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MG MGB Technical - Propshaft flange

I have the gearbox and O/D out of the car (71 roadster) and I want to remove the prop shaft flange so I can change the Annulus oil seal. Any suggestions as to stop the flange from turning when trying to undo the large centre nut. Thanks
Trevor Harvey

Hello Trevor,

Very simple: two bolts in 2 adjacent flange holes. Use a lever(prybar) to lock rotation and remove large nut...

Cheers,

Jean G"
Jean Guy Catford

A length of angle-iron with two holes drilled in it, bolted to the flange.
Dave O'Neill 2

Fit the flange bolts loosely and trap the 'square' formed by the bolts in a Workmate, or similar. With the OD separated this is straightforward. With it still joined to the box the workmate will need to be laid on its side/end and suitable blocks employed.
Richard Coombs

The bolts that attach the flange to the prop shaft cannot be removed until the flange comes off, the bolts cannot pass the case of the overdrive. I have tried to use two of these bolts with a bar going through them but the central nut is so tight I fear I might bend or break them.
I might be able to do something using Richards idea.
Thanks
Trevor Harvey

The abo ve technique works great on midget differential flanges, whihc are torqued to 140 ft/lbs. I don't think you'll break the bolts.
According to Haynes, your nut should only be 55-60 ft/lbs.
Dave O'Neill 2

But you have a chance of bending them or the flange if you use Richard's method and it's really tight. Tighten the bolts against spacers, or much better, Make the tool! You'll use it again if you continue to play with these things.

FRM
FR Millmore

Just had a look in the Haynes manual and it actually has a photo showing a piece of 'Dexion' bolted to the flange to hold it, while undoing it with a socket.
I prefer to use solid angle-iron, as there is less chance of it bending.
Dave O'Neill 2

Sometimes you can loosen these sorts of things just with an air impact gun without much (or anything) needed to stop it from rotating. The shock just spins them loose.
Simon Jansen

But I cannot remove the bolts, they will not come off until the flange is removed. The casing of the overdrive stops them from coming out.
Trevor Harvey

Workshop manual shows a tool with four holes to engage the flange bolts and a VERY long lever. Four holes would be better as the bolts would then be loaded as they are in operation.

The two bolt method will probably work but could bend the bolts because you are effectivelu applying the whole force to one of the bolts - the one nearest the end of the lever you pull on or restrain - as the other bolt is acting as a pivot.

Sorry to ask, but have you removed the split pin? The workshop manual shows one. I've an overdrive on the floor in my garage, but there's mo split pin arrangement.

N
Neil22

Neil -
The force on the two bolts is exactly the same, but in opposite directions. If the bolts are tight, it is a straight shear load and you are not going to shear those special bolts. If you use a prybar or leave the bolts loose you can bend the bolts or the flange, or at least raise burrs that will throw the shaft out of line when reassembled. Usually the only damage is to destroy the threads on the bolt, and they ARE specials that cannot be replaced with the flange on.

Trevor -
Just make the bloody tool and use it. I personally have removed probably a thousand of these things with no trouble. If you are really worried, get a piece of plate and drill 4 bolt holes and a big center one to clear the socket, but it is not necessary. I have all sorts including a factory one, but my factory one is only for flanges with removable bolts - it has 4 reverse taper pegs to engage the holes. The homemade tool is better if it's really tight.

FRM
FR Millmore

"But I cannot remove the bolts"

You don't need to remove them, you use two of them and their nuts to bolt the bar or angle to the flange!
P Hunt

I have managed to get it off. I borrowed an impact gun, wound the commpressor up to 120lbs. and after about a minute it came undone. Thanks for the advice.
Trevor Harvey

Trevor,

I dislike impact gun for such task. As far I remember after removing large nut, using a long flexible elora handle( 2 ft). I used a puller to extract flange, a very easy task...
JG
Jean Guy Catford

This thread was discussed between 10/01/2010 and 13/01/2010

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