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MG MGA - Differential Front end leak

I have now had my 3.9 Differential in the car and working very nicely for the last 5 days. However, I appear to have a small leak through the front oil seal. The oil level in the casing is correct, so the cause is not due to overfilling.

Can I remove the the U/J flange and dust cover to change the oil seal without upsetting the crown wheel/pinion set-up? Also can I do this insitu or do I need to remove the pumpkin to the workbench?

Steve
Steve Gyles

Steve,

It can be done in situ. It will not upset the the Differential set up. You have to determine how you are going to stop the flange from turning while you undo the nut.
There is a special tool or you could make your own, with two flat bars with a hole drilled in each end. One end of each bar fitted to flange bolts holes and the other ends bolted together to form a "V".
I suppose you could just have another person apply the brakes, but this is not my preferred method.
Check for wear on the flange where the seal runs, if grooved it could be the problem.
Ensure that you fit the seal facing the correct way.
Seal replacement is covered in the Workshop Manual (or at least it is in my Twin Cam Manual).

Mick
Mick Anderson

Thanks Mick. Almost sounds a similar idea to the one posted last week about undoing the crankshaft nut!

I am guessing that the new oil seal will be a standard MGA item and not specific to the MGB - from where the 3.9 diff came (everything else in the diff seems identical).

Steve
Steve Gyles

A quick check of the Victoria British catalogue confirms the same P/N for the diff oil seal for the 'A and 'B banjo axles. I've the same repair to do on mine.

TTFN

Derek Nicholson

Mick

I made up the tool last night re your instructions. Looks good. Just waiting for the new seal. I spoke to Bob West. Apparently it can be one of those jobs that's all done in an hour. Alternatively, it can be a real sod trying to pull off the U/J flange.

Steve
Steve Gyles

Steve,

You must keep the seal square (at 90 degrees) to the housing. You need a good drift. The best type would be an old forward pinion shaft bearing. You should be able to find something similar.

Mick
Mick Anderson

Steve

Please post a picture of the tool on your odds and sods page.

dominic clancy

Dominic

Will put it on tonight. Perhaps Mick can then tell me if I have got it right!

Steve
Steve Gyles

The tool is now in my Odds & Sods: http://freespace.virgin.net/stephen.gyles/odds_and_sods.htm

Steve
Steve Gyles

Steve,

That tool looks OK.
Remember the three things about oil seals:
Face the seal the correct way,
Have the seal "square", that is at right angles to the bore and shaft,
Wipe the lip of the seal with oil when fitting.

Mick

Mick Anderson

Mick

I was going to do the job last weekend. I got the Workshop Manual out and read the appropriate bits, but then noticed that the nut is torqued to 140 ft lbs. That might be ok if you have the car on a lift/ramp and can pull down vertically, but I judged it probably impossible for me with the car on axle stands and trying to pull 140 lbs horizontally lying on my back with a one foot wrench. It also concerned me that I could possibly pull the car sideways off the stands.

Does anyone have a success story that could convince me otherwise?

Steve
Steve Gyles

I managed this using a scissor jack to apply the load upwards to the end of an 18 inch torque wrench. The tool bolted to the flange was braced against the garage floor. I operated the jack handle from a safe position outside (not underneath) until I heard the torque wrench click.

The car did not lift off the axle stands as I had feared it would. However, it was a Magnette not an MGA.

Andy
Andy Dear

Thanks Andy. Good bit of lateral thinking.

Steve
Steve Gyles

This thread was discussed between 22/08/2006 and 30/08/2006

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