Xjs in board brakes
#1
Xjs in board brakes
Hello,
Hope you all don't mind me posting here as not really got a jaguar xjs, just the running gear in a cobra replica.
Uses xjs in board brakes but after advice please.
Rear hub bearing setup in the haynes manual shows 2 thou to 6 thou clearance...
have read on lots of forums that they should be -2 to +2 thou.....is this for xjs hubs outboard type...?
also I have a powerlock 3.54 diff which is whining ?on when get to coast speed very light throttle, whether that's 30, 40,50 or 60mph but more prominent at 60mph. Does this sound common for these and I suppose it's a full strip down required? Fresh oil is in and no change but only whines when warmed up.
Many thanks even if you kick me out lol.
regards
gavcob
Hope you all don't mind me posting here as not really got a jaguar xjs, just the running gear in a cobra replica.
Uses xjs in board brakes but after advice please.
Rear hub bearing setup in the haynes manual shows 2 thou to 6 thou clearance...
have read on lots of forums that they should be -2 to +2 thou.....is this for xjs hubs outboard type...?
also I have a powerlock 3.54 diff which is whining ?on when get to coast speed very light throttle, whether that's 30, 40,50 or 60mph but more prominent at 60mph. Does this sound common for these and I suppose it's a full strip down required? Fresh oil is in and no change but only whines when warmed up.
Many thanks even if you kick me out lol.
regards
gavcob
#2
Hello,
Hope you all don't mind me posting here as not really got a jaguar xjs, just the running gear in a cobra replica.
Uses xjs in board brakes but after advice please.
Rear hub bearing setup in the haynes manual shows 2 thou to 6 thou clearance...
have read on lots of forums that they should be -2 to +2 thou.....is this for xjs hubs outboard type...?
also I have a powerlock 3.54 diff which is whining ?on when get to coast speed very light throttle, whether that's 30, 40,50 or 60mph but more prominent at 60mph. Does this sound common for these and I suppose it's a full strip down required? Fresh oil is in and no change but only whines when warmed up.
Many thanks even if you kick me out lol.
regards
gavcob
Hope you all don't mind me posting here as not really got a jaguar xjs, just the running gear in a cobra replica.
Uses xjs in board brakes but after advice please.
Rear hub bearing setup in the haynes manual shows 2 thou to 6 thou clearance...
have read on lots of forums that they should be -2 to +2 thou.....is this for xjs hubs outboard type...?
also I have a powerlock 3.54 diff which is whining ?on when get to coast speed very light throttle, whether that's 30, 40,50 or 60mph but more prominent at 60mph. Does this sound common for these and I suppose it's a full strip down required? Fresh oil is in and no change but only whines when warmed up.
Many thanks even if you kick me out lol.
regards
gavcob
The diff needs a rebuild.
The rear hub setup is quite demanding, be sure you 100% understand it. The thread link here may help, see post 5:
https://www.jaguarforums.com/forum/e...cement-244184/
The bronze shim needs to be anywhere between +2 thou endfloat or - 2 thou preload. If you are rebuilding the hubs, as long as you use Timken bearings (OEM) the shim already in there should be fine. New UJs are worth putting in if they are old; but only really good quality ones.
This is for an XJS, but the hub design is the same, and the steps identical.
https://www.jaguarforums.com/forum/x...ebuild-225834/
#3
#4
Try one more thing before you rebuild the diff. Jaguar calls for a positraction supplement to be added to the gear oil.
It’s not in the oil you buy, most parts places look at you with a blank stare. Go to the Chevy dealer and ask for the positraction supplement.
I would drain the gear lube in it and see if it has metal particles first if so that’s a very good warning the rebuild time is nigh. But if not too bad you might try fresh 90 wt with the supplement.
How is the rear ended mounted? Is it on the rubber mounts Jaguar uses? If solidly mounted you’re in trouble. The suspension only works if mounted on rubber.
Race cars that rigidly mount the rear end have to bring the trailing links into the inner pivot point in order for it to get the required compliance due to the conflict in the arcs.
If that sounds confusing please ask me to explain. Otherwise the rear end will be torn up. And you basically have a rigid rear end.
It’s not in the oil you buy, most parts places look at you with a blank stare. Go to the Chevy dealer and ask for the positraction supplement.
I would drain the gear lube in it and see if it has metal particles first if so that’s a very good warning the rebuild time is nigh. But if not too bad you might try fresh 90 wt with the supplement.
How is the rear ended mounted? Is it on the rubber mounts Jaguar uses? If solidly mounted you’re in trouble. The suspension only works if mounted on rubber.
Race cars that rigidly mount the rear end have to bring the trailing links into the inner pivot point in order for it to get the required compliance due to the conflict in the arcs.
If that sounds confusing please ask me to explain. Otherwise the rear end will be torn up. And you basically have a rigid rear end.
The following users liked this post:
Greg in France (07-23-2022)
#5
The following users liked this post:
Greg in France (07-23-2022)
#6
Castrol syntrax is the stuff, easily available in the UK:
https://www.amazon.fr/Castrol-SYNTRA.../dp/B004UBDGYW
#7
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FWIW my Jaguar ROMs show .001"-.003" end float as desired, and amounts exceeding .005" falling into "must be rectified" territory.
But these hubs seem to be quite forgiving. What seems (to me) to be excessive end float never seems to create a problem as far as driving characteristics go, nor create noise/bearing problems. Certainly there's a point of no return, so to speak, but it's quite a ways out there. Bearing failures, when they occur, are more likely due to lack of lubrication than anything else, IMO.
I think any of us would be happier with less end-float rather than more, and some insist that pre-load is actually the preferable set-up. I dunno. Maybe taking it just down to zero would allow everyone to sleep better ?
Cheers
DD
But these hubs seem to be quite forgiving. What seems (to me) to be excessive end float never seems to create a problem as far as driving characteristics go, nor create noise/bearing problems. Certainly there's a point of no return, so to speak, but it's quite a ways out there. Bearing failures, when they occur, are more likely due to lack of lubrication than anything else, IMO.
I think any of us would be happier with less end-float rather than more, and some insist that pre-load is actually the preferable set-up. I dunno. Maybe taking it just down to zero would allow everyone to sleep better ?
Cheers
DD
The following 3 users liked this post by Doug:
#11
Have you got a photo of the setup?
As to hub endfloat, I on reflection agree with Doug, I reckon +6 thou is a bit too much.
#12
I wish you good luck and I’d sure be gentle about acceleration. If you look at every used rear end you’ll find 3-4 worn out needle bearings. On each location.
There is a reason the rear end has drag links. Light weight XKE’s ( the race car version ) either had rubber mounts or the drag link came in at about a 45 degree angle to pivot at he inner pivot point.
Maybe you will enjoy the rear axle steering you around?
#13
#15
The following 2 users liked this post by Jagboi64:
FerrariGuy (12-10-2022),
Greg in France (07-29-2022)
#17
Yes, mine was making noise everywhere. Actually, all the bearings looked like that, and the cross shafts in the limited slip had broken, filling everything with metal. The only thing I reused was the ring and pinion, I replaced everything else including the case. Mine was pretty extreme example though, I've not seen another Jaguar differential that beaten up
#18
Ok thanks for reply.
regarding checking pinion preload as previously mentioned before complete overhaul, I remove prop shaft and check force required to move flange when in backlash correct? It's a last ditch attempt so nothing to lose. What inch pounds am I aiming for? Or is it to see if pinion nut has been previously marked and if so has it backed off?
regarding setup as a whole would a watts link setup on the LCA help as in here?
Regards
gav
regarding checking pinion preload as previously mentioned before complete overhaul, I remove prop shaft and check force required to move flange when in backlash correct? It's a last ditch attempt so nothing to lose. What inch pounds am I aiming for? Or is it to see if pinion nut has been previously marked and if so has it backed off?
regarding setup as a whole would a watts link setup on the LCA help as in here?
Regards
gav
#19
The normal way to check the pinion preload is with nothing else in mesh, so the crown gear and axles have to be removed. Then you are measuring the drag on the pinion bearings only, and you're aiming for around 20 inch-lbs.
A second way is to mark the nut relative to the flange, loosen it off and then tighten to specification. I forget what it is, but plenty. You will need the flange holding tool and a long breaker bar to be able to exert enough force to tighten the nut.You have to do this by hand, you can't use an impact wrench. It should come back to the previous mark, but also there is a crush sleeve in there for generating the preload, so if you overtorque you can't back off the nut. The diff needs to be stripped and the crush sleeve replaced.
Yes, undoubtedly a Watts linkage would help. On the jag, the radius arms are there to prevent rear wheel steering caused by the whole IRS assembly moving under torque. It's amazing how much compliance there is in the mounts, so a way to control that motion is necessary.
My guess is your pinion mesh and/or backlash is incorrect, and that is what's causing the whine. It's possible that it's out of mesh because of bearing wear and a set of new bearings will cure everything, or it needs to be rebuilt. It's possible to rebuild it at home, as you have the manual. You must follow the instructions exactly, and make sure everything is in specification. You'll also need to be able to measure accurately to 0.001", and a vernier caliper isn't accurate enough.
Pinion depth is the critical first setup, if that is wrong, you'll never be able to get backlash and side to side carrier clearance set correctly - you'll only be able to set one, and not the other. The shims also go behind the carrier bearings, so you need a special bearing puller and a press. Anything other than the right clamshell type puller will destroy the new bearings. Expect to have to press the carrier bearings on and remove them several times to get the shims correct.
A second way is to mark the nut relative to the flange, loosen it off and then tighten to specification. I forget what it is, but plenty. You will need the flange holding tool and a long breaker bar to be able to exert enough force to tighten the nut.You have to do this by hand, you can't use an impact wrench. It should come back to the previous mark, but also there is a crush sleeve in there for generating the preload, so if you overtorque you can't back off the nut. The diff needs to be stripped and the crush sleeve replaced.
Yes, undoubtedly a Watts linkage would help. On the jag, the radius arms are there to prevent rear wheel steering caused by the whole IRS assembly moving under torque. It's amazing how much compliance there is in the mounts, so a way to control that motion is necessary.
My guess is your pinion mesh and/or backlash is incorrect, and that is what's causing the whine. It's possible that it's out of mesh because of bearing wear and a set of new bearings will cure everything, or it needs to be rebuilt. It's possible to rebuild it at home, as you have the manual. You must follow the instructions exactly, and make sure everything is in specification. You'll also need to be able to measure accurately to 0.001", and a vernier caliper isn't accurate enough.
Pinion depth is the critical first setup, if that is wrong, you'll never be able to get backlash and side to side carrier clearance set correctly - you'll only be able to set one, and not the other. The shims also go behind the carrier bearings, so you need a special bearing puller and a press. Anything other than the right clamshell type puller will destroy the new bearings. Expect to have to press the carrier bearings on and remove them several times to get the shims correct.
Last edited by Jagboi64; 07-29-2022 at 06:18 PM.
The following users liked this post:
EcbJag (07-29-2022)
#20
A watts link is only suitable for live (ie solid) rear axles and its function is to prevent side to side movement of the entire axle. It would therefore have no function on your solidly mounted setup.
Last edited by Greg in France; 07-30-2022 at 03:52 AM.