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 Midget and Sprite Technical - propshaft/gearbox disconect help!!

In the process of exchanging gearboxes, have done all the usual stuff ie striped the engine of linkages, removed rad, taken out gearbox mounting bolts, disconected speedo etc ( have had lots of usfull advice from Mark Boldry.) Have read the archive on how to disconnect the propshaft and they read as if there should be a hole in the undertray through which to reach the u/j. The undertray on my 68 Sprite is solid from directly below the instrument panel until just ahead of the diff am I missing something? Also some contributers have done the job from above and I am used to working with akward to get at parts but I can't even see the bolts. Any advice would be great as Mark is somwhere down under at present. Anybody else up yet?

John
J H Oulton

As far as I'm concerned, first you mark the position front and back (tipex or similar), where the propshaft meets the gearbox and also the diff. Then just undo the four bolts where the propshaft/UJ meets the diff then just drop the propshaft a bit (or move it to the side) Then just slide the propshaft out the back. There is nothing to undo at the front and the propshaft just slides into (and out of) the rear of the gearbox.
Someone will correct me if I've got that wrong.
Gary Lazarus

Gary is spot on; it's the 1500 that bolts up at the front of the shaft, the A series is a sliding spline. Do drain the gearbox oil first otherwise you will have pints of gear oil on the garage floor and in the tunnel.
David (davidDOTsmithAT stonesDOTcom)

And that's why there was never any hole in the bottom of the tunnel until the 1500 - though Heritage shells come with the hole in them regardless to judge from those I've seen.
Paul Walbran

Yes slides out of the gearbox rear when you disconnect from the diff. As said be sure to drain the gearbox first as the prop shaft makes the oil seal at the rear so when it is pulled out all the oil will follow. :-)

It is a bit of a problem to get back in at the gearbox and the hole under the gearbox end fitted to 1500 shells and heritage shells is a real godsend for this purpose, although with patience and ingenuity it does go in.

Finally I do not subscribe to the school of marking the flange connections at the diff. This is done by some to ensure the flanges go back together exactly in the same orientation as original. Due to the fact that the propshaft was never balanced with the diff in the first place it will not matter a toss as it is balanced as a seperate unit. I bet you someone will suggest differently but I have yet to have a problem doing it without any marking!
Robert (Bob) Midget Turbo

I must admit that I did mark the propshaft when I took mine out but after changing the UJ's I could no longer see the mark anyway and I agree with bob that it didn't seem to make any difference.
Gary Lazarus

Paul,
I used to believe that, too, then I had a late 74 A-Series midget that had the factory hole under the u-joint despite being a ribcase trans. I imagine they designed the hole for it and the stamping company immediately implemented it so as to not miss any. The hole is convenient for reinstallation of propshaft as well as for greasing the u-joint, so I think it is a good thing to have them in the heritage shells... if I could only afford one.

I also agree with Robert about being too worried about aligning things. Never cares a lick as long as all four bolt holes line up properly. No way to mark the trans anyway...
David "don't remember the VIN" Lieb
David Lieb

Many thanks to everybody for the advice. Turns out whilst flicking to another section of my haynes manual I wen't back to the wrong piece on engine & box removal (1500 not 1275) hense my confusion. Have now diconected the propshaft in the correct place(the bolts wer b*"#*#ds to release but are all out now. I had allready drained the engine and box. If all goes to plan it should be out early tomorrow.

John
J H Oulton

As I understand it, marking propshaft components really only applies to the yokes of the U-joints, and not to the flanges. Robert's right... the propshafts were originally balanced as a unit.

And I can state from experience that if you mark UJs, use a small file. When I replaced my UJs a while back, I used a Sharpie pen. And by the time I'd finished wrestling with the thing, the marks were long gone and I ended up getting the rear UJ back together 180 degrees out. Ha ha... so it was back out with the shaft and back to the workbench.

-:G:-
Gryf Ketcherside

Not sure if it should have been done but I did enlarge the front u/j lubrication hole on my Frog to the same size as the tunnel grommet to the gearbox fill. This was just large enough to get a hand thru to re engage prop following uj repair. Redundant now though with 5 speed. John
J R Clark

This thread was discussed between 30/08/2009 and 31/08/2009

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.