Diff pinion - damn and blast

So I’ve made a boo boo and taken the nut off the Salisbury pinion without marking it.
I’m happy to fit a new crush sleeve but I don’t have a suitable dial torque indicator to accurately set the pre load.
Can I machine a non crushing sleeve to the exact same length?
Or where can I get a cheap low torque dial indicator - I don’t really fancy the fishing scales idea.
Or is there another option?
Cheers all.
Jim

There’s a couple of second hand dial torque wrenches on eBay.

123-eddy09 said:

There’s a couple of second hand dial torque wrenches on eBay.

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I was looking this morning. The torque is only 3nm at the top end and most of those available say 3nm to 40 or something. I was hoping to find a smaller one but I guess beggars can’t be choosers.

I've done them by hanging a weight off a horizontal piece of flat bar bolted to the flange. For 3Nm that would be 1kg at 300mm from the centre of the pinion. No calibration doubts when you do it like that.

boguing said:

I've done them by hanging a weight off a horizontal piece of flat bar bolted to the flange. For 3Nm that would be 1kg at 300mm from the centre of the pinion. No calibration doubts when you do it like that.

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+1. IMO better than a TQ wrench for a one off because of the lack of calibration issues - probably a PITA for repeat work ....

Well, I’m committed now I guess.

So tonight I started to reassemble the diff pinion and it’s not going well.
New crush sleeve, oil seal, oil thrower washer and seal gasket.
Cleaned everything up and put the pinion in.
As soon as the flange is down onto the oil seal the pinion is rubbing on something. I’ve not tightened it down on to the sleeve yet - just drawn the flange down to the bearings. what could be rubbing? It’s metallic but I’ve taken it apart several times and can’t see any fouling.
My head says it’s the new oil seal on the back of the flange but why? Does the bearings have to be drawn in tight to seat properly?
It’s a mystery.
Next step will be to order the upgraded flange and seal but I can’t see why it’s gone wrong.
Any ideas??

You're supposed to set the pinion preload without the seal! Get it all correct then take off the flange and fit the seal.

boguing said:

You're supposed to set the pinion preload without the seal! Get it all correct then take off the flange and fit the seal.

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Ooooohhhh :-(
I bet that seal won’t come out easily without destroying it.

So I’m back home and have all the parts ready for fitting the diff pinion and preload.
I have some thoughts about getting the initial setting - can someone confirm my logic?

The original crush sleeve is almost exactly 2mm shorter than the uncrushed one, and the length of the sleeve is what is setting the preload.
The thread on the pinion is 1.5mm pitch (so 1.5mm of lateral movement per revolution).

It seems to me that once the nut is snugged up to close the gaps between the sleeve and bearings, I would in theory need 1 1/3 turns to crush the sleeve to the same size as the old one.

I’m going to use the correct method of setting the preload by torquing the rotation, but I reckon that if I start at 1 full turn of crush it will be pretty close (in theory needing a further third of a turn).
Is this logic correct??

Cheers,
Jim

boguing said:

You're supposed to set the pinion preload without the seal! Get it all correct then take off the flange and fit the seal.

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Can anyone see confirm this is the case?? It’s not what I had thought.

congo181 said:

Can anyone see confirm this is the case?? It’s not what I had thought.

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I've got to put my hands up and apologise - I didn't notice that it was a Salisbury diff.

I haven't done one of those, and whilst the F1 was on I've been looking at a manual and parts book to try and answer your earlier questions. I can't see why you'd have had any grinding.

Secondly, the manual I'm looking at asks if you've changed the bearings and gives two different preloads, so wanted to check that you had/hadn't.

boguing said:

I've got to put my hands up and apologise - I didn't notice that it was a Salisbury diff.

I haven't done one of those, and whilst the F1 was on I've been looking at a manual and parts book to try and answer your earlier questions. I can't see why you'd have had any grinding.

Secondly, the manual I'm looking at asks if you've changed the bearings and gives two different preloads, so wanted to check that you had/hadn't.

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I couldn’t do anything else during that race!! Mind blowing. Slightly unpleasant taste to the end but well done to Max.
So… yes it’s a Salisbury and I am not changing the bearings so will use the lower given torque settings (15-30ft/lbs). The manual does seem to suggest with the seal in place.

Have you got to the point where it grinds again?

No I’ve not started assembly yet.
Last time, I used the old hub and a new leather seal. I think I may I’ve distorted the metal seal shell which then rubbed on the hub.
I’ve now got the upgraded hub with a flange and the newer rubber seal so hopefully that’ll make the grinding a thing of the past.
I’ve just spent an hour turning the old hub into a holding tool - sadly I left the Mig gas on whilst I was away and it’s gone from full to empty. Bugger!!

boguing said:

Have you got to the point where it grinds again?

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I’m really having a mare with this pinion.
I assembled it all and tightened the nut up with the rattle gun until everything was seated, and then preceded to tighten up to crush the sleeve.
I had calculated I’d need 1.3 turns from snug to crush the sleeve to the size of the original, so I went to 3/4 and check the torque which was already at 50 lbf/“. Bugger.
So I took it all apart again, and the sleeve was still 1.5mm longer than the original - I’m expecting it to be crushed to about the same length if the preload is the same as before.
Reassembled again, same process, and the nut only needs a small go against the breaker bar to get to the required 30 lbf/“.
I’ve got a second sleeve, but this one is already 0.5mm shorter than the theoretical newly crushed one but still 1mm longer than the original. What’s going on?
Could the front bearing not be seating properly?

Any thoughts gratefully received. I’m getting quite ****y with this stupid job now.

As you have replaced the bearing and there can be small differences between old and new and different makes of bearing forget any measurement to do with the old spacer and fit a new one as per congo 181 instructions above

tottot said:

As you have replaced the bearing and there can be small differences between old and new and different makes of bearing forget any measurement to do with the old spacer and fit a new one as per congo 181 instructions above

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Ah but I’ve not replaced the bearings.
Only the crush sleeve, fling washer, oil seal, hub, washer and nut.
Can you confirm that I’m correct in my assertion that the length of the crush sleeve effectively sets the preload by spacing the two bearings?

When you asked " can the bearing not be seating properly " I assumed you had changed it and was asking if the new bearing race was not seated but as you have not changed it the only thing that could be is a foreign body in the bearing.[ unlikely ] Crush sleeve sets the load. The replacement being 1.5 longer is because there will be some wear in original bearing's and extra length is needed to take this up.

tottot said:

When you asked " can the bearing not be seating properly " I assumed you had changed it and was asking if the new bearing race was not seated but as you have not changed it the only thing that could be is a foreign body in the bearing.[ unlikely ]

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Understood

tottot said:

Crush sleeve sets the load. The replacement being 1.5 longer is because there will be some wear in original bearing's and extra length is needed to take this up.

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When I got the original preload set and then I inspected the crush sleeve, it had only shortened by 0.5mm, and still 1.5mm longer than the original.
What I don’t get is how a 1.5mm difference could occur unless the original setting was really out. I guess that could be the case?
1.5mm would change the preload drastically would it not? That’s a lot of wear.