The Triumph Dolomite Club - Discussion Forum

Hello good people.

I’ve been tinkering on the Sprint today, time to sort the diff pinion oil seal as it has clearly been leaking for a while. Having read a few different threads on this forum on the subject I was ready for a battle with the large nut under the metal cover. To my surprise it was only just over hand tight! This Is not good news I take it? I had marked it up so that I could tighten it back to the same position. But that clearly isn’t the position it should be in!? I don’t know the condition of the diff as I haven’t driven the car so don’t know if it’s whining or similar. But I guess it must have been noisy and that the nut should be tighter?

So what to do? Tighten the nut back fully? I don’t fancy having to strip the diff out to get it set up professionally if possible. Any ideas?

Also the seal I have bought doesn’t have a backing washer on it as per the original. Is this correct to use? Photo below, old seal on the right. Do you fit the seal dry or with a little grease or hylomar?

Cheers, Bish.

I read this thread with interest as I'm just about to try tackling this job on my Toledo - which admittedly has a completely different style of rear axle. But I have a fair amount of trepidation doing something I have no experience of, for the first time On the Toledo the spec is 90 lb ft which is reasonably tight, have you checked the book for the Sprint figure? The Toledo one is held on with a split pin too.

I have the same problem, I have never used the axle so I have no idea if it whines, but I reckon it's worth replacing the seal while I have the axle off the car and it's easy to do so, the current one is at least 40 years old if not the original.

Good thinking Chris. I didn’t think about checking the book All the info I’ve read about changing the seal has advised putting the nut back to exactly the same position as it had been previously. Maybe 10 degrees tighter. No mention of torque.

The book says; tighten to pre load of 29 lbf in with oil seal fitted. So I’ll guess that’s what I will do and hope for the best. 29 doesn’t seem to be a hefty figure so I guess that’s why it came off so easily?

Thanks for the reply and good luck with yours. It’s a pretty simple job. Hardest part for me was getting the old seal out. I had to destroy it with a hammer and small chisel before it would budge.

Hopefully I will get the new seal and a new cover gasket on tomorrow and another job can be crossed off the list

Hmmm! The torque figure is 90 lb ft for the Sprint pinion nut. But, the Sprint uses a collapsable spacer. Your nut is loose and, if there are no aligning marks made by the last person to install the nut, then you have no idea how much to tighten it. If you were to tighten it to 90 lb ft then you would move the pinion shaft forward and thus change the contact patch of the gears. You could renew the collapsable spacer and the axle may be fine (not noisy). That's what I would do in the first instance. If it's still noisy then it's only the cost of the spacer.

Edit: The pre-load is the force required to turn the pinion in the axle with no load ie. axle on the bench, no crown wheel fitted, not the torque figure of the nut. The figure is in lbf in not lb ft.

Both sprint and 1850 type have on the early ones shims to adjust the preload and the later ones a collapsable spacer and both types have different torque figures. I do not have these by hand.

The shim type is a solid preload where the torque isn't that importand as on the collapsable ones the torque of the nut does determine the preload on the bearings. When taking out the bearing behind the seal you can see what type of preload setting type you have as the collapsable spacer is just behind the bearing.

Jeroen

I have never seen a Sprint diff. which uses shims Jeroen. I've had a few early ones but they all had collapsable spacers. It's easy to tell which you have. If you have a castellated nut it will have shims. If you have a nyloc nut it will have a collapsable spacer.

Thanks for the advise Mart and Jeroen. Now I understand what the pre load figure relates to.

I have a nyloc nut. It’s a 77 year of manufacture car. So I need a new collapsable spacer and nyloc nut and tighten to 90lbs ft? I guess it’s then a case of see how it goes when the cars back on the road. Fingers and toes crossed!

Collapsable spacer sits behind the bearing that I can see now I’ve got the seal out? Will the bearing simply pull out now?

How about that new seal I’ve got, is that ok to use? Just a different design to the original?

Cheers, Bish.

Bish wrote: ↑Thu Jan 03, 2019 12:55 am Thanks for the advise Mart and Jeroen. Now I understand what the pre load figure relates to.

I have a nyloc nut. It’s a 77 year of manufacture car. So I need a new collapsable spacer and nyloc nut and tighten to 90lbs ft? I guess it’s then a case of see how it goes when the cars back on the road. Fingers and toes crossed!

Collapsable spacer sits behind the bearing that I can see now I’ve got the seal out? Will the bearing simply pull out now?

How about that new seal I’ve got, is that ok to use? Just a different design to the original?

Cheers, Bish.

I just had a quick google search of this and I don't think it is as simple as fit new space and tighten to 90lb ft torque. People are talking about setting up based on the preload of the pinion. That 90 figures seems to be an initial starting point, with the nut then tightened until you get the correct preload, with a max setting of 120.

This is why I don't go near diffs, far too difficult to setup. Of course I am probably wrong and someone who knows what they are doing can give you the correct procedure.

cleverusername wrote: ↑Thu Jan 03, 2019 10:39 am

Bish wrote: ↑Thu Jan 03, 2019 12:55 am Thanks for the advise Mart and Jeroen. Now I understand what the pre load figure relates to.

I have a nyloc nut. It’s a 77 year of manufacture car. So I need a new collapsable spacer and nyloc nut and tighten to 90lbs ft? I guess it’s then a case of see how it goes when the cars back on the road. Fingers and toes crossed!

Collapsable spacer sits behind the bearing that I can see now I’ve got the seal out? Will the bearing simply pull out now?

How about that new seal I’ve got, is that ok to use? Just a different design to the original?

Cheers, Bish.

I just had a quick google search of this and I don't think it is as simple as fit new space and tighten to 90lb ft torque. People are talking about setting up based on the preload of the pinion. That 90 figures seems to be an initial starting point, with the nut then tightened until you get the correct preload, with a max setting of 120.

This is why I don't go near diffs, far too difficult to setup. Of course I am probably wrong and someone who knows what they are doing can give you the correct procedure.

Yes, what you say here is correct. That's why I said it may be fine.

When the bearings are ok it will be fine. There's nothing scientific about my methode but when it feels unnatural tight the preload is ok. When you change the seal and tighten again till your own mark methode has the same inaccuracy as the preload dissapears by wear and most don't have enough preload by far anymore after 50.000mls. One time i fitted a shim before the collapsable spacer to be able to collaps it again. A diff is a diff and nothing more. You don't alter any gear settings by setting the preload.

Jeroen

soe8m wrote: ↑Thu Jan 03, 2019 4:57 pm ...You don't alter any gear settings by setting the preload.
Jeroen

Jeroen is correct, senior moment from me there, the preload is just on the bearing. The pinion drive to crown-wheel is changed by using shims on the inside of the diff.

Thanks again all for your input.

I’ve taken the diff cover off and found no noticeable odd wear patterns, or damage to the inner working of the diff. It all looks good.

I don’t think the bearing will come out through the pinion oil seal bore. I’ve had a fiddle about with it but can’t get it to budge. I was going to remove it and fit a new collapsable washer, but if that’s not possible I will fit a new nyloc nut and tighten to 90lbft and see where I am.

Fingers crossed!

Bish wrote: ↑Wed Jan 02, 2019 7:50 pm Thanks for the reply and good luck with yours. It’s a pretty simple job. Hardest part for me was getting the old seal out. I had to destroy it with a hammer and small chisel before it would budge.

Thanks for the encouragement, I'm half way through destroying my old seal too, it won't budge! I'll give it another try in the morning once it's had a soak in penetrating fluid.



How did you get on with the new suspect seal? For the Toledo the pinion oil seal is 141242 which I believe is superseded by DAM5079; the picture of this on Rimmers looks like your new one, and also nothing like my old one.

Since the preload is supposed to be set to the value given WITHOUT the crownwheel and diff in place, you can only guess at a sensible preload anyway. The pinion shaft bearings are taper rollers, wear in these is what causes loss of apparent preload and, I suspect, that this is what is responsible for your pinion flange nut appearing to be loose. You can reset a preload into it, but if the rearmost pinion shaft bearing is worn (which no visual inspection short of total dismantling will show) the crown wheel to pinion mesh will not be correct and may result in noise.

I'm certain that the front bearing race can be removed through the pinion flange hole (once the seal is out) as that is how it is fitted on initial build, but it may be WELL stuck on the shaft and difficult to dislodge. I'd be inclined to try refitting the flange and tapping it sideways to dislodge the race.

The ONLY way to be sure is to replace the 4 main critical bearings and re-set up the diff as per factory. But there's nothing lost by giving it a go as it is, either it's quiet and you've got away with it and saved a wedge of dosh, or it's noisy and will need a rebuild (or another axle) which it almost certainly did before you started! Just, if it IS loud, don't drive it long like that or you WILL write off the CWP too!

Steve

When I was an apprentice I made the bearing extractor shown in the photograph and I have used it for both removing the rear axle pinion seals and as shown in the photo O/D rear seals.