Bangs from the rear end when clutching +++

[grr]

I bought my first E34 yesterday, and this is my first post on this forum, so hello to you all. ;-)

This is my "new" car, photo taken yesterday:

http://www.bmwguiden.no/albums/e34_520i/IMAG0035.sized.jpg

It's a good old 520i (1989 - 188.000km/~112000miles), and there's some a few things I need to get sorted out before I'll start using it full time.

First there's this loud banging from the rear when clutching. If I step off the gas before I clutch there's no noises. Any ideas?

And then there's the shaking. The car shakes quite a bit at around 90kmh (~55mph), both with or without the clutch in. The wheels have been balanced and the rims have been checked not to be crooked (the best word I came up with for explaining that, I hope you understand... My bad english excuse: english isn't my mother tongue, norwegian is...)

There's a few other things as well, but these two issues are the most critical.

[Jeff N.]

Questions:

Do you have any driveline vibration? Your banging sound might be a bad transmission guibo (rubber disk in the driveline) or a bad center bearing?

The front shaking is most like thrust arm bushings.

You can read about both these problems in more depth at www.bmwe34.net .

Jeff

[grr]

Questions:

Do you have any driveline vibration? Your banging sound might be a bad transmission guibo (rubber disk in the driveline) or a bad center bearing?
Yep, the whole car vibrates at around 55mph. I had the guibo replaced on my E36 a couple of years ago, and it had kind of the same symptoms. It made noises while changing gears, and the car was shaking a lot. However, the E36 was shaking only at low speeds. The E34 is shaking only at "high" speed...


The front shaking is most like thrust arm bushings.
The whole car shakes. It feels like the steering wheel actually shakes less than the car itself. Maybe this leads back to the guibo as well?

I haven't had the chance to get under the car and check yet. I'm just hoping it can handle 250-300miles this weekend, cause I need to drive it home to my parents house to take a look at it there.

Also, another problem, at around 30-60mph (probably higher as well, haven't tried that yet) the front of the car feels a bit jelly. It kind of feels like it's slightly floating from side to side, and it feels like there's a bit steering play.


You can read about both these problems in more depth at www.bmwe34.net
Thanks for your help. I'll have a look...

[Jeff N.]

hmmm..the front end problem could be poorly balanced tires or bad tires as well. Might try a front/rear swap to help diagnose.

I'd try to:

- swap the tires front/rear and see if the shaking changes. If it doesn't, then it's mostly likely the front end thrust and control arm bushings. If the car hasn't had any front end work done, it might need a full job - tie rod ends, pitman arms, center link, bushings and adjust the steering box.

- carefully inspect the driveline. You'll be able to see the guibo without removing the exhaust. You can also check the halfshaft CV joints without removing anything; unlikely they are bad but simple to look. To check the center bearing, you'll need to drop the exhaust and heat shield. Since this is 1/2 to fixing any driveline problem, you may want to have the parts on hand. The safest bet would be a rebuilt driveline.

This is pretty typical stuff for a 100k mile car that hasn't had anything done in these areas. Will drive *much* better with these two fixes.

Jeff

[632 Regal]

Gotta trust a guy with the neme of Jeff, Sounds like you need to do a complete inspection on the car. You have a few things in need of attention, the front end thrust arms lead the most towards the 55mph shimmy, if they didnt torque them down at ride height that will cause them to fail early. Check all the rubber mounts from the engine/trans to the rear end bushings and the guibos. Also bad shocks will cause the dreded shimmy. The clunk is probably the eng/trans/rear end mounts and possibly Guibos.
Time to inspect and put together a nice size order!
thing is once this is all done you will be able to run on for a long time without any problems.
Good Luck!

[grr]

Thanks guys. I appreciate the help.

I just had the car 3 minutes over a "grease pit" (or whatever it's called, the hole in the floor kind of thing) and had a look at the guibo. As far as I can see it looks quite good. At least a lot better than the one we replaced on my E36.

Out of focus pic:

http://www.bmwguiden.no/albums/e34_520i/IMAG0054.sized.jpg

So, now I'm wondering what I should take a look at if I take the car over the grease pit again (without disassembling anything), just to see if it looks good enough to drive 250-300 miles this weekend, plus it would be nice knowing which parts to order already now. If anyone have any suggestions, please explain the semi-idiot way. I'm not very well versed when it comes to the mechanic part of cars...

Jeff mentioned the "halfshaft CV joints", but I have no clue as to what the CV joints are (I know what the halfshaft is). If anyone could tell me how they look like and where they're located I'll have a look.. ;-)

[Jeff N.]

CV joints are easy to inspect. You have 4 CV joints, one on each end of the half shaft. It's covered by a rubber-like boot. The boots should be intact. Lift the car such that one rear wheel is in the air, parking brake off, and turn the wheel back and forth. There will be a little but hopefully not a lot of play. If you hear the banging when turning the wheel, that's your issue. I'd be surprised if this was the problem but ...

Seems like a lot of oil around the back of your transmission. Did they check the fill level while it was up there?

[grr]

CV joints are easy to inspect. You have 4 CV joints, one on each end of the half shaft. It's covered by a rubber-like boot. The boots should be intact. Lift the car such that one rear wheel is in the air, parking brake off, and turn the wheel back and forth. There will be a little but hopefully not a lot of play. If you hear the banging when turning the wheel, that's your issue. I'd be surprised if this was the problem but ...
I'll have a look..


Seems like a lot of oil around the back of your transmission. Did they check the fill level while it was up there?
"They" was me. I was at a gas station were you can rent the grease pit per minute/hour (no tools, no mechanics), and had a quick look under the car. So I didn't check anything other than the engine oil level. However I noticed the oil, and I'm not too happy with it. It looked like the engine was leaking some oil as well. :(

Some more pics:

http://www.bmwguiden.no/albums/e34_520i/IMAG0039_001.sized.jpg

http://www.bmwguiden.no/albums/e34_520i/IMAG0040_001.sized.jpg

http://www.bmwguiden.no/albums/e34_520i/IMAG0046_001.sized.jpg

http://www.bmwguiden.no/albums/e34_520i/IMAG0047_001.sized.jpg

The plan is to check the transmission oil level and everything else some time next week, but I have to drive the car almost 300 miles on curvy and bumpy roads first. The banging, the vibration and the oil all kind of worries me. Crap.

This is the oldest and cheapest car I've bought so far. Maybe buying old "cheap" cars isn't that cheap after all... :(

[Paul in NZ]

the half shafts and cv joints are shown clearly in the top picture.The cv joints are at each end of each"axle".Make ure the diff mounting points to the chassis are intact.If the car hasnt been looked after the oil build up may look worse than it actually is

[grr]

Well, the car made it the 280 mile trip without any problems at all. I had the local Toyota (!) dealer look at the car for 15 minutes the day before the trip just to be sure the car would make it. They concluded the right subframe bushing was worn out and needed to be changed, but told me the drive shouldn't be a problem. So, now I've bought both the subframe bushings (err.. mounts..) and we're planning to look at it tomorrow (Printing the subframe bushing maintenance article as we speak;)).

I'm hoping the vibration and the sideways wandering at "high" speeds will disappear as well...

Thanks for all your help. I'll get back after we've changed them and let you know how it worked out. :)

[winfred]

it must be a euro thing, that looks like a e28 rear subframe and suspension, it doesn't have the big cradle like our e32/34.
the shimmy is classic wornout thrust arm bushings (upper control arms) they may be part of the cause of the floating combined with wornout struts. id also check out the steering linkage, a bad center link and or idler arm bushing can cause some weirdness, one of the worst fealings can come from having one blown strut and one good one, you go over a dip or bridge transition and the car trys to bumpsteer into the guard rail or ditch


http://www.bmwguiden.no/albums/e34_520i/IMAG0039_001.sized.jpg

[winfred]

"Bangs from the rear end when clutching"

that happins to me when i eat too much bad mexican food, i need to clutch my rear end before it goes bang :D

[Karl]

When guibo went out on my old car (e12) I felt it more at highway speed, particularly under acceleration.

[Jeff N.]

Have fun with those sonuvabitches... :D

[grr]

Have fun with those sonuvabitches... :D
Oh yeah.

Everything went just fine untill it was time to remove the damn bushing. We didn't have the BMW tool to remove the bushings with, so we tried making our own, but the bolts and everything just didn't handle the pressure. Those bushings must be a really tight fit...

We'll have to figure something out tomorrow. This sucked. ;) Even if we'd get them out, we'd never be able to get the new ones in without that special tool...

And well, I think we're onto something, this is the right subframe bushing after pulling out the pin holding everything together:

http://www.bmwguiden.no/albums/grdiv/Bilde031.sized.jpg

As you might be able to see from this bad photo is that it wasn't still in one piece anymore, so I'm pretty sure that thing must've caused some problems... ;)

[winfred]

i press the old bushings out with the new ones in a hydrallic press, if not done right this way can dammage the new bushings but i've done a lot of these and have it down to a art, in and out both sides under 30 minutes, it's safer to press the old one out then press the new one in, you can not get the job done with a hammer, it takes a hydrallic press or a threaded rod and spacers

[grr]

You press the old one out with the new ones? This means you press the new ones in from the bottom? I thought the rim on the old ones would prevent them from being pushed up and out..?

We'll try to get a hold of a hydraulic press tomorrow... (it's 2 am here now). If not we'll have to put everything back together and take the car to a local workshop.

[winfred]

no rim on ours, it can go in from ether side, don't forget to line up the arrows

scratch that, i just noticed this was on subframe bushings and not thrust arm bushings, same general idea on instalation

[grr]

Are we talking about the same bushings? These are the ones I'm talking about:

http://www.bmwe34.net/e34main/maintenance/suspension/Data/SubBush13.jpg

(picture from http://www.bmwe34.net/e34main/maintenance/suspension/subframebushing.htm)

[Jeff N.]

You can cut out the subframe bushings with a saws-all or similar tool. Getting them in without the BMW press is much harder. I have heard of people putting a jack and some wood under the bushing and then lowering the car down so the bushing presses itself it. I have never see this done and don't know if it really works. I have heard of others taking the entire subframe out of the car and then pressing the bushings in with the frame out of the car. Again, never tried this. Best of course if you can get the BMW tool or make one like it. If you make one, make it strong - real strong - as it takes tremendous force to push the bushing in.

Be careful of the edge of the bushing as it can "mushroom" out if you press on the edge wrong. Also, be sure not to use soap or anything to help the bushing slide in. The BMW book says only to use water to help it slip in. If you use soap, the bushing will slide partially back out when you apply power to the car!

Good luck!

Jeff

PS - that's my car in the procedures on bmwe34.net

[632 Regal]

I looked at them in my car and didnt get the procedure, it looked easy but now I follow!!

[Crewblunts]

When we did the subframe bushings on my car we had the tool but still had a lot of trouble putting them in so we froze them for a while and then tried again. It went much easier. I hope that helps

-Phil V

[grr]

Alright. Problem fixed. :)

A friend of mine works as a mechanic, and he's got a car ramp at his mothers house. He borrowed the mobile hydraulic press from the workshop he works at, and we (he) changed the bushings today. Both sides combined was just about 1 hour. I can't believe the workshops I contacted told me between 2 and 3 hours. I paid my friend about $60, and still saved between $150 and $250 on this. I'm very happy with that deal. ;)

And ooh yeah, all the noises, floating and the heavy vibrations are now history. There's still a slight vibration at the steering wheel at certain speeds, but it feels like unbalanced wheels, so I'll have them rebalanced sometime soon.

Thanks for all your help guys!