P38A Front prop vibration at 45kmph

Hi all,

I had to change one of the UJ's on the front prop of a 2.5DSE auto P38 (the one closer to the TC). After replacement, on test drive i noticed a vibration, mostly in the steering wheel, very fast but not violent at all. After this i climbed back under the car, and thinking I must've accidentaly lost the phase on the prop, i slid the splines out and reffited so that the UJ's are now in line. No difference, same vibration, not stronger, not weaker.

Vibration occurs between 40 and 50kmph, being strongest at 45ish. I have driven up to 120kmph, but I didnt notice anything out of the ordinary. Vibration is weaker in motorway height, stronger in normal height, and quite bad in wading height.

Here is what I have done so far:

- Replaced UJ that had play in it with a Bearmach one.

- Cleaned the inside of the yoke, yet new cups still went in very tight. I had to use a hammer as I dont have a vice.

- After replacement, I greased all the nipples

- The new UJ was a bit stiff, but i had this happen on other LRs and there was no vibration plus they are still going strong now.

- Thinking that I mustve somehow put the prop out if phase, I took the splines out and fitted them back in phase. I have now read that all p38s are supposed to have the ujs slightly out of phase. I can fit back to normal if this is an issue?


What is the most likely cause of this vibration out of the things i have listed? I have to rectify this asap.


Many thanks,
Matt

Original props are out of phase. Britpart in phase.

Are yokes free to move? Vibration from props usually felt through the seat rather than the steering wheel.

After you have fitted the new cups and clipped everything back together, tap around the uj head with a hammer it will realese any assembly tension.
Hopefully that's all you need to do.
The old phased or none phased question

I understand that the originals are not phased. Should i then refit the splines back out of phase? They are rather stiff i have to say! Yokes are free to move. No vibration in the seat. I can try to hammer the yoke on the weld however.

Just a few taps around the yoke assembly needed nothing major kiddo.
We've got 38' with a phased prop and a 38' without, it's a good question about phasing

So hammering it did not help, but luckily after driving it around for a while and especially on a very bumpy road, the vibration seems to be almost gone.

Are you sure you got the UJ centred between the cups ?

I don't see why it wouldn't be. The cups were flush with the circlips after the installation.

pwood999 said:

Are you sure you got the UJ centred between the cups ?

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