Purging the U.J.s...

[Forkie]

So thought 'nice easy job today - grease up the prop U.J.'s. Mmmmmm. Auto prop so splined at the nose,bolted at the rear. The rear is the original - no play so left as is. The nose end had play so a mate of mine fitted a new GKN unit I had bought. This was all a while ago. Back to today - Try as I might but on the 'new' UJ I can only get grease purging from 2 of the joints ( the nearest 2 to the nipple). On the original UJ I cannot get ANY to purge. Am I looking at back tracking here and a strip down, or am I missing a trick....

[Clifford Pope]

I've noticed this on almost all U/Js, new or old.
The grease takes the path of least resistance, and there are bound to be differences in resistance between the four limbs. So grease pours out of one and barely oozes out of the others. I think all you can do is grease it on assembly and then not worry too much. Many don't have grease nipples anyway, and they seem to last well.

That is assuming that it was assembled correctly. There are usually thin plastic shims at each end, which partly mask the holes in the ends of the limbs. If one had been left off then obviously that would become the easiest path.

[Phil T]

What Clifford said, plus the important issue is whether the UJ is worn or not. If they are not worn then don't worry.

They should last years.

[Forkie]

Mmmmm. Thanks for the replies guys. I do prefer to do things myself where possible - at least then you know HOW it has been done. I entrusted a good friend of mine to replace the nose end spider a while ago as I had to dissemble my bench with vice in order to site the car in the garage for the work ahead. He is normally quite methodical so I assume he did what was required at the time. So in your opinion - do I refit prop as it is , with only 2 purging at the nose ,and none purging at the rear - or do I start again. I am thinking I need to start again

[tony]

Don't forget there are seals in there to keep the grease in. I wouldn't be too worried not to see much.
Tony.

[Mike Stevens]

I'd leave it and see how it is when the car is back on the road. After all, it's a relatively easy fix!

There are 2 failure modes in a UJ (that I know of).

• It goes loose

• It goes tight!

The former is relatively easy to detect but you can't check for the latter without removing the prop. In my experience, the latter is more likely to give problems than the former.

Having removed the prop, each joint should be checked for stiffness over all it's range and on each direction. A stiff joint can put forces into the system when driving that come out as vibration. In the worst case (and I have had them in the past!), a roller or 2 'sticks' and you end up with ridges on the spider bearing surface.

Cheers,
Mike.

[Forkie]

Ok.Thanks for the replies. I have since purchased a new grease gun and flexi hose to suit ( up to now been using father in laws unit) which has seen some action.So if have a feel of each end so to speak, and post up, may that help me....?

[Clifford Pope]

.So if have a feel of each end

As Mike says, you need more than just a feel to detect a partially seized joint - you need to unbolt it and test for movement in all directions.

[Forkie]

The prop is off the car- has been for 10 years. I think I will take the advice of '' see how it goes' when back on the road.