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 - 2nd gear bulk ring (synchro)

Hello all,

During the restoration process of my mkII that is being sorted for vintage racing, I've found myself contemplating the possibly nasty task of replacing a 2nd gear bulk ring or synchro. I've read the manual and it looks like I may need 4 hands to do the job what whith all the little springs, and things.

It looks to me as though once the 3rd motion shaft is removed that you have to begin at the 4th gear end to get to the 2nd gear end of the works.

Long story short, is there a EASY (yes I said it) way to replace the 2nd gear synchro and check the layshaft for wear?

Thanks!
John

John Bries

Hi John. Unfortunately, there is really no easy way to replace the second gear synchro ring. You need to partially disassemble the mainshaft to do it. There is a small spring loaded peg in the mainshaft that must be compressed. When compressed, it allowa a splined washer to rotate, and then be removed. Once the splined washer is removed, the approprate parts are then removed in order, (from the front end of the mainshaft) until the second gear synchro ring can be removed and replaced. Assembly is simply the reverse procedure. There is an oil hole that needs correct orientation on re assembly. See the manual for details. As for checking layshaft wear, this is easy, once the layshaft is removed. Simply run your fingernail along the surface of the layshaft where it runs in the 3 sets of needle bearings. If you see or feel any roughness or wear, the shaft should be replaced. On a layshaft that is worn, you can usually see the wear with the naked eye. Again, if you can see or feel any wear, I would replace the layshaft, since it is relatively inexpensive. When the gearbox is rebuilt, I would use synthetic 20 W 50 motor oil, or redline brand synthetic transmission oil to minimise war. Hope this helps. Glenn
Glenn

No
Paul Hanley

John, while you are in there, does it already have close ratio gears? Almost a must for vintage racing.
racer

John

Went through this for the first time with my box last winter.

The layshaft will almost certainly need replacing with the bearings. It would be a mistake not to since the box will have to be stripped right down to check anyway.

The only difficult job was getting the circlips out of the laygear. I prised them out with a small screwdriver but one suggestion I read recently was to snap them by hitting them with a center punch.

When you pull the selector rods watch for the springs and balls, they will shoot out of the block never to be seen again.

It wasn't as difficult as I thought. Replaced layshaft, bearings and 2nd gear synchro and it has transformed the box. I found the job overall almost enjoyable.

Chris
Chris Paul Currah

John,
I did this exact same thing a couple of months ago.
It is far more frightening than difficult. The key to doing it is to do things in the right "order".
It is a 4 hour job for someone with experience. I probably took 20 hours. (You don't need 4 hands either.) But now I understand how the thing works.
I'd recommend that you get the Namgar reprints on the transmission rebuild. Also there are experienced people here who are very helpful.
It is one of those things that after you do it, you'll say that wasn't so hard afterall.
Jonathan

jonathan

The way to keep your balls and springs is to cover the whole thing with a dense cloth as you remove the shafts. The cloth will catch the balls and prevent them flying away. You just work blind with your hands under the cloth.

It save the danger of being hit in the face by a ball too.

dominic clancy

This thread was discussed between 09/10/2004 and 11/10/2004

MG MGA index

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