Rear knocking - Suicide threat.......please advise

[reddevil]

Hi Guys, my car has just developed a knocking at the rear, I noticed it first while going over bumps but now it also seems to happen when turning left, I have checked and the exhaust seems to be fine, no sign of play in either of the wheels and nothing seems to be hanging off. Any thoughts?.

RedDevil

[reddevil]

Have also just noticed that there is a static sound coming from the speakers when I turn the engine off though this may be TOTALLY not related. Reading through some old posts people mention the rear top mount as a prime candidate for a knocking noise, I know this sounds daft, but how on earth do I check these?, the car passed it's MOT last month and it's pretty worrying.

Thanks again

Red Devil

[reddevil]

Right guys, sorry to repost, but what was a small knocking at lunch has now elevated into a huge knocking. Driving home it sounded like something was rubbing underneath, the knocking speeded up whilst driving and was even there if I dipped the clutch. It is made worse turning left, eases off turning right, but is VERY loud (people were looking as I limped home) so it's loud enough to hear in passing cars even with their windows closed. I can feel a MAJOR vibration under the middle of the car near my driving seat.

To top it all off I was made redundant today after 7 years so I am now skint, jobless and carless....amy thoughts? and please make it a cheap fix.

Red D
Ps. Pass the razor blades....

[dazleeds]

shocker top mounts or maybe axle bushes

but my guess is shock tops mate

vibration in the middle will be the donut mount on the prob

Daz

[Bob_S]

yep prop centre bearing i reakon

[Martinaston]

Sounds like your left rear bush has seperated, so the other side will probably fail soon.
About £8 each but a bitch to fit.

Look up in front of the rear wheel and you should be able to see if its dropped.

[gcorky]

Sounds like your left rear bush has seperated, so the other side will probably fail soon.
About £8 each but a bitch to fit.

Look up in front of the rear wheel and you should be able to see if its dropped.

think Andy had top mounts done or one atleast???defo done drivers side he said

[reddevil]

Anyone close to Teesside who knows what they're doing and can come round and have a look see?, I just don't want to drive it to a garage in case I am making anything worse.

Thanks for the replies Guys

Red Devil

[Alyman]

you can check to see if it's your top mounts quite easily - open your boot and pull aside the carpet stuff at the side so that you can see the top of the suspension tower thing at the back corner of the boot - there might be a rubber thing over the top of the mount (looks a bit like half a squash ball), but quite often they've been taken off and never replaced. If it's there just pull it off. You'll be able to see the rubber mount now - it's got one big bolt on the top and two smaller ones on either side.
When mine started knocking it was obvious right away that they were the problem - the rubber was totally perished and disintigrating. Not too tricky to replace, the mounts were about £7.50 from euro car parts iirc
My car chews through these things really fast (one of the many prices I pay for my lowered suspension!)

[reddevil]

yep prop centre bearing i reakon

I am going to check the top mounts this weekend, but sounds like worst case scenario that it's the prop bearing. Just reading through some old posts, which of these items will need repairing?



Now the next BIG question, if it is the bearing that's FUBAR'D is it possible for a DIY novice to attempt?, I have a trolley jack and 2 axle stands and a socket set, sounds like this is all that's really needed but obviously once I've started to take things apart if I get stuck I will be buggered and the car won't move. Any idea's what a garage would charge me?, obviously I need to save up now, but I will also need my car working.

Thanks for the help so far Guys, really appreciate it.

Red D

[Martinaston]

If its the centre bearing it will do it when you pull away hard and be a repeated knocking and possibly again when cruising at high speed, its caused by the prop shaft swinging out of alignment.

If its just one sharp knock when you pull away try idling along in second gear and then accelerate for a few seconds then come off the power, then keep repeating it. If it does it every time you hit the throttle its the rear axle carrier bush.

If its the shock top mount then as Alyman said have a look in the boot and bounce the car, you should see the top of the shock absorber sticking up through the hole.

Rear bush, part 3
http://www.realoem.com/bmw/showparts.do ... g=33&fg=30
The centre becomes detached, especialy if the MOT guy jacks it up in the wrong place.

[E30BeemerLad]

don't know if it is of any use to you but I have a 325 propshaft in my garage doing nothing, you are welcome to take it away free of charge, but obviously it is in York. As far as I know the bearing is fine on it but no guarantees.

This applies to anyone else if red devil ain't interested. Come and take it away before it gets skipped.

I am not going to fanny about and post it!!!! OK I would for £100

[reddevil]

don't know if it is of any use to you but I have a 325 propshaft in my garage doing nothing, you are welcome to take it away free of charge, but obviously it is in York. As far as I know the bearing is fine on it but no guarantees.

Thanks Mate, really appreciate that and may have to take you up on it once I've seen underneath the car, still slinging it down here so not been under to start demolishing it yet.

The noise coming from my car is constant, it's there no matter what the speed but it slows down as the car physically slows down (not on revs since I tried coasting to stop it, but it continued). Best way to describe it is when kids stick playing cards in the bike spokes, but the noise on mine is accompanied by a BIG vibration and banging near the where the front seats are attached to the floor.

I am reluctant to start ripping the car to bits since I honestly don't know what I am doing (an oil change is a BIG achievement for me to be honest), but intend to have a look in the morning see if it's the top mounts on the rear struts since this seems fairly simply to diagnose, but reading some other threads I am 80% sure it's something to do with the prop shaft (either it's buggered or the centre bearing is).

Red D

[gcorky]

yup sounds like prop from what your saying?

[reddevil]

yup sounds like prop from what your saying?

You mean the actual prop shaft or the bearing or both?

[gcorky]

yup sounds like prop from what your saying?

You mean the actual prop shaft or the bearing or both?

bearing in centre???easy to spot once underneath

[Globulator]

If you do anything to the prop, get a bit of white paint and MARK THE ALIGNMENT so the shaft all goes back together in exactly the same rotational position that it came off from. That includes the attachment to the diff and the gearbox.

While you are there - check the diff bolts (the bolts holding the diff to the car), I think I have heard of these making a racket too if they loosen off.

[mrLEE30]

not too hard to change the prop, only time consuming, and you have basically the right tools. you must remove the middle/rear of exhaust system, remove the heat shield, and you will see the propshaft and centre bearing. read this post too first http://www.e30zone.co.uk/modules.php?na ... ic&t=42242

give it a go worst case is you get it all off and canot get iot back together, but TBH if you can take it a apart thet would be the hard bit as bolts/nuts may be difficult to remove (spray with a load of WD40 first and let soak for a few hours before you start.

you need to pre-load the centre bearing too, i explain it in the above post, and as i say do not split the two halves of the prop without marking them.

AND finally worst case scenerio, you get it apart and get stuck, grab your yellow pages and call a home mechanic, he will come ruond your house and fix it for you, he will charge a couple of hours labour at whatever extortionate rate uk mechanics charge these days!!

it is not too hard to do and home mechanicing can be very rewarding (and sometimes very frustrating! ), and i know you may be skint be invest in a Bentley manual, it will pay for itself within a year if you work on your car at home under the guidence of the manual!!

mrlee

mrlee

[johnna]

Drive to York and get that prop!! The centre bearing is all you need I reckon.

I'll fit it, but you'll have to pay. Time= money and every thing.

[poppit]

Did you get your car sorted?????????????

[fuzzy]

vibration from under the front seats sound like the prop centre bearing for sure.its only about £17 for a new one and its pretty easy to fit if your semi handy with the spanners.ive changed mine 3 times this year so im getting good at it,takes me about 2-3 hours on my drive on axle stands but ive got to remove my driveshafts,diff and drop the exhaust due to my engine conversion.

[reddevil]

Hi Guys, called into a local garage today, he thinks £140-£150 all in would fix it, but obviously until he see's the car he won't know for sure. Still not sure if I should attempt a repair myself, I am far from semi-handy with a set of spanners (in fact I don't own any spanner....lol).

Going to have a think tomorrow, the pleasure of trying to fix it myself, or the ease (but BIG cost) of paying the garage to do it.

Red D

[mrLEE30]

140 quid minus 20quid for parts will buy you a lot of spanners A bentley manual and a few friends who will lend you a hand. you have the axle stands and trolley jack so they are the big items.

get yer hands dirty lad.

mrlee

[wildeian]

Surely the noise would go away after the clutch is dipped if it was the prop centre bearing???

[Globulator]

Surely the noise would go away after the clutch is dipped if it was the prop centre bearing???

No 'coz the shaft is still spinning round, driven by the diff.

[mrLEE30]

Sometimes, and i do mean sometimes, vibration caused by a tranny or engine mount can go away if you dip your clutch but as above if its spinnin its vibrating!!

(you could go for a taller ratio diff to make the prop spin slower = less vibration )

[reddevil]

Hi Guys, just an update, I decided in the end to take it to a garage, I did get under it, but the first bolt I came to was rusted on so I gave up rather than do any damage. £181 all in, this included the fitting of a front prop coupling too as the old one was on it's way.

Thanks for all the help/advice guys, all I got to do now is find myself a job so I can spend more money on the car.

Red D