217354 bush for front stub axle

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Originally Posted by wrinklearthur

I think those bushes were originally for locating the Traka joints in the 80".
If fitted up nicely with U/J's they may save the spline for a bit longer in the driving flange.
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Arthur,

That might be the reason, but as you say, if the bush was fitted in a vehicle with a UJ it might save the splines.
The only thing then is you need to grind a bit off the end each of the four 'arms' to allow some float in the UJ otherwise something else will wear/fail. That's why I'm thinking the UJ became a common item between propshaft & driveshaft meaning the bush was best left out because you couldn't have float in a propshaft UJ.
If you think about the flexing when in 4WD on full lock under power it explains why the driveshaft nuts are often loose (despite being split-pinned) and the driveshaft has eaten it's way into the back of the drive member.



Colin

Had a look at the Tracta joint (because I'm not that familiar with it) and found that it gives exactly the 'float' I'm talking about needing with a UJ.

The site below has a brief explanation of CV joints and there is an interesting comment on the use of UJ's. 'Very strong, simple to make but they need complicated support bearings when used in drive axles'
constant-velocity joint : definition of constant-velocity joint and synonym of constant-velocity joint (English)

Tracta gave constant velocity so was it a 'backwards' move to change to UJ's ?

Anyway, my thinking is still that the bush was removed because it could potentially cause problems with propshaft UJ's.


Colin

Read my SIII workshop manual last night and it mentions the bushes and reaming them to the correct size.
So they went during 2A production but did they reappear on Series III ?


Colin

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Originally Posted by gromit

The Father-in-law was visting the other day and we were discussing the missing bush.
He thinks that the shaft being supported in 3 places (the drive flange, the 217354 bush and the roller bearing) would create problems unless there is some end float in the universal joint (sideways play once the cups are installed).
I'll have to check my parts manual to see if the driveshaft UJ was a different part number to the propshaft UJ, thinking about it one is sealed and one isn't so they will be different numbers.

A propshaft UJ has no endfloat, maybe changing to a common UJ meant that the bush wasn't needed (or could cause problems if fitted ?).

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Hi Colin

I think that when the outside drive axle is held tight against the drive flange, the axle end float should be and is done, inside the side gears of the diff.
I say that because if you look at the wear mark on a old or well used front drive axle, that mark is always longer than the spline in the side gear.

This dosn't apply to the 80" tracta joint as both the swivel pin 'C' ends of the drive axle need to be fixed inrespect to the tracta joint block for the joint to work
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Quote:

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Originally Posted by wrinklearthur

Hi Colin

I think that when the outside drive axle is held tight against the drive flange, the axle end float should be and is done, inside the side gears of the diff.
I say that because if you look at the wear mark on a old or well used front drive axle, that mark is always longer than the spline in the side gear.

This dosn't apply to the 80" tracta joint as both the swivel pin 'C' ends of the drive axle need to be fixed inrespect to the tracta joint block for the joint to work
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Arthur,

I probably confused you with my description.

I mean 'side-float' in the UJ rather than end float in the axle. Difficult to describe without using my hands and that probably won't help you unless we video conference....

If you imagine all the tolerances within the axle, bushes, UJ, swivel hub etc. etc. The inner part of the shaft is supported in the diff and the roller bearing, the outer end is clamped against the drive member and guided by the bush. Even with the wheels pointed straight ahead what are the odds that all 4 support points are in-line ? Pretty remote.
Now turn the wheels and things get more complicated. Is the centre you are turning on even the same as the turning centre of the UJ ?

When I ran through it with the father-in-law we had the drive shaft, stub axle and a workshop manual on the kitchen table (Tracy wasn't impressed, I only got away with it because it was her Dad). The FIL worked at PBR with R&D many years ago, they had a similar issue with a vehicle and the solution was to grind a bit off the ends of the UJ arms, problem solved.

Maybe removing the bush allowed the outer end of the shaft to move a bit (flogging out the drive member in the process).

The more I think about it the more I'm surprised it works.


Colin

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Originally Posted by gromit

The more I think about it the more I'm surprised it works.

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Hi Colin

A harmonious working relationship could be said of it.

Got to go, Mum's home.
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Quote:

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Originally Posted by gromit

Had a look at the Tracta joint (because I'm not that familiar with it) and found that it gives exactly the 'float' I'm talking about needing with a UJ.

The site below has a brief explanation of CV joints and there is an interesting comment on the use of UJ's. 'Very strong, simple to make but they need complicated support bearings when used in drive axles'
constant-velocity joint : definition of constant-velocity joint and synonym of constant-velocity joint (English)

Tracta gave constant velocity so was it a 'backwards' move to change to UJ's ?

Anyway, my thinking is still that the bush was removed because it could potentially cause problems with propshaft UJ's.


Colin

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A good reference, but has a few errors - for example, it claims early Citroens and Landrovers used universal joints, where in reality early Landrovers used Tracta joints (as did most original Jeeps) and all except the earliest Citroen Traction Avants. The Tracta joint was introduced in 1926 by Gregoire for his Tracta front wheel drive racing cars.

The dropping of the Tracta joints by Landrover was a backward step in the sense of less engineering "purity" but was a forward step in reducing manufacturing costs and decreasing maintenance costs. It coincided with the change from full time four wheel drive to part time four wheel drive, when it was realised that most Landrovers spent most of their time on roads.

John