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The propshaft on the Marlin is a (very) shortened Marina propshaft. I am pretty sure its just part of the rear section, including the sliding joint.
I have a couple of problems with the one I am using for my rebuild the strangest of which is the little cap which screws on and protects the spline of the sliding joint.

propshaft_2 by Robin Martin, on Flickr

The cap, front right of the picture, is too big! It doesn't screw onto the thread on the propshaft being at least a couple of mm larger. It was loose and rattling arround when I stripped the car but I thought it had just come undone. I don't understand how this could happen unless it has been bodged at some time. Suggestions anyone? Also, as you can see, the felt seal and retaining spring washer are a little past their useful life. Is it possible to get replacements or am I going to have to improvise?

The second, minor, issue is that the grease nipple is missing from the front UJ.

propshaft_1 by Robin Martin, on Flickr

Does anyone know what size it is? And is it still possible to get replacement UJs. Luckily mine are NOT the staked type which I believe a lot of Marinas used. I cant feel any play or harshness in the UJ but I thought I might replace it anyway.

Cheers, Robin

I can’t help with the screw cap, but can advise that your “felt washer” should actually be cork. It’s probably saturated in grease, mine was when I last rebuilt it. From memory the grease nipple is 1/4” unf. It’s worth checking with your nearest propshaft reconditioning company (Google/Yellow Pages), they are likely to have the washer and nipple and if they are old school and never throw anything away probably a good used screw cap that they could sell you. Warning - there is a similar Escort screw cap and sliding spline unit but it is bigger diameter.

Thanks Chris
Closer examination revealed that the seal is indeed cork. There's a seller on ebay now who makes them to order - you just specify the outer and inner diameters.

I looked closer at the cap and it looks original - just doesn't fit. I wondered if it had come unscrewed a long time ago and rattling arround has stretched it. I think I might just clean it up until it is squeaky clean and epoxy it in place. Well it might work....
Cheers

Looking at both my parts and workshop manual there is no grease nipple on the Marina shaft.

The workshop manual give you all the grease point for maintenance but nothing regarding the front UJ.

The parts manual lists part numbers for all the grease nipples but nothing for the front UJ.

Could it be that you have a bit of a hybrid?

The plot thickens??

Adrian

There are three U/Js on a standard Marina or Ital. The centre and rear U/Js do not have a grease nipple, however the front U/J although the same dimensions as the other two has a nipple. I suspect that in the process of building your car that the builder chose to include a grease nipple.

Yes - I think the flange welded to the (very) shortened rear section of the propshaft came from the front. Strange that the designers of the Marina chose to use two UJ's without grease nipples and one with. I guess there must have been a reason....

Grease nipples - it’s about torque load on the UJ. The front UJ drives directly off the gearbox, with “raw” torque/power. On the Marina, the front section of the propshaft has a “Cush-drive”, it’s made up of two tubes with about an 3/4” difference in diameter, when fitted concentrically the gap is filled with rubber. This cushions the shock force torque of the gearbox output turning the propshaft from a stationary start. The middle and rear UJs are behind the Cush-drive and are protected from this.

In consequence the front UJ is under greater stress and wear and so was given a grease nipple.

If you look at a Ford Sierra propshaft, they protect the drive by having a big rubber donut behind the leading UJ which does the same thing as the BL Cush-drive.

Thanks Chris. The Marina is obviously more sophisticated than I realised!

After much thinking I solved the problem of the propshaft cap being too big. I had a bit of an inspiration while playing about with my 2CV based Pembleton. The driveshaft sliding joint has almost identical dimensions to that of the Marina and is protected by a rubber gaitor. A quick order to ECAS (2CV specialist) and i was in possession of a new rubber gaitor. It fits the Marina propshaft sliding joint perfectly!
propshaft_solution by Robin Martin, on Flickr

Inspired fix - love it.

That's a good mod, like it.
I think when I was looking for the parts for the prop I search online for the original part numbers and the middle lock over washer (RTC 1336 I think) was found on some obscure website that did not relate to cars. I did not have the issue you had with the screw cap and managed to get a new cork washer from Brown and Gammons