Mainshaft removal

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Rust bucket
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Mainshaft removal

Postby Rust bucket » Wed Jul 03, 2019 11:32 am

I bought what appears to be a good spare gearbox and just want to check it over to make sure. Down loaded the PDF manual for assembly but how do you remove the mainshaft, didn't think I could remove it without getting the reverse gear out but I understand now there is a cut out for clearance. The bearing housing looks to be lined up ready for withdrawl from what I can see, it does start to move about 1mm but only one side, stuck fast the other. Please see pictures, thanks.
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DSCN2240.JPG (403.52 KiB) Viewed 161 times

newagetraveller
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Re: Mainshaft removal

Postby newagetraveller » Wed Jul 03, 2019 1:21 pm

Remove the front bearing cover.
Pull the lay shaft out from the front (I attach a mole wrench and twist and pull. The lay gear should drop down a little bit. )
Withdraw the third motion shaft from the back. (In practice I use a long steel chisel and knock it out from the inside. This usually takes considerable persistence as the rear bearing is a tight fit in the gearbox case.)

newagetraveller
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Re: Mainshaft removal

Postby newagetraveller » Wed Jul 03, 2019 1:30 pm

The above assumes you have already removed all the springs and plungers and selector forks.

Somewhere in that third motion shaft assembly are a lot of springs and plungers which will fly all over the place if you are not careful.

Main problems are likely to be:
Worn lay shaft and lay shaft bearings
Chipped teeth in first and reverse gears.
Worn third/fourth gear selector fork.

Rust bucket
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Re: Mainshaft removal

Postby Rust bucket » Wed Jul 03, 2019 1:46 pm

I have removed the front cover but cannot get the bearing retaining clip out, sits in a shallow recess. I feel it should have a step in the surrounding casing to pry it out, daft design. I was hoping to tap it out once the mainshaft was out., how did you get your bearing clip out.

newagetraveller
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Re: Mainshaft removal

Postby newagetraveller » Wed Jul 03, 2019 2:16 pm

I used a selection of flat bladed screwdrivers.
I put one in the gap in the split ring to widen it until a space emerges between the ring and the bearing case. I put the blade of a small screwdriver in this space and then work it round until I get to an end of the ring. This enables me to get that end away from the slot, then I move the screwdriver blade back and round until I get the whole ring out.
I hope this makes sense.
It is all rather fiddly.

Rust bucket
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Re: Mainshaft removal

Postby Rust bucket » Wed Jul 03, 2019 3:21 pm

Ok thanks very much, I'll try again tomorrow.


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