MG Car Repair: 1977 MK 4 midget gearox, british car repair, car repair shop

Question
QUESTION: I've dismantled gear box everything is out except laygear & main shaft. I can't seem to move main far enough to rear in order to remove gears, 1st gear stops me. how do I get main shaft out of housing.

ANSWER: Hi Steve,

Did you drop the laygear down to the bottom of the box and remove the rear bearing off of the mainshaft, then remove the mainshaft up and out of the top?

Howard

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QUESTION: Dropped laygear and have removed 1st motion (input)shaft and mainsshaft bearings but the mainshaft appears to be one long piece. Book seems to intimate that it should come out top but I see no place of separation on the main S

ANSWER: Steve, if you removed the rear main shaft bearing, the front of the main shaft with all the gears on it will lift up and out the top. It sounds to me like you have not removed the rear main shaft bearing. Another reason I think you have not removed the rear main shaft bearing is that you have not asked how to do that, as it is not obvious how to get it out.

With the rear main bearing out the hole in the back of the case is 3 inch + and the main shaft will tilt easily in a 3 inch hole and allow the front to raise and come out of the top and then just slide the rear of the shaft up and out of the top.

Howard

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QUESTION: Went back looked closer. 1st gear had slid to rear after sliding it forward again I was able to get shaft out. Thank you
Found bad reverse mainshaft gear moss#071-342. Every where I look it is unavailable. I have a 21 tooth reverse idler and a 33 tooth on the main shaft gear. any ideas on where to get it?

Answer
The only way I know is to search the Internet as there are many more parts suppliers then Moss out there. I am not sure if the distance between the idler shaft and the main shaft are the same on other model spitfires or not but if you can locate a local British car repair shop you may get lucky and find one that has some used gears so you could do some fancy measuring and see if one of the older boxes has different ratio gears that all three might be installed used. If they can be switched new gears would probably cost more then the box is worth but used might not be too costly if they fit. I never tried it on a Spitfire nor a late model Midget.

Howard