Diff and Gearbox mounts

[mauvstag38]

Hi All
I need to change the DIFF support bushes on my 71 mk2 can I use poly bushes or must I use rubber to match the rest of the suspension, also can I just jack up the diff to replace or do I need to drop the propshaft.
Same with the gearbox rear mount do I need to drop the prop shaft to change the mount.
By the way is there anyone in the Oxford area who can balance a propshaft.
Regards George.

[Charles H]

George
Chris Witor does the Superflex poly mounts for all of these applications. Either ring him on 01749 678152 or buy on line at http://www.chriswitor.com/
You do not need to drop the propshaft to replace any of these.

[Mike Stevens]

Hi George,

It was good to meet you at the weekend.

I've used the poly diff mounts with no problem. There are 2 each side, above and below the diff, so you will have to drop the diff a bit to get to the tops ones. You'll probably have to undo one side of the handbrake cable to do this. The bottom ones are easy, just support the diff first!

I don't know of a poly gearbox mount. I put a new one on the blue PI and that was a good quality one from Chris - in my experience, the cheaper ones last a few months. Again, support the gearbox and remove the mount - no need to remove the prop.

I hope you get the vibration sorted!

Cheers,
Mike.

[andyborris]

I would'nt worry too much about balancing the prop, I'm assuming that you've had to change the UJ's because the gearbox mount has "gone" and the extra gearbox movement has killed them.

Same thing happened to me, changed the mount and UJ's, which improved things greatly, but still left some very minor vibes.

Then fitted a new balanced prop and it made no difference, think the only way to get rid of all the vibes is to change all the rubber bits!

Andy

[Richard B]

By the way is there anyone in the Oxford area who can balance a propshaft.

I use Feltham Propshaft Services, West London.

Also check the state of the diff pins, they corrode and 'waste' away.

[andyborris]

And don't forget to use steel nuts to centre the alloy wheels (if fitted!)

Andy

[mauvstag38]

Hi Richard B Where will I find these diff pins to check, just changed bottom ball joints and arm bushes also steering rack ball mounts and reshimed , still getting vibration under drivers seat between 42 and 60 do not know where to look next. Any ideas are welcome.
I have steel wheels with new tyres.
George.

[TedTaylor]

This sounds suspicously like a propshaft UJ. You don't seem to have indicated whether you have checked or changed them.

Get the prop shaft off and check the UJs carefully for wear in all directions - you can do it from under the car without removal of you want but often it is better to get the prop off. If you do change the UJs, because of the length of the prop shaft it has been found that this can upset balance so you can either put the prop back without balancing and see what happens, or get it balanced anyway.

When removing the prop it can help balance if you mark the flanges (both prop and diff/gearbox) and the prop UJ yolks so that when they are assembled/replaced so that they go back in the same position.

Also check that the sliding joint moves in and out freely, has no play in the splines, and is well greased. If you take it apart mark the two halves to ensure correct re-alignment (there is no king spline to help you).

Ted

[CAR]

Get the prop shaft off and check the UJs carefully for wear in all directions - you can do it Also check that the sliding joint moves in and out freely, has no play in the splines, and is well greased. If you take it apart mark the two halves to ensure correct re-alignment (there is no king spline to help you).

Ted

To elaborate on the last piece of Ted's advice, the yokes of the propshaft should be in line front to back so that the flanges at each end would both drop down or both swing to the side at the same moment. (this is hard to describe Ted ).My old prop on the estate had a vibration even after replacing both UJs, then I realised the yokes were around 30 degrees out to each other. So you simply undo the sliding joint retaining ring and seperate it, reinsert in the correct orientation and tighten the retaining ring. You only need to undo the one set of propshaft bolts. This sorted the vibe for me.
Usually a tired gearbox mount will ruin the UJ at that end of the propshaft!

Colin.

[Mike Stevens]

To add to Ted's excellent suggestions, the UJs can also go tight. In my experience this can create more vibration than if they are loose. Looseness you can detect with the prop on the car, a tight UJ, you can't, so removal is the only option.

Checking that the ends are in the correct orientation is important and if wrong will cause vibration.

Cheers,
Mike.