Help tracking down a vibration

Quote:

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Originally Posted by ozscott

OK...this is getting old quickly. Shaft came back and went in. I am not happy about the condition of it, but that is another story.
I think the only thing to so is get a new shaft and go from there.

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It's tuff finding vibrations and frustrating .....

Please recheck the condition of all engine mounts and that Gearbox mount.



Now for a check that may relate to finding your problem ....

I have the Ford BA. It has a 2 piece tailshaft. The center of the shaft has a Bearing that is mounted to the body. To change it, You have to remove the shaft from the Diff and Gearbox ... Unbolt the center bearing (Split the 2 piece shaft) .... Install bearing and refit Tailshaft.

The Ford BA has Doughnut joints at the gearbox and Diff ends .... I refitted the shaft and ended up with a vibration ... Now, there is a solution and check for this which is the following.




From the Ford repair Manual,

The tailshaft is bolted to the doughnut and must be centered, so that when you turn the shaft ... it is perfectly centered

TESTING .....
Mount a Dial gauge to the body of car ... and set the dial gauge 130mm back from end of tailshaft .... You have to turn the shaft and have the dial gauge set, so that it can measure that the shaft is centered to the Doughnut ... I think the max of tolerance of "out of round" (centered) is 0.5mm




Have a read of a Mallory repair manual for a BA Falcon ... Tail shaft section ... Might help understand Doughnuts ...... and might make my thoughts and suggestions a bit more clearer.

Cheers
Mike

Many thanks Mike. All suggestions welcome. The RAVE speaks of re-mounting the (single) donut at the diff end of the rear shaft (front of rear shaft has a uni) and its a straight bolt together of flanges on spigot and bush with no adjustment available. At the front of course the drive is double cardin and front uni joint.

Cheers

Quote:

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Originally Posted by ozscott

Many thanks Mike. All suggestions welcome.

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Next check on the list is to look at the Flange itself at the Gearbox and Diff ends ....

Put the car on stands / rotate the wheels and watch the flanges rotate .... See if they turn a perfect circle and are centred .... (not wobbly)

You can set up a piece of wire as a guide instead of a Dial gauge



The reason for my suggestion is that I have had the same problem as yours, Except it was on my RRC 90 .... Different setup to yours, I know .... But had the same issue ... and if I removed the front propshaft (Tailshaft) the vibration was gone.

I replaced the front output bearing on the transfer box and it went away for about 1 month ....

I replaced the front propshaft with a brand new (Hardi spicer) .... made it better, but not fixed.....

I spent ages ... measuring this / pulling down that / Inspecting all components of the Diff / Axles / Propshafts / Flanges .... and NEVER got to the bottom of it.


In the end ..... it sorta just disappeared over time. Go figure. ;)

Cheers
Mike

Heres my story,
Vibration ever so slightly noticeable at 95-105klm/hr (sometimes), then about 105-110km/hr just annoying enough to back off back to 105, at 115km/hr feels like it might now do some damage if I don't back off. been that way for 8 years including before and after tyres, lift, donut, regular tyre rotation and new engine mounts, and over all this time its never changed.

Had prop-shaft out and checked, all ok.

I have a slight 'clunk' from backlash I think in the rear diff and I've never changed the G/Box mounts so thats on the list.

One other check I haven't done is the Handbrake Drum check and re-balance, I think there is a LR alert to this in RAVE for a cause of vibration and to check for any eccentric rotation and re-align using a Dial Test Indicator and mallet.

Thanks gents...really weird thing is that tonight for 20mins of varied driving it all but went and then came back !!

Cheers