Front propshaft - which way round?

that page is a from a LR disco workshop manwell SJR900 ENWM dated 1991, so maybe they changed it?

Maby it was because the 90s prop is shorter than the discos thus creating a steeper operating angle on the 90 so having the offset helps reduce wear and vibrations. (please note this is only an assumption)

D.G.F.S. said:

Maby it was because the 90s prop is shorter than the discos thus creating a steeper operating angle on the 90 so having the offset helps reduce wear and vibrations. (please note this is only an assumption)

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Sounds feasible to me.

Shifty1962 said:

Where do you get 90 degrees from?
RAVE diagram looks about 45 degrees offset on front prop.
They dont give an actual figure. Thats why I posted the diagram in my previous post.
Both of my props have this offset and they've done nearly 120,00 miles. I changed the original UJs at 116,000 miles because one of the spiders had a small amount of play The other three were perfect but I changed them and kept them for emergency spares if needed.

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from workin on farms, doin bits of plant work, building me own 90's 110's and series motors they have always gone on that way trouble free, nearly all that i have removed have been either straight or at 90 degs to each other, yes i have seen them at a 45 deg,
speakin to me neighbour thats a mehanic fer nato, rebuilding landrovers, recons the same, 90 or straight, spose its up to yer self , what ever yer think is right ! just i have seen them rattle like **** at funny angles :doh:

90truckcab said:

from workin on farms, doin bits of plant work, building me own 90's 110's and series motors they have always gone on that way trouble free, nearly all that i have removed have been either straight or at 90 degs to each other, yes i have seen them at a 45 deg,
speakin to me neighbour thats a mehanic fer nato, rebuilding landrovers, recons the same, 90 or straight, spose its up to yer self , what ever yer think is right ! just i have seen them rattle like **** at funny angles :doh:

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Wasn't criticising just asking if you'd seen it written down anywhere. I spent too long in the military and driving across most of Africa to worry about propshaft UJ offsets before now.

I guess each to their own and what works for you is the way to go. I'll stick to what RAVE recommends as it works for me. I dont trust Haynes for anything other than basic stuff. I've yet to have one of their manuals without mistakes or just plain incorrect info.

Shifty1962 said:

Wasn't criticising just asking if you'd seen it written down anywhere. I spent too long in the military and driving across most of Africa to worry about propshaft UJ offsets before now.

I guess each to their own and what works for you is the way to go. I'll stick to what RAVE recommends as it works for me. I dont trust Haynes for anything other than basic stuff. I've yet to have one of their manuals without mistakes or just plain incorrect info.

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ah kno mate yer wuint critisizin, i dont spose i really look at much paperwork , its all i have learned thru trial and error :doh:
but i think its the way to go, 90 or straight,

even speakin to the fitters etc, but if its in rave it cant all be wrong

D.G.F.S. said:

Maby it was because the 90s prop is shorter than the discos thus creating a steeper operating angle on the 90 so having the offset helps reduce wear and vibrations. (please note this is only an assumption)

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The 90 propshaft is the same length as the Disco 1 though.

In a nutshell - a UJ does not deliver constant velocity. It slows down and speeds up as it rotates. If the two UJs are in the same plane they automatically cancel out this speeding up and slowing down - producing constant velocity. This is true for the rear prop - the diff flange and handbrake drum are in the same plane relative to each other.

If the UJs are not in the same plan (like the front of Defenders, Disco 1s and RRCs for example) the prop will vibrate because they no longer naturally cancel each other out, e.g. a mismatch is created when the front UJ is accelerating the rear is wanting to slow down etc - eventually causing the UJs fail. By phasing the front prop by 45 degrees the effect is minimised, though never entirely eliminated.

A lifted car will often have UJ failures for this reason - the diff nose angle relative to the transfer box is changed causing irregular vibrations. Erroneously some folk fit wide angle props to reduce the failure rate, believing that the OE-sized UJs are under angular stress, when in fact they are suffering increased rotational variation. Hence castor correction kit not only makes the steering feel right - but more importantly restores the vehicle's prop angles and smooths the driveline out.

Quote
"hi, I read some of the thread but its hard work on a mobile phone!
why disco and defender are different I dunno!
on defender the prop goes with the sliding joint nearest the transfer box, the yokes of the uj's MUST be lined up otherwise it'll judder like fook. If you've ever studied a props characteristics..... The center part of the prop varies in speed compared to the ends so the steeper the angle, the more the speed varies. In one revolution the center section will change its speed twice. Believe it or not! Studied this in college. Stick this in the thread if ya want."

90truckcab said:

from workin on farms, doin bits of plant work, building me own 90's 110's and series motors they have always gone on that way trouble free, nearly all that i have removed have been either straight or at 90 degs to each other, yes i have seen them at a 45 deg,
speakin to me neighbour thats a mehanic fer nato, rebuilding landrovers, recons the same, 90 or straight, spose its up to yer self , what ever yer think is right ! just i have seen them rattle like **** at funny angles :doh:

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WELL.............

The reason The slipper end is on the transfer box end is in deed because it keeps the crap mud and stuff out of the sliding joint. It does not matter which way around but I prefer it at the transfer box end. Disco's are not Farm vehicles Defenders were built with that in mind.

OK The fromt Propshaft on all coil sprung vehicles are out of phase.
if they are in line they are WRONG, if they are at 90 degrees they are vVery WRONG simple. Series are different and are in line or inphase the front diff flange is almost 90 degrees to the ground. All coil sprung vehicles have the front diff pinion flange 22 degrees higher dont ask me why they just did it and has worked great for donkeys.

Phasing is done to counteract this and stop it binding or vibrating under full articulation or at speed respectivly. As for the mechanic that changed it to being inphase he is wrong and mabe he is a great car mechanic but he doesn't know his arse from his head when it comes to LR's and I wouldn't take my LR for him to work on. I would go back and change it.

Ok Phasing,

I think its one splines as per the drawing supplies so well by MHM. Make sure its phased correctly otherwise you will get premature failure and vibration/binding at atriculation. Note Rear propshafts should be Inphase.

P.s,
Disco's RR's and Defenders front propshafts are the same length if they use the same type transfer box. The rear changes as per wheelbase.

The Mad Hat Man said:

Quote
"hi, I read some of the thread but its hard work on a mobile phone!
why disco and defender are different I dunno!
on defender the prop goes with the sliding joint nearest the transfer box, the yokes of the uj's MUST be lined up otherwise it'll judder like fook. If you've ever studied a props characteristics..... The center part of the prop varies in speed compared to the ends so the steeper the angle, the more the speed varies. In one revolution the center section will change its speed twice. Believe it or not! Studied this in college. Stick this in the thread if ya want."

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Now I'm going to play devil's advocate here ....... :flame2:

I'm having some dificulty understanding how the centre part of a propshaft can turn at different speeds to the flanges given that they are connected via solid UJ spiders which as far as I know dont stretch or bend in any way.

I've been wrong on many occassions before and am happy to be corrected but I can find nothing on the web regarding this effect. :scratching_chin:

When the uj is dead straight the velocity is constant. As soon as it is at an angle it accelerates and decelerates - forget the web, take a prop off and try it. Can't explain why meself.

In the Landrover workshop manual for the rangerover classic it says the sliding joint go's on the transfer box end.It also says
"The front shaft which is shorter than the rear is phased with the joints each end miss-aligned,the phasing is necessary on the front shaft only to allow for greater variation in angular changes"

wot he said!

wreckhunter said:

In the Landrover workshop manual for the rangerover classic it says the sliding joint go's on the transfer box end.It also says
"The front shaft which is shorter than the rear is phased with the joints each end miss-aligned,the phasing is necessary on the front shaft only to allow for greater variation in angular changes"

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Same as RAVE says.