Got rid of my front end shimmy!

[Podmore]

Hah! Licked it at last. After replacing thrust arms, lower control arms, tyres, getting wheel run-out checked, alignment and wheel balance done twice and still having problems with the dreaded 80 -100 km/h shimmy, I finally got around to replacing the tailshaft centre bearing to solve a different vibration problem. Found the gearbox mount on one side completely separated, and the other one just about to go out to lunch. BMA provided new ones and I fitted them today, took the car for a drive and VOILA! no front end shimmy either. I suspect the broken mount allowed the whole engine and trans assembly to oscillate gently, which transmitted through to the front end via the engine mounts. As one of our fellow enthusiasts said "the process of finding solutions to each of the problems we will experience with our E34s is an adventure of unparallelled satisfaction".:p

[txp135]

could you please provide more info because I think my car might need this done...Thanks

[JD525IA]

Hah! Licked it at last. After replacing thrust arms, lower control arms, tyres, getting wheel run-out checked, alignment and wheel balance done twice and still having problems with the dreaded 80 -100 km/h shimmy, I finally got around to replacing the tailshaft centre bearing to solve a different vibration problem. Found the gearbox mount on one side completely separated, and the other one just about to go out to lunch. BMA provided new ones and I fitted them today, took the car for a drive and VOILA! no front end shimmy either. I suspect the broken mount allowed the whole engine and trans assembly to oscillate gently, which transmitted through to the front end via the engine mounts. As one of our fellow enthusiasts said "the process of finding solutions to each of the problems we will experience with our E34s is an adventure of unparallelled satisfaction".:p


The one between the guibo and the rear diff? If so, you would normally feel a thumping sound from a dead start when accelerating.

Let me know.

JD

[Podmore]

To clarify - I had a vibration, particularly noticeable on take-off and at about 60 km/h on a trailing throttle, which I figured was either guibo (flex coupling) or tailshaft centre bearing. Ordered the parts through BMA and dropped the exhaust (breaking two manifold to pipe studs in the process - that's another story!), removed the heat shield and dropped the tailshaft. Sure enough, the centre bearing, which sits in a flexible rubber mounting, was just hanging in by a thread. In the process of removing the tailshaft, I had to remove the gearbox mounting plate to get access to the front universal joint (no guibo on my model - I have a spare now, anyone in Australia interested?). There are two rubber mounts which fit between the mounting plate and the gearbox extension housing. One of these was completely separated, and the other one was collapsed and close to disintegrating. This did two things: as both mounts were squashed about a half inch thinner than new ones, it allowed the tailshaft to sag and load the centre bearing. This caused the top of the bearing mount rubber to stretch and it had started to let go (old brittle rubber). The other thing that happened was the back of the gearbox was able to jump about because it wasn't properly restrained by the mounts. This caused the vibration on take-off and 60 km/h. I suspect it contributed to the front end shimmy because the whole gearbox and engine assembly was then able to oscillate about the one remaining gearbox mount, motion which was then transitted through the engine mounts to the front sub-frame, and through this to the steering. So having replaced both gearbox mounts and the tailshaft centre bearing, it's now so smooooooooooooooooth it's like driving a whole new car. Hope this helps other shimmy searchers! It ain't all about the wheels ......

[ILoveMPower]

So you're saying your 88 M30 car doesn't have a guibo? How come mine did..?
If it's not a guibo then what is the rubber piece you talk of?

[Rus]

So you're saying your 88 M30 car doesn't have a guibo? How come mine did..?
If it's not a guibo then what is the rubber piece you talk of?

My guess is the the OP has an automatic car. Those do not have the guibo coupling. Manual transmission cars are equipped with it though.

[Ferret]

Hmm, mines currently thumping on takeoff at the moment - and rattling at speed around the 50-80mph range... The thumpings quite scary when the turbo kicks in :o

Cant get it to a mechanic for another week though, as I live about 250 miles away from the guy I really trust now.

Handy timing that I'm visiting my parents next week.

Will report back when I've had it changed and see what happend. :)

[Podmore]

So you're saying your 88 M30 car doesn't have a guibo? How come mine did..?
If it's not a guibo then what is the rubber piece you talk of?
The guibo is the flexible coupler located at the gearbox output flange. My June 88 535 doesn't have one, don't ask me why, I have a conventional universal joint. The "rubber thing" is the flexible surrounding in which the tailshaft centre bearing sits - it allows some movement but essentially keeps the bearing central in the mounting frame.

[BigKriss]

If you car is an auto, then they never came with a guibo.


The guibo is the flexible coupler located at the gearbox output flange. My June 88 535 doesn't have one, don't ask me why, I have a conventional universal joint. The "rubber thing" is the flexible surrounding in which the tailshaft centre bearing sits - it allows some movement but essentially keeps the bearing central in the mounting frame.