Steering wheel vibration

Hi there,

I'm currently looking at buying a 1988 635CSi however it has a few issues which I am not sure about. On accelerating when you reach about 60mph the steering wheel starts to judder as though the wheel balancing is out (but this was checked last week so it is that!) and remains up to 90mph - not been any faster! Then when braking there is another judder between 50-40mph. None before and none after. I have heard this can be the upper control arm bush. Upon inspection and giving it a wobble by hand it looks OK - no obvious rubber squeezing out. Can they be still be disfunctional even if they appear alright? The car did have a new cross member fitted last year so could this have put out the geometry of the front suspension?

Another point is a small amount of corrosion on the rear 4" of the sills both sides - does this often hide a horror story beneath, or could it simply need a good repair? The car generally seems in very good condition with a little work being required on the interior. The engine and gearbox are very sweet.

The final thing is in relation to a leak - I remember reading somewhere about leaks with reference to the glovebox. The owners manual appears to have some water damage and I remember the current owner mentioning a while ago about water in the passenger foot well. Is there a common place for them to leak in the front?

Any help or comment would be much appreciated.

Dave (potential 6-series owner!)

Did you get the back wheels balanced as well. Sometimes the rear can be the culprit.

Another less likely possibility is the hub assembly. This more of a front drive problem due to the extra mass of the drive shafts.

This can be checked using an on vehicle wheel balancer. This is a two part machine 1 a sensor that is put under the bottom ball joint and 2 a sit on box that spins the wheel up to speed and monitors its position. These balancers are more commonly found in truck tyre outlets.

AndyS wrote: ...Sixes are very heavy on front bushes. They were designed for 14" wheels & skinny (by todays standards) tyres. Later Sixes like your Highline had much wider rubber which knocks the hell out of all the joints & bushes. If they haven't been changed in the last 3 or 4 years (or 30 -40k miles) then they'll need doing. Top mounts could also be suspect...

You might want to replace the upper and lower control arms with the uprated versions now supplied by Meyle. These apparently have the same heavy-duty bushes installed which were used on the E32 750i/iL (which was one heavy car)....

AndyS wrote: .....There is no such thing as "surface rust" on a Six. They are all rusting, it's just a case of how bad it is. Rust on the rear of the sills is potentially worrying. Inside will be much worse & it's where the rear subframe member attaches. If it's bad here repairs will be expensive....

...and you might just want to have a look in the rear footwells under the carpet... If it's even mildly damp, I think you might have a slight problemas tecnicos.....

durg wrote: What is the spec of the cars hub? I can find out hub the diameter of the replacement wheels.

The E24's hub diameter is 72.4mm

The E39's hub is 74.1mm.

AndyS wrote: There is no such thing as "surface rust" on a Six. They are all rusting, it's just a case of how bad it is. Rust on the rear of the sills is potentially worrying. Inside will be much worse & it's where the rear subframe member attaches. If it's bad here repairs will be expensive.

Thats like saying there is not such thing as a scratch lol!

Ive checked my six over, and in most places i only have surface rust, i can explain andy if required, but im sure you can figure this out.

The e39 wheels is an interesting one, im picking up some today! Anywhere in the south west area i can pick up some spigot rings, rahter than ebay? wanted to get these on th this weekend really!

anybody interested in 6 trx wheels (240's), two excellent tread, one good, rest illegal.

I havnt figured that out yet. i have a wheel vibration, that has got significantly less since driving her. The car was parked near the sea and this was when my difficult to comprehend "surface rust" started (i have pics six months prior with no rust at all (on the body externally).

I am thinking it could be a whole number of normal things besides suspension. I'm not jumping to conclusions. Brakes are spongy, but pull up straight nothing more. Whats the correlation to the bodywork exactly?