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 TD TF 1500 - Unusual diff failure?

My recent TF diff failure seems to have been due to fractured pinion pin locking bolt which allowed the pin to drop down and partly engage the pinion gear - ouch!

One of the crown wheel teeth was also broken off in the process.

See pics at http://mgjohn.com/tfdiff/

Look carefully and you'll see the broken off point of the locking bolt in one pic.

Is this fairly common point of failure?

Cheers, John
John Thomas

I have never seen or heard of this happening. Looks like a one time fluke. Contact me direct by e-mail. I may have some more info on this. I'll have to look.
John Masters

Ouch!
Growler

Further investigation confirms that the locking screw that is inserted into the planet carrier to retain the shaft on which two planet gears rotate did fail.

This allowed the shaft to move out of the carrier and engage the pinion gear - ouch.

It would appear that one of the planet gears 'picked up' on the shaft placing a rotational force on the shaft sufficient to break the pin that was there to stop it turning.

Friends suggest that this might have been the outcome of me failing a restart on Honeycombe a slipery hill on the Kimber Classic Trial that I was competing in when the problem occurred.

In attempting the restart one rear wheel was turning furiously whilst the other was stationary and I let this situation continue for too long when there was no realistic chance of getting going. This could have caused overheating of the shaft which may have been temporarily starved of oil due to the incline.

So it was really all down to my doing a trial with new Michelins on the back :-)

Incidentally the Honeycombe section was used on trials in the 'thirties when Cecil himself probably sailed up it, but he'd have been using a car more suited to the task than a roadgoing TF :-)

jt
John Thomas

Were you using synthetic or conventional gear lube?
Len Fanelli

Len the axle had Castrol EP-90 in it, changed about about 18 months ago.

The planet gears are not bushed, they just run steel on steel.

It's a fairly well exercised TF and we won the MGCC Speed Championsip (sprints and hillclimbs) last year.

http://www.bath.ac.uk/~ccsjst/gifs/jt_mgtf3.jpg

It's the 37th one built (17/9/53). Spent most of her life in Pennsylvania and Colorado in the hands of the Macurdy family, returned to UK in '91

John
John Thomas

This thread was discussed between 14/05/2002 and 17/05/2002

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.