Propshaft Poly Bush Fitting

(to cure propshaft ringing at low speed/low revs clutch take up combination.)

Aidan Talbot:
September 2005

This is the new replacement Poly bush as supplied by Gordon Craig in South Africa.

Note the flanged end on the left needs slightly profiling in order to fit the space vacated by the O ring – I lightly sanded the edges off to give a better profile and facilitate fitting.

I found I needed to hold the whole donut in a vice in order to undo the four Allen headed bolts holding the UJ and donut to the propshaft.

Once the bolts are undone and removed recover the four washers from between the donut and the propshaft and gently withdraw the whole assembly to leave you looking at the o ring and the two bronze bushes inside the prop.

This is the UJ, donut and shaft assembly that you have withdrawn from the prop.

This is the UJ, donut and shaft assembly that you have withdrawn from the prop.

I marked the prop and the UJ with paint marks before disassembly so I could put it all back together in the same orientation.

I didn’t remove the donut from the UJ as no need – it only meant that I couldn’t take a close look at the wear marks on the shaft bearing surface at it’s outer end. But I could feel the play when the bolts were undone before withdrawing the shaft from the prop.

4syncro-prop-bush

5syncro-prop-bush

Close inspection shows the wear on the bronze bush – there’s a swarf edge on the lower edge and the top edge has taken the shape of the o ring , being removed below

So you can see clearly the extent of the top bush which is to be removed. I cleaned out most of the old grease then stuffed a clean tissue into the tube below the bush to catch the waste that will be created.

Using an old chisel I cut two parallel score marks down the inside of the bush about 10 mm apart.

Using an old chisel I cut two parallel score marks down the inside of the bush about 10 mm apart.

Then carefully tapped a small bradawl between the bush and the shaft between the scored marks and broke out this section of the bush in stages.

Then carefully tapped a small bradawl between the bush and the shaft between the scored marks and broke out this section of the bush in stages.

Once the section was removed the remains of the bush were easily removed, a very little light filing required to remove the slight burr caused by the back of the bradawl. Turning the prop upside down and pulling out the tissue removed most of the waste, a blast from the airline and more careful cleaning ensured that the remaining lower bearing was free from debris and ready for some clean moly grease.

The remains of the old bush and the new one – I checked to see that it fitted over the shaft ok before I removed the old one..hence the spots of grease on it