I am trying to replace the UJ on my front half shafts, as one of them was very tired, so it made sense to replace them both.

However, try as I might, I cannot install replacements – I have b*******ed up 4 so far trying.

I am carefully following the process described on YouTube by Britannica Restoration. I understand each step, the importance of keeping the needles in place, and how each step ensures they stay securely. I am sure I don't have stray needles.

I get one pair of cups installed OK with their circlips.
On the other pair, again following the process, I get both cups installed OK.
I use the vice and an appropriate socket to push one cup in enough to fit its circlip. I am really careful to ensure I push it just enough and no more. Then I try and do the same to the last cup, and I cannot get the cup to move in enough to give the circlip room using the vice. In the end, I try using my press and BANG, it b*******s up the other cup.

It seems that the UJ is about ½ mm too long to give the room for the last circlip. I have made sure that everything is clean and lightly greased – especially the slot into which the circlips should go.

I cannot work out what I am doing wrong.

I did wonder if the half shaft had somehow distorted and was 1/2 - 1 mm too narrow, but the fact I have the same issue on both half shafts would indicate this is unlikely.

All I can think of is that the part is wrong, or I have ordered the wrong part, but it looks pretty standard.

I have ordered britpart no RTC3690. My catalog has part number GUJ1198, which I believe has been superseded by RTC3690. I could try ordering the OEM version just in case that is subtly difference size? I have seen GUJ102 listed on another site.

I also have some RTC3346GKN that i have bought to use on the prop shaft. Not sure how difference these are.

Any other suggestions?

Only fit GKN.


Did this job yesterday, aside from the new outer shafts being Britpart, and thus needing a few seconds on the grinder to make the yokes the right shape. No problems.

Thought there were 2 different sizes of UJs?
Sounds like you have the larger uj that’s what’s causing the cups to break.

Does Brittanic do it the same as manual, is the difference you are doing is fitting 3rd cup completely when as I read manual , get 3 and 4 cups started then press them both in together , by putting them in together allows for better alignment, are you getting some grease in there too. They are tricky little muggers and I got needles falling out on one occasion

you have the correct part numbers for the front half shaft ujs and the prop shafts, but I would agree with wildfalcon get a branded make

Did you know that 'BRITPART' is an anagram of 'WHY DO THESE BUGGERS NEVER FIT I'M GETTING REALLY TIRED OF THIS'.

I had a right struggle with the uj's on the 2a, the yokes can go out of shape.
Just buy a propshaft, cheap enough and I doubt you do enough miles to wear it out. That's what ,I did in the end, I hate fitting UJ's .
Oh and aftermarket UJ's never last very long.

There are some tips I follow.
Ensure you clean up the yokes internally with emery cloth and make sure the surfaces are free from burrs or rough edges. Check the yokes are straight and not deformed or twisted. Buy the best quality uj that you can afford. Clean out the circlip groove with a thin screwdriver. Lubricate both the yoke inner surface and the uj cup with plenty of grease. Try and press the cups in slowly, evenly and ensure the cups sit square. As you press the cups in, keep moving the uj to ensure it is not binding. If it does, back off the pressure.
This seems to work for me.

many thanks. I have ordered some GKN UJ, so will see if i have any better luck with them. I will be EVEN more careful.

My eldest did have trouble with the pins moving, and getting trapped in the cup, but once he sorted that, all was well. He used the vice and a socket to tighten, articulating the joint as he went.

I used a G clamp and some sockets and the garage floor last time I did the Ninety, worked OK. I think they might have been GKN ones.

You have the wrong size UJs, there are ones for size for prop shafts and one size for front half shafts. Half shafts are RTC3690.

Using RTC3690 he is