Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
21
Not the only concern, actually. Back in the day my wife had a RWD Toyota that developed an irritating squeak. Just about went nuts trying to figure out what was squeaking. Finally got the car up on a lift where I could spin the rear tires by hand, and when I did the entire transmission bounced up and down! It was the transmission mount that was squeaking. Come to find out the forward U-joint on the driveshaft had completely seized in one axis. Tested OK because it had no slop, but as the shaft rotated the U-joint wouldnât move so the whole transmission had to lift up. 90 degrees later was the still-moving axis of the U-joint, so the tranny would sit back down.
U-joints are cheap as dirt and cannot be lubed after installation. Yeah, I know, you can get them with zerk fittings for greasing, but that invariably lubes one of the four bearings â the one it blows the seal out of. The other three stay dry. Better to use non-zerk U-joints and assemble with quality grease. And if you dunno how long theyâve been in there on a 50+ year old car, probably a good idea to swap them out when itâs convenient â especially if you wish the car to be reliable for day trips and the like.
Good point Kirbert, Just may replace them, just because they are at least 35 yrs old (Since I owned the car, 70,000 miles, probably the original)
Update: I completely dismantled the IRS
very happy I did not encounter any seized bolts, fulcrum shafts etc.
only issues was one of the front Radius arm bushings as well as some of the safety wire broke off in the bolt hole (Darn happy)
The only wear and tear was the Radius Arm Bushings front n rear, the anti sway bar bushings and one of the hand brake pads was cracked. The Cage to Body rubber mounts are good, and I am not changing them for the world unless they are showing cracks etc, I donât want to fool with the new stuff unless i have to.
Its a well built unit.
Having a lot of fun doing it too. I think I enjoy working on this machine since 1982, as much as I enjoy driving her.
Really no special tools needed, (Craftsman Tools, LOL)
in addition to the present IRS project I had so much fun rebuilding and putting the engine together 4 years ago, that I am now preparing another engine with a little more power output in mind.
What a hobby
Regards everyone and have a great Holiday season
Finally in the homestretch, everything is coming together nicely,
Now itâs time to set the camber on the IRS
Going to do it while the unit is out of the car.
I have heard that was the way Jaguar did it in the factory. But who knows?
I plan on leveling the unit nice and plumb, then using all my leveling tools as well as level on my iPhone too to get that 1/2â negative camber
I also plan on measuring it at the hub threads. I will put some upward load on the hub to allow for any play in bearings.
Then after all this, do it again once the unit is in place
I hear that setting the links while the springs and shocks are in place can be difficult
Any opinions are greatly appreciated
HiâŚwith the IRS out of the car you will never get the setting links on with the springs/shocks connected⌠even with the irs on the car you will need a lot of weight on the rear end to compress the suspension enough to fit the linksâŚthen after doing this and setting camber then removeing links and standing back looking at the rear you will not have neg camberâŚit will be posâŚso you will need to adjust shims againâŚmy advice is forget the links and set to your req camber with the irs in the carâŚSteve
I set my camber upside down on the bench with setting links before the shocks were installed. I used the outer vertical surface of the hub, which is machined accurately for the measurement. Worked like a charm.
Hi BillâŚare those pieces of timber the setting links âŚthe service manual shows rear camber setting links connected to the IRS mount and the hub carrier shaftâŚSteve
If I remember correctly I scaled the drawing in the manual to determine the length between the shock centers. Itâs more important to have the camber the same side to side than the absolute value of it. There are numerous alignment threads, I suggest you read them before you decide on 1/2°
Note: there are spacers between the straight edge and the wheel rim to keep the edge clear of the tyre. The camber measured afterwards on the car was as I set it up on my âbenchâ setup. I used turnbuckles as setting links:
Hi DavidâŚi cannot see how you had the same camber measurement when the IRS was reinstalled as when it was on the benchâŚwhen the car is back on the ground and suspension settled it sits much higher with its springs and shocks than the height created by the turnbuckleâŚunless you put a huge amount of weight on the rear end far more than the usual weight of driver and full fuel tankâŚI have tried this several times and the car always end up with pos camberâŚSteve
MGC
I believe that the only important factor in setting the Camber is to achieve that dimension that is shown in the workshop manual that âChurchill tool #J.25â shows in that location. Which shows 8 3/16â center to center. How you get to that dimension ,and hold it, to take the camber measurement of -3/4â can be done many ways as per the creative ways shown above. Once u are at the 8 3/4â Mid laden point, thatâs where jaguar wants us to be at -3/4â point.
Then when u place the unit back in the car, the spring will compress to whatever it was in the first place and the camber will change as designed as the wishbone halfshaft assembly move up n down.
I just find it very interesting that the workshop manuals show only the âIRS in place on the carâ method. They also mention to drift out the bottom shaft to the shock absorber for the front shocks only? Why?
Lol, I am not going to over think this either.
Itâs easy if the irs unit is off the car and no springs/shocks . Otherwise u need to compress the springs as per the manual. Which as u point out difficult.
Regards
I can only report what I saw. I set the camber on the bench with the turnbuckles. I installed the IRS and then loaded the car to simulate driver/passenger and fuel load (bags of softener salt), and settled the suspension. I measured the camber and it remained in spec. Maybe my rear springs are less stiff than yours? You donât seem to mention loading up the car to simulate the weight of a driver, passenger and fuel before settling the suspension. That is essential, or you will, of course, end up with the rear end much higher than the setting link distance. Getting the rear to settle properly is far from easy either. I imagine that this is why Jaguar specified a setting link.
Hello Rocknjag,
The method described in the manual is with the car sitting on its wheels when fitting the setting link. By disconnecting one shock/spring assembly on each side, youâre only fighting half the resistance from the springs to compress the suspension. Both per side canât be disconnected as the rear end would collapse onto the bump stops.
Thanks Bill
Thatâs what I thought would be the reason too, but the way it is described in the workshop they first say to compress the back of the car to slip on the setting links, then disconnect the forward rear shocks. I am being picky, itâs great to have a forum nowadays to ask others. I am just happy that it is possible to set the camber while the irs unit is on the bench
Regards
Rocco
Hi RoccoâŚit will be easier to get in to add/remove shims if the front shock is removedâŚyou have more roomâŚi agree the way the process is described in the service manual is not very goodâŚtrying to remove the front shock would be very difficult with the links in place and the suspension compressedâŚyou will struggle anyway to compress the rear far enough to fit the linksâŚSteve
Curious as to why everyone is discussing resetting camber. When I rebuilt my rear, I simply kept track of where all the shims came from and reassembled in the same manner. Assuming camber was correct before, it should be correct after, shouldnât it. Mine did.
Larry
You are right
But I am replacing the 3:54 differential with a completely different rebuilt 3:07
Now I have been told to scan the old posts on Jag lovers regarding what degree to set to, lol
But as some have already stated, the most important aspect is to get both sides equal and close to spec as possible
Perfection is nice but unattainable,
Ty all
Rocco
Ps I am greatly enjoying this project, as it turned the rear brakes needed more attention than expected, all the rubber bushings and mounts too as expected
The universal joints were solid, at 75,000 miles as well as the bearings , but I swapped them out anyway
Just finished replacing the old 3:54 differential with a 3:07.
Rebuilt the IRS
Unbelievable, Very happy with the 3:07
Much better shifting points
The only trouble I encountered was bleeding the brakes
The problem was due to a swelled rubber hose line connecting the brake fluid reservoir to the master cylinder. Once changed to the proper rubber line, it was no problem bleeding the brakes
