Differential oil seals and bearings

[foster461]

I started this over in the pinion oil seal topic but I can see I’m confusing people so I’m moving to a new thread and starting over..

 

I bought a used diff just so that I would have a spare. It is an early unit and seems in good shape except that it is leaking oil from both axle’s and the pinion seal. I realize that it is non trivial to take the differential apart and re-assemble it but all I want to do is put in new oil seals..

 

I was hoping that putting in new seals would be fairly straightforward but apparently not..

 

The pinion seal comes out reasonable easily after the mounting plate and pinion flange have been removed.

 

The inner axle assemblies come out reasonably easily after the four bolts attaching the housing are removed.

 

Now that I have reached this state I have two question:

 

1. Having removed the pinion nut and flange, has that buggered up the whole crown wheel and pinion setup, ie am I in the same state now as someone who has dismantled the diff and needs the special tools to set the thing up again or can I insert the new seal, slide on the flange and torque up the castelled nut ?

 

2. How the heck do you get the flange off the inner axle shafts ?. The shafts seems to be tapered and there is a key to lock the shaft onto the flange but I have the mother of all hub pullers attached to this thing and I cant budge it. The Haynes book talks about re-attaching the nut to the shaft and hammering it with the flange in a vice. That doesn’t move it either. I have tried heat. I’m wondering if it needs a 20 ton press or something.

 

 

This is just a spare so I’m not desperate but I would appreciate any guidance on how to proceed.

 

Stan

[Richard Crawley]

Stan,

Don’t worry, you have not buggered the unit setup by removing the pinion flange nut, unlike the rear hub units, collapsible spacers are not used. In spite of what the manual says, you don’t really need any special tools to strip the diff down & as long as you have a basic knowledge of mechanical procedures, you can get by. You will need an 8” or 10” engineers vice, a selection of long bars & tubes & a large torque wrench to set the massive 120lbf/ft torque loading on the prop shaft & drive shaft flanges.

 

You seem to have been a little unlucky with your flanges. I found pullers to be generally ineffective on the shallow tapers the TR designers used (the rear hub is almost impossible to separate without damage) & resorted to brute force & heat, as described in the Haynes manual. Mine came off easily but required some fairly hefty blows with a 4lb club hammer & a large lump of brass. You have to ensure that you hit it hard enough to shock it loose but not so hard that you cause damage! Try putting the shafts in the freezer overnight then try again; apply heat to the flange quickly & give it a good whack before the shaft has a chance to heat up & expand with the flange. It’s also important that the vice is mounted on a fairly solid base, mines mounted on a 1” thick lump of steel. If it’s fixed to a wooden bench, this tends to absorb the initial shock of the blow & hence it may not separate. If you can’t shift the flanges using this method, seek out a local machine shop with a press, they should only charge a couple of quid to press the flanges off.

 

I completely stripped my diff & rebuilt it with all new bearings & seals. Setting it up is fairly straight forward if you follow the manual but you will need a large torque wrench. I could not get hold of any engineers blue to set up the crown wheel so used a large felt tip pen to get the correct mesh pattern. It all worked a treat & my unit is as quiet as a mouse.

[Victor1155]

Hi Stan

Quite often when trying to remove tapered flanges with a hub puller a quite effective trick is to give the flange a good crack with a brass drift whilst it is still loaded by the hub puller. I had the same problem last week and the flanges gave way with an almighty crack and no damage. Good luck!

 

Victor1155

[foster461]

Thanks Richard, that is very encouraging although I suspect I'm going to seek out a machine shop with a press to help me with these flanges (I live close to Nashua, NH btw.) because my little bench and vice is not up to it.

 

Am I correct that the axle threads are both right handed, ie one side will be "normal" and the other will need to be rotated counter to what you would expect for a normal thread ?

 

And what about re-assembly of the axle/bearing/seal/flange, did they go back on any easier than they came off and what visual/mechanical clues do you have for getting the bearing and the flange into the right place on the axle ?.

 

Stan

[foster461]

give the flange a good crack with a brass drift

 

Actually I tried that with the puller and the heat thing at the same time and I moved the flange about 1mm. The only thing I havent done is put the whole thing in the freezer so I'll give that a shot before I give up.

 

Stan

[Richard Crawley]

Stan,

I think you are correct in that the threads are opposite hand but I can’t really remember; it’s easy to check the handing of the thread by looking at the end part protruding through the nut. You say the flange has moved about 1mm, it sounds as though it’s binding on the key! Every thing should go back without any undue force; once you get it all apart, check that the keys are in good condition & that there are no burrs or high spots on the key or the shaft causing the flange to bind. Have you got a BL manual? If not download one from the link given on this forum a couple of weeks ago.

[foster461]

Well, I froze, I heated, I hammered, I pulled. I swore. Then I took them to a local machine shop that has a 50 ton press. Picking them up tomorrow, hopefully disassembled and with the pieces intact.

 

Stan

[foster461]

One more question... I like the idea of adding a drain plug to the diff while I have it on the bench. I wonder where to put it though, in the bottom of the rear alu cover or in the bottom of the diff case, and what size plug to use ?. I thought I read somewhere that early models had a drain but I cant seem to find any info about its location or size..

 

I like the idea of drilling the cover since that is replacable but I wonder how well it would hold up over time..

 

Stan

[Richard Crawley]

I would have thought it would be OK to drill & tap the diff case at the bottom but if I were doing it, I would use a straight 5/16 or 3/8 UNF parallel set screw & copper washer rather than a taper plug. I don't see any difference between this & a standard sump plug fixing so it should hold up OK.

[foster461]

I got my axle's back from the machine shop. It look over 20 tons to crack the flanges off the shaft apparently but evrything looks good.

 

I'm curious about one other thing, the book says when dismantling the diff you need a special tool S101 to spread the case to allow the CW to be removed. I'm having a hard time visualising expanding that cast housing so I'm thinking I must be misunderstanding something and it is something else that is being moved. Is there an alternative approach ?

 

Stan

[Richard Crawley]

Stan,

the casing does not have to be expanded by much to get the unit out, if at all! The cross carrier & bearings are shimmed to make it a very snug, lateral fit but I found that with a little teasing, using pry bars & hard wood blocks, mine came out very easy without using tool S101. It also went back just as easily - several times as it happens due to setting up the new bearings & then the pinion mesh pattern. I put back the same shims on each side of the carrier & was lucky this turned out to be OK with the new bearings. My diff is now very quiet & smooth with no hint of backlash.

[foster461]

Well true to form this puppy is jammed in there pretty tight. A couple of foot and a half long bars doesnt budge it.. What kind of pry bars did you use and did you just hook them under the open sections of the carrier and lever away ?

 

Stan

[Richard Crawley]

Stan.

You don’t seem to be having much luck with the strip of this unit do you; or perhaps I was particularly lucky with mine. I used a large & very old boiler makers screwdriver (it’ virtually indestructible & tends to double as both a chisel & jemmy) + a pry bar made from an old lump of 5/8” tool steel; both are around 1ft long. I put the diff in an 8” vice & levered underneath one of the crown wheel bolts on one side & (with a lump of nylon to protect the teeth) under the crown wheel on the other side; I levered against a couple of ½” steel bars spanning each side of the dif case, with hardwood strips placed either side to protect the diff cover face. It did not take that much effort to move the carrier unit off it’s seating & it then moved progressively easier all the way up. The interference fit of the carrier unit should only be around 0.003” so you could try the overnight freezer trick again which may give you just enough to jar it off the seating.

[foster461]

:-)  The crown wheel and pinnion assembly is out !. I bought a couple of pry bars (Stanley brand...) that were about 2 feet long and have one straight end and one bent. These could get enough purchase and had enough leverage to ease the crown wheel assembly out of the case.

 

Next question.. The outer sections of the two pinnion bearings are still in the case. Bently shows a couple of special tools for removing and inserting these things but I assume they can be drifted out ?. Also which direction to they come out, do they both get pushed into the case ?

 

Stan

[marvmul]

These bearings are pressed onto the short axle shaft. When you remove the 4 bolts of the bearing housing, the bearigs will come out together with the axle shafts.

[foster461]

These bearings are pressed onto the short axle shaft. When you remove the 4 bolts of the bearing housing, the bearigs will come out together with the axle shafts.

 

I was actually interested in the pinion bearings, there are two of them, one that appears to come out from the front (prop shaft flange end) and the other that comes out with the pinion once the crown wheel assembly has been removed. The outer cases of these two pinnion bearings are pressed into the case and I wonder in which direction they need to be coerced out and if they will come out with a drift.

 

Stan

[marvmul]

The 2 bearings are pressed to each other by the nut on the pinion that holds the flange for the propshaft. They have a spacer and shims between them. So I think that the front bearing comes out  via the front end of the casing.