Propshaft Vibration

[grober]

Recently I am experiencing a slight vibration in my E220 COUPE 1995. It doesnt go away when I shift into neutral at approx 50mph. So I am thinking wheel bearings or propshaft, maybe centre bearing or universal joint??? I have checked the wheel bearings and they seem ok. When I checked the propshaft visually and by twisting it by hand I found the following.
1.Flexible coupling and vibration damper at the front OK.
2.Flexible couping at differential OK , but a certain amount of backlash from the diff. I could always feel this backlash before and oil level was fine so maybe everything OK.
3.When I inspected the centre universal joint (UJ) and centre bearing and splined joint:- bearing + rubber mount seemed OK, the UJ seemed OK but there was very slight play at the splined joint. The 41mm clamp ring nut seemed to be tight, but access with the exhaust in place was difficult.

I dont know enough to judge if this is OK. It is a splined joint so maybe it is supposed to move slightly and have some play????? Or should it be rock solid I dont know. How does the clamp ring nut work exactly? does it tighten a splined hollow shaft socket round the spined end of the rear shaft or what?? its not all that clear from the manual I have, without taking the joint apart. Any comments suggestions welcome Thanks

 

[joe bloggs]

Is the vibration through the steering wheel or the whole car?, Tyres/wheels ok? no bulges/runout?

 

[Richard Moakes]

Mine vibrates through the whole car when under power above 65mph, if you back off the power, it goes away.

Four new Michelin Primacy tyres made NO difference, and yes they were very carefully balanced (twice, on different machines) with weights outside and in.

I too have backlash in the diff, the driveshaft seems fine, no visible issues with the flexible couplings.

The American manuals mention a part that can be attached to the diff mounts to reduce vibration, perhaps I will try that next?

Alternatively, I have learned to drive slower and respect the old lady for what she is.

Regards,

Richard

1989 W124 300E

 

[grober]

prop vibration

The vibration,which I have to emphasis is slight ,can be felt thro steering-wheel, pedals and floor of the car. Someone not used to the car would probably never notice it, but I do. One day it wasnt there, the next after a fast 110 mile trip on mixed roads, dual carriageway, A and B roads it was. wheels and tyres seem ok on close inspection maybe I lost a balance weight somewhere along the line? My money is on the transmission at the moment, but any suggestions I will check out.

 

[dieselman]

If it's felt through the steering at all it will be connected to the front wheels. My car is sensitive to picking stones up in the tyre tread, but more likley it is a tyre going out of round or a ballance weight problem.

 

[grober]

propshaft clamping nut

Thanks for the suggestions so far but I would still like some info about possible wear or play in that propshaft centre union and how that shaft clamping nut works. Anybody out there dismantled their propshaft? I think most older mercs 190s, 126 class have basically the same setup.Thanks again

 

[barrie_davis]

Graeme
The 41mm clamping nut acts like a compression fitting. The only way the spline can move in the front prop shaft is if the clamping nut comes loose. When disassembled you will see that the spline slips into the front prop shaft thru a 'nozzle' that has three longitudinal slots. These slots close when the clamping nit is tightened stopping any further movement of the spline in the nozzle. Hope that is clear. Can?t think why it should come loose though

 

[NormanB]

Grober

This may or may not be relevant - if it ain't nothing lost.

I had a similar vibration - very obvious to me - as very used to vehicle if a tadge paranoid. Anyways I noticed a change and vibration was 'roughly centre console and at prop shaft rotational speed.

I had it put up on the ramps - the mechanic was well impressed that I had pinned it down by ear to frequency and approx position - he went straight to it and there was a prop shaft coupling bolt missing - don't know where it went either!!

A new bolt was installed immediately (obviously) and Guess What - no vibration!

Hope it is so simple for you.

Regards
NormanB

 

[Barrie Woollard]

Hello all,

I have a 350 SLC 1972 model, had the same problem when I bought the car just before Christmas, the rear flexible coupling bolts, three on each side of the coupling were slightly loose but the cause of the vibration was that two adjacent bolts on one side of the coupling has their shanks worn down to approx. 6mm diameter, fitted new bolts all around and car runs like a R---s-R-y-e, just like it should. Hope this helps. :lol:

 

[grober]

propshaft probs

Thanks to all who took the trouble to reply and Barrie Davis for his explanation. Hope to have some ramp time next week to pursue problem further. Will keep you posted if and when I get to the bottom of the vibration. cheers.G

 

[grober]

Mystery Vibration

The Saga continues:- I got the front wheels balanced OK checked the wheel bearings on all 4 wheels End float on front BEARINGS seems OK I can just turn the 3 lug washer behind the locking nut with one finger. no roughness or noise . visually checked the rear suspension arm rubber bushes, seem OK. Still to check the tightness of that propshaft locking ring again. Someone made a comment about tyres going out of round :?: what exactly does this mean? I checked the tyres roughly by placing a tool box up against the tyre tread i.e. zero clearance and rotated the tyre. I did see a gap of 2-3mm at one part of the tyre cicumference on both front wheels :cry: , but put that down to where the car had been resting before jacking it up. What sort of deviation are we speaking about if a tyre is out of round? And can it be measured manually easily ,if at all.