PDA

View Full Version : rear drivetrain setup



neil50
20-02-10, 07:03 PM
Time for some basic questions but i thought i better ask them before i put everything together and find i have to take it apart again. I am building an AK Gen II on XJ40 running gear.

I have fitted the new bearings into the rear hub using the shim that came off the original setup. Am i correct in saying that i have to tighten up the setup onto the splines (without the drive shaft connected to the yoke) to check the end float. if the end float is not correct i have to strip out the bearings again to change the shim?

Is it best to mount the diff to the chassis on its own prior to connecting the drive shafts then the hub assembly?

I have the original shims/spacers to connect the drive shaft to the diff, but am i correct again in saying that i may have to use new ones due to the shortening of the drive shafts.

I have read that i may have to use shims between the flange and the disc to get it to run true through the calliper, i cannot remember any coming off the donor setup, is this normal?

I thought about just getting it all refurbished and setup by someone else but decided that i want to do as my as i can myself. I'm not to bothered about things not going right the first time as the reason for building is for the "experience", however i don't want to put something together and then find out its wrong when i have built everything else around that assembly.

I am sure i will have many more questions to come in the future.
Unfortunately i am currently working 13 hour shifts which includes commuting 800 miles per week to and from work so i don't have much spare time to play in the garage. looks like I'll be keeping my sumo another year at least so i at least have a cobra on th road while I'm building the AK

thank you in anticipation of replies (or funny comments)

Purple AK
20-02-10, 07:27 PM
Hi Neil. That Sumo looks like it will come in handy then! I know nothing about the XJ40, but assuming it's basically the same as the XJ6 I'll answer as best I can till someone with better knowledge comes along.;)
Time for some basic questions but i thought i better ask them before i put everything together and find i have to take it apart again. I am building an AK Gen II on XJ40 running gear.

I have fitted the new bearings into the rear hub using the shim that came off the original setup. Am i correct in saying that i have to tighten up the setup onto the splines (without the drive shaft connected to the yoke) to check the end float. if the end float is not correct i have to strip out the bearings again to change the shim?
Yes but once you have measured the end float you just need to pull the spline back out and fit the correct spacer to give the correct end float. (no need to dismantle the bearings)

Is it best to mount the diff to the chassis on its own prior to connecting the drive shafts then the hub assembly?
Yes.

I have the original shims/spacers to connect the drive shaft to the diff, but am i correct again in saying that i may have to use new ones due to the shortening of the drive shafts.
Possible. The shims are used to set the camber. So you may have to adjust.

I have read that i may have to use shims between the flange and the disc to get it to run true through the calliper, i cannot remember any coming off the donor setup, is this normal?
AFAIK it is not necessary on the XK40 as the disc is mounted to the hub. Hence why there were none on it when you dis-assembled it.

I thought about just getting it all refurbished and setup by someone else but decided that i want to do as my as i can myself. I'm not to bothered about things not going right the first time as the reason for building is for the "experience", however i don't want to put something together and then find out its wrong when i have built everything else around that assembly.

I am sure i will have many more questions to come in the future.
Unfortunately i am currently working 13 hour shifts which includes commuting 800 miles per week to and from work so i don't have much spare time to play in the garage. looks like I'll be keeping my sumo another year at least so i at least have a cobra on th road while I'm building the AK

thank you in anticipation of replies (or funny comments)

neil50
20-02-10, 07:51 PM
Chris, thanks for the quick reply.

If the endfloat is out and i have to adjust it, where does the adjusting shim fit? The only shim i had was in the midle of the hub betwen the spacer and the bearings. Does the adjusting spacer fit betwen the yoke face and the outside of the bearing?

this is one subject that i am not totally understanding, the setup and geometry, caster, camber etc.

Purple AK
20-02-10, 09:28 PM
Chris, thanks for the quick reply.

If the endfloat is out and i have to adjust it, where does the adjusting shim fit? The only shim i had was in the midle of the hub betwen the spacer and the bearings. Does the adjusting spacer fit betwen the yoke face and the outside of the bearing?

this is one subject that i am not totally understanding, the setup and geometry, caster, camber etc.
Seems I was wrong in it being the same as the earlier models Neil :( If you go here
SNG Barratt - UK | Downloads | XJS Parts Catalogue (http://www.sngbarratt.com/catalogue/downloads/show.asp?id=16) Pages 29-31 it shows what is what (ok it's later XJS but they used the same setup. I guess you really need a Haynes Manual

neil50
20-02-10, 10:28 PM
Seems I was wrong in it being the same as the earlier models Neil :( If you go here
SNG Barrett - UK | Downloads | XJS Parts Catalogue (http://www.sngbarratt.com/catalogue/downloads/show.asp?id=16) Pages 29-31 it shows what is what (ok it's later XJS but they used the same setup. I guess you really need a Haynes Manual

looked at the pages and i have a spacer (no 78). this is the one in the middle of the bearings so if the end float is incorrect the bearings have to come out to put in a new spacer. what a balls ache. i have the feeling that i Will be buying loads of spacers as i am not lucky enough for it to be ok with the original spacer. what makes it even worse is that when i stripped it all down the grease and bearings etc looked quite new!
is there anybody else that is using XJ40 gear and has had problems setting the end float and had to keep striping the bearings out? this surely cant be god for the seals.

Stevednorris
21-02-10, 12:30 PM
Hi Neil, I've got to confess, the only things i didn't do on my rebuild was the calipers (bought recon ones) and sort out the rear hub bearings. I took them to a local independant Jag specialist. He sorted them out for me, for £50.