front UJ

[davidlandy]

Changed yet another UJ on the front prop today

thats the third one in 9 months! all on the diff end of the front prop.

I have been fitting the pukka GKN boxed item but still cant work out why they keep on failing.

any ideas?

[turtle]

I have the same issuess on standard props.

Have you lifted yours Dave? is so this would be the cause.

[davidlandy]

it is lifted by 2"

but this problem has been occurring since before then

getting bored with changed UJs now, can do em in my sleep!

[Budgie]

I had a propshaft where the U/J kept going and it turned out to be a slightly oversized I/D on the propshaft flange, where you push the U/J into. This wasn't holding the U/J bearing securely and causing it to move a ware quicker. I only noticed it on the second U/J I fitted cos it didn't take so much effort to push the bearing home.

The only other thing I can think of is an out of balance propshaft but you would feel that through the steering.  :?

[DIL]

I work on farm machinary which is often run by a PTO shaft with UJ's and it is common practice that you always set the Ujs in-line with each other, (when you slide the two parts of the shaft together you make sure both inner yokes are in line) this makes them run smoother at angles.

When i bought my Defender it had a knackered front prop, so i bought a new one which came with the UJ's at 45* to each other the same as the origional one. I set the UJ's in line and have had no problems since.

Dont know if this is any help but might be worth a look as your prop will be running at more of an angle due to the lift.

Cheers,

[davidlandy]

on the front prop the angles are at 45deg so as to stop binding unlike the rear prop that is set in line

if u try to put it back in line the splines on the prop are a very very tight fit.

I think that I have found acontributor to the problem - my front diff is knocking ! and has a lot of backlash, I suspect that its gotta a problem inside so I am on the look out for another, anyone got a 24 spliner laying about?

[Range Rover Blues]

I can't find anybody who can give me a sensible explanation as to why LR fitted the UJs out of 'phase' with each other, but they did.  I'd always recomend lining them up, I know what you mean about the splines getting very stiff though, there isn't supposed to be a master spline but I think it's the Shellack coating that normally runs in the void (breather spline) that hasn't worn away,  if you get it ouot of place the splines seem to lock up completely.

Anyway, that doesn't help you does it?   I don't think the lift is the problem, not on the front, the UJ angle doesn't change and if you fit QT arms then it actaullu does less work.  That said there is the 'pulsing' that we talk about regualrly but I'd expect that to trash the top UJ which is doing all the bending.

Vibrations form the diff, hmmmmmm, could be, if it's throwing the prop out of balance.

Going back to what Budgie said, try fitting the bearing cups with a little 'stud n bearing fit' to keep them still in the yolks, just in case.

BTW, when you say they are failing, what exactly is failing? is it the needles that are collapsing or the races on the spider? Is it the thrust washers on the ends of the spider's arms?

I'm going to assume you grease regulalry

[davidlandy]

the failure was that one bearing cup split around the circumference near the top - the needles inside were all mashed up together but i cannot say whether this happened before or after the cup cracking.

I still have the bits so I might take some piccys so we can all play a game of Quincy!

[Range Rover Blues]

PLease do, there shouldn't be space for the needles to move about at all so perhaps the outer race is flexing in the yolk causing it to crack.

Hey I know what, try fitting a s**te un-branded part from a dodgy motor-factor's, might make all the difference :?

[Range Rover Blues]

Does it always break in the same yolk?  try marking it with paint to see.  If it's the yolk on the flange you could swap the flange for a spare one.

[DIL]

Any luck finding the problem yet m8?

on the front prop the angles are at 45deg so as to stop binding unlike the rear prop that is set in line

Wot is meant by the term 'Binding' on the front prop? :?

[Mace]

OK guys, I checked my front prop out of curiosity to discover my yolks are set at around 30 degrees. Not right either way !!!

Question, does the prop just pull apart and slot back in again if I want to rotate the yolks or are they held together with circlips and the like ?

Thought I might try a little experimentation :-)

[davidlandy]

I say its 45 degrees because it looks like that ! , so best that we somehow check this.

having said that , if its not shakin and vibrating then I would leave it as is.

for info the prop does just pull apart theres nothing holding it together.

[Mace]

Dave, I just want to make sure because I've always had what I thought was prop vibration, especially since I put the 1" lift on it. I've changed all U/J's to be sure but it's still there, especially around the 30mph mark which can be frustrating at times. The front prop has a balance weight on it and I've got a small amount of play on the front diff flange. I'd just put it down to the small increase in angle since the lift.

I'd be interested to know what the prop yolks should be set at. 45 degrees or just not in-line. It will be interesting to find out if changing my yolk angles makes a difference.

[davidlandy]

i shall look at the manual when i get home

[Mace]

Found this in my *old* workshop manual

NOTE: Before dismantling the propeller shaft joint,
mark the position of the spider pin lubricator relative to
the journal yoke ears to ensure that the grease nipple
boss is re-assembled in the correct running position to
reduce the possibility of imbalance.

NOTE. The Universal joints on the front propeller
shaft are, by design, not assembled in-line with one
another. Nevertheless, the alignment marks on the
sliding member and propeller shaft must coincide
when assembling.

Hmmm... doesn't give you much apart from re-assemble in exactly the the way you dismantle it.

[davidlandy]

the first note is news to me!  , but very logical!

you will find that the sliding joints are a tight fit if you try to put them in the wrong (or different) plane.  so much so that the joint may not slide.

[Ben]

Sounds like it's worth getting the prop re-balanced. 'tis always possible that the imbalance has always been there, but is accentuated by the lift.

Not sure where you'd get it done, but there are plenty of places about - check yellow pages, or google.

Might be cheaper than a new prop, and the answer to all your prayers!

Cheers

Ben

[Mace]

I'm running out of time before the Belgium-Nationals so it'll have to wait. I'm thinking of living with it for now and buying a double cardon front prop from devon4x4 instead. Especially as I know the lift will get bigger one day ;-)

[Budgie]

I've run into a similar problem with the rear prop.
Since I put the Rangie one on with the U/J's at each end I get a vibration from 50-65 mph, and that's with the spacer in there as well.

So, until I have time to sort it, the old doughnut propshaft will have to got back on for Belgium cos I know that will run ok.  :roll:
Another little job for today!!

[Range Rover Blues]

Before I got the Cardan prop I tried aligning the UJs in the front prop and it does make a difference, for the better.

Like I said I can't understand why they come from the factory out of phase and no-one can explain it to me either.

[Xtremeteam]

at work just recently we have started to fit a new style front prop to combat the uj failures comonly seen on farm & heavy abused,sorry used vehicles,the uj itself is a lot bigger than the standard setup & the complete prop is £5 dearer than the standard 1,can find out part nos if any1 is interested

[Range Rover Blues]

That would be a good idea.  How much of the LR prop can be retained, or are we looking at a complete new prop?

[muddyweb]

Does the larger UJ not accentuate the problem of the rotational velocity changes, and make the rumbling worse ?

[Xtremeteam]

its a complete new prop that fits straight on,will try n remember to take a note of the part No on mon as ive got to go n rewire my 90 this afternoon

[Wolfie]

Like I said I can't understand why they come from the factory out of phase and no-one can explain it to me either.

Have thought a bit about how to explain this, but without delving into a demonstation using 3d vector analysis, or having the x-thousand quid for a copy of ADAMS, it's a bit difficult to put into words.

If you have a look at Kinematics of Universal Joints and Complete compensation for uneven movement by the Second Joint you should be able to see why the joints need to be out of phase. I'll continue to think how to explain it and maybe come up with something sensible.

I can see why they need to be out of phase and why lifting would require a change of phase angle (even if camber compensated arms are used) - I'm just not very good at putting things into words.

Regards

Andy

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[Range Rover Blues]

Yeap, I know all that but it still doesn't explain why the 2 joints 'should' be out of phase, the gearbox output shaft and the diff pinion shaft are both in line with the chassis, so the deflection is only in one plane therefore the first joint and second joint should be in line with each other, effectively cancelling each other out.  Or is the diff pinion further to one side than the gearbox output?

[Wolfie]

Or is the diff pinion further to one side than the gearbox output?

Looking at the Haynes BOL it seemed that the propshaft is not parallel with the vehicle centreline, so I had to go and look at the car. On Heather (200Tdi defender) a (very) rough measurement shows that the diff pinion is about an inch and a half further outdoard than the tranfer box output flange.

It's all beginning to make more sense to me, I remember wondering why the joints were out of phase when I replaced my front prop but accepted it without researching the reason.

I feel a challenge coming on - a simple way of detemining how the prop should be set for different set ups, but this would be complicated by the need for accuate measurements and the variability of what a 2" lift does.

Regards

Andy

[Range Rover Blues]

Given that the prop is designed for a standard height car, then if the diff pinion and gearbox output are not in line, I can see why the UJs don't line up on the propshaft, because they are in fact 'in phase' with each other.  I'm going to go lie under the car for a while.......


However, for a 2"lift, yet another reason to go for a Cardan joint :D

[Budgie]

I'm going to go lie under the car for a while.......

I'd think you'ld need to after that little lot of thinking on a weekend!  :lol: