How to replace Diff input bearing.

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Trewey

Cockernee, Pasty munchin bastid.
Posts
20,079
Location
Kernow - Near England
This is quite an involved job, but not too technical and is within the capabilities of a reasonably experienced DIY mechanic.

I did my front diff bearing. The rear one is a bit easier, because there is no need to remove the hub and stub axle in order to remove the half-shafts.

The first job is to drain the oil from the diff.
Then disconnect the diff end of the prop shaft.
Next, disconnect the half shafts from the diff. To do this, follow steps 1, 2, 5, 6, 7 and 8 of Buster’s Swivel Ball renewal thread http://www.landyzone.co.uk/lz/f41/swivel-ball-renewal-63808.html
(Buster removed his half-shafts completely – there’s no need to do this, just pull them out far enough so that they’re disconnected from the diff).
Some of the swivel oil / grease will leak out, so have something in place to catch it and remember to top the swivels up again when you’ve finished.

Next, remove the diff from the axle.
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It will need a good wiggle and a few taps with a hammer to break the seal.
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With the diff on the workbench, remove the split pin from the big nut on the input flange
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Undo the nut
4a35.jpg

and remove it
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remove the drive flange
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and the spacer
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Next, prise out the oil seal
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and remove the inner race of the input bearing. NOTE – there will be one or more shims on top of the bearing inner, don’t lose them and remember the order that things go in.
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Turn the diff over and loosen the 4 bearing retaining bolts – just “crack” them at his stage – about 1/8th of a turn.
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Mark the bearing cage – when you re-fit it, it must end up in exactly the same place.
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Remove the roll pin
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and the bearing locking peg
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unscrew the bearing cage by tapping it anti-clockwise COUNT THE NUMBER OF TURNS IT TAKES TO REMOVE IT AND MAKE A NOTE
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Do the same for the bearing cage on the other side – the number of turns might be different, so make a note of that too.

Now the bolts can be removed and the bearing clamps
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carefully remove the outer bearings (keep them on the same side of the diff when replacing them) and the crown wheel.
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now the pinion can be removed
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Working from the rear of the diff, the outer race of the input bearing can now be carefully tapped out with a punch or chisel (I forgot to take a picture of this). Tap gently and evenly, working your way around the perimeter of the bearing.
I then cut a slot in the old bearing outer, using a cutting disc on an angle grinder. This then makes a perfect drift for tapping or pressing the new one into place.
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I used a 52mm socket to tap the bearing outer into place, making sure it went all the way down to the shoulder.
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Now the pinion can be replaced
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and the crown wheel (re-fit the bearing outers too)
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Replace the bearing clamps
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and nip up the bolts (don’t tighten them yet – a little more than finger tight will do)
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replace the bearing cages – counting the number of turns and using the marks to get them in exactly the same place that they were originally
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the last bit will require a few taps
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Re-fit the locking pegs
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and the roll pins
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then torque up the 4 bearing retaining bolts
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Turn the diff over again and fit the new inner race of the input bearing AND THE SHIM(S) that were there originally.
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then re-fit the spacer
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Lubricate the new oil seal with some EP90 and push it in evenly as far as you can by hand
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then tap it down flush with a suitable drift
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re-fit the input flange
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washer
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and nut
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torque up the nut and fit a new split pin
4a35.jpg


All that remains is to replace the diff in the axle, re-fit the half-shafts (and whatever has been removed to facilitate that) and re-attach the prop-shaft.

DON’T FORGET TO RE-FILL THE DIFF WITH OIL AND TOP UP THE SWIVELS.
 
very informative:D

i like these how to guides, only thing is i got an oil leak on my back diff an you virtually told me how to do it,

more work:rolleyes:

can't wait to see what breaks for that job
 
cud get even worserer buster, that very informative picture manual by trewy will cover your front axle but not your rear one
 
Hi Trewey first of all what a good write-up well done.

Can I just ask - what made you do this? Reason why I'm asking is that I think I have a noisy diff on one of ours and I'm wondering if this bearings job will tame down the noise - what do you think?

Cheers
Dave
 
Mine wasn't noisy, but there was side-to-side play.
Does yours whine, clonk or rumble?
I'd whip out the diff and have a look first.
 
Mine wasn't noisy, but there was side-to-side play.
Does yours whine, clonk or rumble?
I'd whip out the diff and have a look first.


The problem I'm having with my latest Disco (1999 TD5 auto) is transmission whine, no clunks no rumbles..

Difficult to locate, but it only started after I had emptied the rear diff oil to replace with new. So I wondering what was in before, banana skins????
 
Yeah infact theres a thing in this months LRM which is interesting. The guy assembles the diff and puts some of that engineers blue on four of the teeth on crown wheel then he turns it a few times, it makes an oval shape on each of the teeth, the oval is in the middle, covering most of the tooth, if it is wrong then you can get contact on only part of the tooth towards the edge (hard to explain, the photos and diagram in article are easier to understand) The pattern is on the tooth on the crown wheel btw. If you are taking your diff out then clean it all off properly get some engineers blue and put some on the crown wheel teeth, turn it a few times and look at where it makes contact, if it is way out i think it would be fairly obvious. If you are going to take it all apart then at least you can see how it is now and how it is afterwards anyway, surely cant do any harm. As for the main input bearing, if that is shot i think you would have oil seeping past the seal. If you cant find any better info on the net or something pm me your adress and i can send you the mag in the post, its only a couple of pages but it is an interesting read, and i dont know if you can get it over in france very easily? Oh the reason i suspect whining is the diff itself is because if the gears arent (meshing?) properly they will chatter/whine. If you end up pulling it out and using the blue stuff please post pics, wouldnt mind seeing the result.
 
Oh sorry, you adjust the diff with them adjuster nuts, the ones you mark and count turns, the reason obviously for counting and marking is to put them back as they were. This is from thr mag: "The procress to be followed here is quite critical but it's logical when you think about it. The bearing adjuster on the opposite side to the crownwheel is backed off quite a long way and then the adjuster on the same side of the crownwheel is tightened using the correct spanner, pushing the crownwheel against the pinion untill you can only JUST feel no backlash between the prop flange and the crownwheel when trying to turn one against the other. Then the adjustment nut on the opposite side is tightened up again, in effect pushing the crownwheel AWAY from the pinion untill you can just feel a little backlash" It does say the expert demonstrating this can be trusted to assertain what is the correct amount of backlash, and a proper workshop guide should be used......
 
Theres a few pages in RAVE (I'm looking at disco 1 though). I havent read it but it looks like theres some useful info and it has a list of part numbers for shims.
 
A shameless :bump:

but used this this morning - superb guide, many thanks Trewey


Ratty/Si/Ods - know it isn't a 'Busters', but could this be archived among his other guides (sure B wouldn't mind:)) - sure it would help others
 
Replaced the oil in me front diff last week. What came out was just sludge and Scratchy has now developed an oil leak out of the diff input and on closer inspection there's a fair bit of play there n'all. Guess I'll be following your guide Trewey... How long did it take you..?
 
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^^ One post, trolling twit!

Replaced the oil in me front diff last week. What came out was just sludge and Scratchy has now developed an oil leak out of the diff input and on closer inspection there's a fair bit of play there n'all. Guess I'll be following your guide Trewey... How long did it take you..?
read the manual and set the diff carrier bearings properly its not difficult and dont punch the bearing races in
 
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