Yet another E39 wheel/driveline vibration

[DHoang]

RR subframe bushings are not that common failure points on the Sedan....only on the Touring. My suspicion is, w/ the Touring's rr shock being repositioned more horizontal than vertical, the subframe bushings absorbs more of the load bearing down on them. This is a hunch, as I don't have the facts to back it up.

[champaign777]

RR subframe bushings are not a common replacement on sedan
They usually fail when you use bad drive shaft for some time

There is no way to check them on the car

[brc5]

Interesting.
You initially said the Rear Subframe Bushings appeared fine.
Yet replacing them helped.
I ask because I am considering replacing mine in the sedan.

What I originally said was 'there was som play in the rear subframe bushings, but they don't look visibly worn'.

Where I was wearing the fail-cap was not to remove the end cover plate off a subframe bushing and inspect it.

Had I done that while it was on the hoist (a 2 minute job) here's what I would have found:



Thos big cracks are a bushing failure. It is fluid filled, and the fluid leaks out and the bushing doesn't 'hold' anymore because there is too much play in it. I suspect the fluid has a damping effect as well. The front ones are always worse than the rears. The symptoms are vibrations, crashy rear suspension and vague handling, especially on first entering medium/high speed turns, as the weight of the vehicle shifts excessively.

Everyone has a theory as to why the touring bushings fail despite being physically larger. The fact that the front ones fail first seems to me to indicate that it's something to do with torque loads twisting the subframe, or perhaps the centre of gravity of it is towards the front.

As for the sedan, it's commonly regarded that the bushings don't fail, but the easiest thing to do is to jack it up, remove one of the end caps and take a look. If it's got big cracks in it, then by all means replace it. You'll need the special tool or a whole lot of luck and perserverance.

For the poster who said their wheel started wobbling after a track day, the most obvious conclusion is that you threw a wheel weight at the track day. That's not unheard of. You may have also damaged your tyre, although that is less likely.

This all reminds me, I need to list my touring subframe tool on ebay!

[champaign777]

this is a "disaster",the final stage of cancer and not a failed SF bushing

this is how worn Salon bushings look
"take a look" do not work here , when you have them new you can feel the difference

[jstern]

I know that this will sound strange but my wife's Touring had a very annoying shimmy in the rear at 65 to 70 mph. After alignment, balancing, etc. (all of which you guys have mentioned) it turned out to be the e-brake. The shoes had initially been dragging causing the vibration. Of course, they then got hot and started to delaminate. They broke up and caused more vibration. I found out what was going on by feeling the rear wheels after some highway mileage-they were quite warm.

Replacing the shoes and adjusting the e-brake properly fixed the vibration/shimmy.

You can check the condition of the subframe bushings by putting the rear of the car on jack stands, putting a jack under the diff to support but not lift the subframe and removing one of the bushings bolts. When the bolt comes out so will the metal plate covering the bottom of the bushing. If the bushing has cracks in it it is shot-the fluid has come out through the cracks and the bushing is acting like a brick, not like a bushing.

brc5-I did not see your post and pic before I posted-your pic is exactly what I mean.

[brc5]

this is a "disaster",the final stage of cancer and not a failed SF bushing

this is how worn Salon bushings look
"take a look" do not work here , when you have them new you can feel the difference

Is that the bottom or the top of the sedan bushings? I take it there were no cracks?

You're right about the final stages of cancer with the old bushings. You could feel the weight difference between the old and new ones, which accounts for the lost fluid.

[sciroccoboy16v]

I recently purchased a 00 528iT which had a terrible vibration that started at around 60 and continued above that. I had all wheels road forced and balanced at Canaga Tire Factory in Lebanon. One seperated tire which we moved to the front. I gained a vibration in the steering wheel from the seperated tire but noticed no difference in the major vibration. I noticed that when I went over a bump the rear suspension made a clunking sound and there was a shimmy. I ordered a set of the Meyle HD rear subframe bushings from EAC and replaced them tonight. (Also rented the Franklin bushing tool. Took an hour and ten minutes to replace all four.) Took it for a test drive and the clunking/shimmy was gone as well as the high speed vibration. Now time to order a set of rear camber kits and get rid of the tire wear issues in the rear.
Chris

[rswapp]

Having basically the identical problem, vibration at 20 but clears above.
Hoisted our car checked the Guibo, support center bearing and rear cv all appear to be good no play or cracks.
Half shafts appear to be fine, no problems there.
Found that the upper rear wishbone ball joint's on both right and left side races cracked causing quite a bit of support bearing movement.
The lower ball joints had been changed about 3 months earlier after doing a rear brake job and found excessive play.

Ordered the parts from Pelican, easy install and cleared up the problem.

Our problem occurred after my son crossed a set of RR tracks at low speed and hit two nasty holes that I think did the joints in.
They were probably already worn but the holes in the track crossing finished them off.
Did also find that his 245/40/18's on the rear really exaggerate the problem, I believe there is just too much added load for the rear suspension to compensate for.
If this keeps up we'll switch to 235's on 17" wheels.
Yes the our problem cleared up with the replacement of the two wishbone changes.

So I bought myself an E39 touring, and driving it home I found out it has a nasty vibration above 65mph. I did test drive it and look for this specifically, but where it was located there were no smooth roads, so I didn't feel it until I was on a bit of smooth freeway heading home.

The problem is a pronounced vibration in the car which appears briefly at about 30mph and disappears, only to reappear above 60. It's not through the steering wheel - it's definitely through the seat and you can see the passenger seat and sunvisors shaking.

After beating myself up about making such a schoolboy purchasing error for a couple of days, I started problem solving. Here's what I have done:
- wheel balance : no effect
- another wheel balance : no effect
- removed wheels off my other E39 and swapped over : no effect (other car has no vibration problem)

At this point I took it to the mechanic I use, who showed me the discs were all worn below the minimum spec. I had to get this fixed for registration purposes, so he fitted all new discs and pads around. While the car was on the hoist, we took the wheels off and ran the car up to full speed. Smooth as a rock, no vibration seen or felt through the car.

Re-fitted the wheels (still the ones off my other car) and ran it up to speed (still on hoist). Both left and right wheels visibly jumping the suspension up and down. Checked runout of rims - rims seem OK. Checked runout of tyres - a little bit of variation but not much.

Swapped other set of wheels to rear, and ran car up to speed on hoist. No jumping on right hand side, but wheel jumping a little on left hand side.

Mechanic concludes it must be wheels/tyres. I explain to him that my other car felt no such thing with those wheels - but the evidence was right there for me to see - no wheels - smooth. Wheels on- vibration.

While up on the hoist, checked all suspensions bushings and joints. Thrust arm bushings recently replaced (first thing he checked), slight wear in LHS transmission mount, but not serious. Guibo on driveshaft looks fine, didn't drop the exhaust to see uni joints - mainly because no noise and vibration is constant on road speed, and not on load (ie accelerating, coasting, vibration stays). There is some play in the rear subframe bushes, but they don't look visibly worn. I must say the wagon feels a lot more 'thrummy and drummy' than the sedan, I don't know if this is condition or just a wagon thing.

So at the moment the wheels are back on, and the vibration is still there, perhaps slightly less (it's hard to be objective about these things, as it depends on speed and road surface).

The original wheels are heavily kerb-damaged (every wheel) so his suggestion is to get the rims re-rolled, repaired, and put some new tyres on and see how this goes. He says this is the most likely reason and also the cheapest, because starting to replace driveline components is expensive.

The guy isn't an idiot and has been looking after a lot of E39's for a long time, so I'm inclined to believe him and try this route.

Any suggestions on what else to check, try? I know what a well sorted E39 is like, and it took a lot of convincing to the significant other to ditch her VW and get another BMW, so it hasn't gone over well. I'm very keen to get this one running smooth. It's a good car in every other respect.

My only guess is that the suspension is a bit worn, so is hyper-sensitive to out-of-balance wheels as it can't damp out any vibration inherent, whereas my other car might be a bit fresher and thus can isolate wheel vibration more (it has more miles, but has had a gentler life by the looks)

[brc5]

So I have no idea why my subframe bushing photo is now a bunch of teens, but anyway

Esentially if you have a vibration in the back, look for wear and tear in the suspension mountings. It seems to be that the big back wheels on a touring, coupled with sophisticated suspension means that any looseness anywhere will no longer be able to control the wheel and you'll get vibrations. Common sense is to look for out-of-balance rotating mass, but in reality the wheel/tyre combination is always a tiny bit out of balance and lack of control of suspension mounting means that it can be transmitted through the entire vehicle.

Anyway it's three years since I posted this and the car is still smooth on the highway and the issue has never reappeared.

[scookm]

Thanks for everyone's input. I also have a small vibration in the rear & will make some visual checks of all of the rear suspension usual suspects.

[agentrnge]

I had those partying teens holding my subframe to my car. They were absolute garbage. 1 of 10 would not buy again. Wobbled like crazy.

[jhelgesen]

Bought a 7/01 touring recently. Horrible vibrations at 70-80 (not to mention the speedo and odometer errors). Running 17” staggered sport wheels, newish continental tires. Changed the subframe bushings. Not any better.

Tires test good. Tried other rims and tires. Still bad.

Rear arms next?