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MG MGB Technical - 3.9 diff rebuild

Am preparing it for a race car. The unit is on the bench and I only need to take it apart, clean and replace bearings if necessary. Have removed the 4 bolts holding the cradle type pieces but cannot separate them. Any suggestions?
te davis

The Workshop manual talks about an axle stretcher being needed in order to remove the bearing caps over the diff bearings and hence the diff. This effectively pulls the two tubes apart fractionally. However this only comes into play once the caps have been removed, i.e. to remove the diff assembly itself.

I've dismantled one without that, and I know others have too, so perhaps yours just need a bit of 'encouragement'. Perhaps by attempting to lift out the diff while they are still in place (bolts removed, obviously). Mark the caps for position and orientation before removal.
Paul Hunt

That only applies to the later "tube" axle and I have never known one to be needed.

Once the bolts are out then the bearings caps can be gently tapped off - they may of course have been fitted in the past with Loctite or similar!

Beware that taking a diff unit apart may upset its alignment and resetting is a fiddly job requiring some experience and in the case of the pinion bearing some special tools.
Chris at Octarine Services

Give the caps a few wacks with a good plastic hammer on the sides just above the joint line. Repeated hammering will walk the cap up the studs.
Mike
Mike Ellsmore

Thanks a lot for the comments. I did give it some taps with a hammer on a piece of wood. It was stubborn but after releasing its hold I was able to walk them up the studs as mentioned above.
This is an older diff. After I got the caps off I carefully removed the pinion gears and noticed each one sits on a spacer. I marked the front and back gears so they will go back as removed. Any other hints to getting the fiddly (I am aware of the pitfalls) thing together so it works OK?
te davis

Read the Workshop manual and pages on MGAGURU
http://mgaguru.com/mgtech/rearaxle/ra1.htm and you should be okay.
Mike
Mike Ellsmore

Great stuff! Thanks. Answers all my questions.
te davis

This thread was discussed between 23/02/2014 and 28/02/2014

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