it started happening around 6 months ago. Quote Share this post Link to post Share on other sites
bravo 35 Report post Posted July 19, 2008 Centre bearing hanger is around $100ish. If you DIY its quite a cheap fix. Quote Share this post Link to post Share on other sites
lbirgel 0 Report post Posted July 19, 2008 cheers Bravo Quote Share this post Link to post Share on other sites
Yasthil 0 Report post Posted July 20, 2008 No worries just sounded like the same as my problem, the rubber inside the centre bearing hanger that I had was almost totally gone and I think this was leaving it too much room and the whole prop shaft would spin at times like take off, or at low speeds and with me it happened especially when going slowly (first gear) uphills, Hey guys - think i've got the same problem only mine is severe,, at the point where I need to replace the universaljoint or the bearing hanger. Thanks for the info, Ive been stressing out waiting for tomorrow so I can take it to a mechanic. Quote Share this post Link to post Share on other sites
tibbs.james 1 Report post Posted July 20, 2008 For those like myself needing parts I'm going to try this outfit out. Bearing Hanger http://www.pelicanparts.com/bmw/catalog/sh..._pg2.htm#item13 Transmission Mounts http://www.pelicanparts.com/bmw/catalog/sh...M_pg1.htm#item0 Engine Mounts http://www.pelicanparts.com/bmw/catalog/sh...n_pg1.htm#item1 I should get mine soon & I will report back on quailty of the parts. Quote Share this post Link to post Share on other sites
ducatiss 1 Report post Posted July 20, 2008 You will no doubt like me, find the quality excellent. I have bought parts off these guys before and the service and range of parts is excellent. Quote Share this post Link to post Share on other sites
Eagle 1680 Report post Posted July 21, 2008 +1 good communication and good delivery times in just over one week for me Quote Share this post Link to post Share on other sites
