knocking from rear end

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bmw9818
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Post Wed Feb 13, 2013 9:54 pm

sooo... another day another issue :cry:

last few days there was a knock from the rear end, and just now its very pronounced,

its more or less under hard accelaration knock knock knock, getting faster with speed....

driveshafts?

i had a look when it first appeared there was some play but not much,

will they fall apart if left for a few months... as no monies at the mo

prop bearing was replaced and torqued down only a few months back, diff is also full of clean oil topped up only a few months back, all trailing arm bolts are tight,

also when i just braked i heard what sounded like a bolt clanging off and dropped on the road.... :?
jimmyspeed
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Post Wed Feb 13, 2013 10:02 pm

could be part of the internal handbrake rattling about , mine are so rusty im amazed they work!

the rear top mounts make a clunking noise at the rear when broken but mine was just intermittent and didn't increase with speed, could be worth a look ?
Jim320i
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Post Wed Feb 13, 2013 10:06 pm

Have you checked the wheel bolts are tight? Sounds daft but an easy one to miss sometimes :mad:
bmw9818
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Post Wed Feb 13, 2013 10:18 pm

lol yep! been there done that :mad: all bolts are tight!
bmw9818
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Post Wed Feb 13, 2013 10:19 pm

will take the discs off and have a look round...
bmw9818
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Post Thu Feb 14, 2013 8:12 pm

can the bearing make that noise? everythings tight,
Sanchez
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Post Thu Feb 14, 2013 8:29 pm

rough bearing is like a grinding noise depending how bad it is.

Its just a case of eliminating stuff till you find the problem.

rear beam bushes?
diff bush?
top mounts on shocks?
trailing arm bushes?
handbrake?
bearings?
loose nuts/bolts?
Image
bmw9818
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Post Thu Feb 14, 2013 9:24 pm

Yeah i was hoping someone would come out with a cheap fix, I fear it's the driveshafts..

Trailing arms are polybushed, Arbs etc all bolts are tight, slights tear in diff bush the thin layer underneath not the load bearing part...

Mounts are e46 m3 new only 4 months ago with an rpm strut brace,
capnmchl
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Post Thu Feb 14, 2013 9:45 pm

Checked your tyre pressures?

Did you put the washers in the correct order for the rear topmounts?

Double sure all the wheels are done up?

Diff bearings not locking up under load?
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Brianmoooore
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Post Thu Feb 14, 2013 11:49 pm

capnmchl wrote: Did you put the washers in the correct order for the rear topmounts?
Did you put the washers under the mounts at all?
bmw9818
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Post Fri Feb 15, 2013 12:01 am

im fairly sure i did, i had the same issue when i first lowered the car, and certain this time i made sure the washer was there, i have curved washer on the top of the mount, and a flat straight washer underneath it sits on a little ledge on the strut then the mounts on top,

at low end upto 2k it makes no noise, then when i boot it it starts knocking faster and faster.

its an lsd and both wheels move in one direction when in the air,

i havent painted an 11 yet, spent about half hour snow drifting in the car park felt as if the diff was locking up nicely, had an open before so i could tell an improvement!
bmw9818
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Post Sat Feb 16, 2013 12:25 am

[youtube][/youtube]



link to a vid... i had another look today all driveshaft bolts are tight ns shaft seems to be a little bit more "loosish" when i shake it than the os...

could it be the shoes ?[/youtube][youtube][/youtube]
bmw9818
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Post Sun Feb 17, 2013 5:37 pm

i now have another noise vibrating up through the gear stick, which i can feel... i got it on the ramp all shafts are tight prop is tight, prop bearings good..
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sparkyE30
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Post Sun Feb 17, 2013 7:49 pm

how does your handbrake feel when you pull it on?
bmw9818
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Post Sun Feb 17, 2013 8:34 pm

handbrake feels fine and feels strong, new cables and set it up perfect,

heres a vid...

[youtube][/youtube]