MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - How to remove Diff nose nut

Can anyone give any tips on how to loosen this nut to allow replacement of the oil seal at the front of the diff?
dominic clancy

Dominic,
I presume the axle is still on the car, if so I have found that if you have the handbrake on hard and some good blocks fore and after the wheels with a good long handled ratchet it should come free (car on garage bridge)

Clive
Clive Skelhorn

I have one on the car, and one off which has a different ratio.
dominic clancy

If you have access to an Air Impact wrench, it will break it lose and come right off in seconds. The fast "jarring" action if the impact will break it lose.

DT
Danny T

Dominic,
I used the impact wrench but I also made a bar that bolted to the flange in two places. When attached and wedged on my table it would stop the diff from rotating while trying to remove the nut. Have a good day.

John
John Progess

John, that's the way I do it too.

I have nightmares about the impact wrench hammering the gear teeth against each other and possibly introducing fractures. Maybe not a realistic concern, but by locking the flange I can at least try to eliminate one more excuse for the car to screw up......;-)
Bill Spohn

I have had luck with a bar bolted to the flange as has allready been mentioned. Tension your nut with a breaker bar ( ie: put your weight on it ) and then pour a kettle of boiling water on the nut. Works 9 times out of 10....
Mitch Smith

If you are just replacing the seal, it is wise to mark the nut and shaft with a punch mark so that you can tighten it back to the same position and not affect the preload on the bearings. If you are replacing more that the seal you will have to reset the preload anyhow.
Ed Bell

This can be a bear of a job and if you dont lock the flange you will end up winding up the diff and the whole housing moving all over the place. Make a bar that can be bolted to two of the flange nuts and grind away the centre for clearance for your socket. Put a breaker bar on the socket and you will be able to pull the two together to slacken the nut. It will still be extremely tight and heat could certainly help as well. Marking the nut, pinion and flange is vital before you start then put it all back so that the marks line up again. If you tighten beyond the mark the collapsible spacer is bug....d and you will have to pull the diff apart to replace it, so be warned.
Iain MacKintosh

The banjo axle does not have a collapsible spacer - only the Salisbury (tube axle) has one. When replacing the flange, it is not necessary to mark the relational positions of the flange and pinion shaft for either balance or torque.

while the seal is out, it is a good idea to pull the front pinion shaft bearing to check for wear and excessive heat discoloration. Be careful to put any shims back in the same order they were removed.

Personally, I prefer the impact tool removal. If you use a torque wrench to tighten the nut to spec's, you will have to fabricate a tool such as the one Iain describes. brakes alone will not lock the differential for tightening - too much mechanical advantage favoring the pinion gear. I use an impact tool with the parking brake on for tightening and have had not any problems.

Steve
Steve Brandt

I undid mine recently using a 3 to 4 foot length of steel strip about 1" by 1/8" with a hole drilled close to one end which is bolted tightly into one of the flange holes. Holding this in one hand plus a 2 foot torque wrench in the other and hey presto! Mike
m.j. moore

Hi Mike,

I hope that was an error when you said that you undo the Differential nut with a torque wrench. A torque wrench is a calibrated, precision instrument, or it should be.
It must never be used for undoing nuts, that is where breaker bars are used.
I hope that you do not use it to measure preload on bearings after such a use.
In my brother's engine and transmission rebuild business that is one of the first instructions new employees receive. Get caught once and you are back amongst the unemployed.
You can take your cigarette break while sitting on a drum of petrol, but never undo nuts with a torque wrench!

Mick
Mick Anderson

Hi Mick, Whilst I agree with you in principle especially for a professional mechanic who would use a torque wrench almost daily I guess that most of the guys on this site are, like myself, amateur and probably use their torque wrench (if they have one) a few times a year at most. Also I can't see what damage it could cause to the wrench provided it is set at maximum torque and it is not taken beyond this in undoing a nut. The wrench is not really doing anything different in undoing compared with tightening.


Cheers Mike
m.j. moore

Hi Mike,

The problem with using a torque wrench to undo nuts is related to a property of torsional forces in metals known as "set" or "settling". When a metal rod is twisted, even within what in engineering is called the elastic limit, it never quite returns to the original position. This difference is extremely slight, but increases with multiple use. Vehicle examples are drive axles, suspension torsion bars etc. Over time they "settle". New axles and torsion bars may be used on either side of the car, but once used must always go back on the side from which they came.
Due to this settling we have our torsion wrenches calibrated once a year. The change over time is small, but important. If used to undo a nut they would have to be recalibrated. With an engine having a cast iron head and block it may not matter much, but with small engines using alloy heads and blocks, or when measuring bearing preloads, it becomes important.

Regards,
Mick
Mick Anderson

There are generally 2 types of torque wrenches that a car owner would use. The newer type that you dial up the torque and tighten the fastener up until it clicks. This type must not be used to loosen fasteners as it damages it like Mick said. The old fashioned bending bar type may have numbers on it's face for both directions. I keep one on hand to torque left hand fasteners. This type is not damaged by going either direction and could be used to loosen something that you want to see how tight it was. Don't bend this type further than the scale on it. Never strike any torque wrench. Use a breaker bar it is the proper hand tool to abuse.
The old type is more tolerant of abuse and more appropriate for casual use.
My box contains a 1/2 and 3/4 ratchet drive click type torque wrenches that are always stored unwound and in special boxs. They get most of the use. I also keep a 1/2 and 1/4 drive beam type wrench for infrequent use and special needs.
R J Brown

This thread was discussed between 12/02/2006 and 16/02/2006

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.