Lightweight gearbox problem

[Steve S]

Tried 200 plus degrees and still no joy, although the main bearing fell out!

Have a friend who works on very large engines coming round to look at it, talking about impact drivers...

Steve S.

[Ozmadman]

It's quite a long tube with a very fine thread, lots to get stuck!

[Steve S]

My friend hasn't yet looked at the seized plunger bolt. However I have been attempting to get the nut off the mainshaft so that I can replace the ball bearing race.

I'm assuming it's not a left hand thread but cannot get it to shift despite clamping the mainshaft in wooden blocks in a vice and a workmate. Have soaked it ad nauseam but haven't tried any heat yet.

Any suggestions?

Steve S.

[Janet]

I'm assuming it's not a left hand thread

There's only one left hand thread on a lightweight and it's where the gearbox drive sprocket fits on.

[Ozmadman]

My friend hasn't yet looked at the seized plunger bolt. However I have been attempting to get the nut off the mainshaft so that I can replace the ball bearing race.

I'm assuming it's not a left hand thread but cannot get it to shift despite clamping the mainshaft in wooden blocks in a vice and a workmate. Have soaked it ad nauseam but haven't tried any heat yet.

Any suggestions?

Steve S.

Normally they undo on their own causing the bearing to wreck the casing!!! previous owner must have glued it on!!

[Steve S]

Ok so apply heat with a torch right on the nut and it should free it?

Steve S.

[Steve S]

The mainshaft nut just wouldn't budge despite repeated torching. The camplate spring holder remained just as obstinate, defying repeated oven warm ups and even using a freezer spray in the internal cavity.

Then just as I was considering approaching a garage (!) my friend breezed round with his electric impact driver and had both items off in less than 15 seconds! Must get one. He was very modest though, saying the heating and cooling had probably freed it.

Just one issue now I think, how to ease the tight new layshaft bush, wet and dry or a hand reamer?

Steve S.

[Ozmadman]

Just one issue now I think, how to ease the tight new layshaft bush, wet and dry or a hand reamer?
Steve S.

Don't remember mine needing easing?? often it is said that wet/dry can leave abrasive in the bronze but I wet/dried my sliding (output gear) bushes a tad and they have been fine. A very fine small cylindrical sanding thingy on a Dremel will probably do it with a bit of solvol for polishing

[bob0121]

A good one like that comes in at around £350 ish. Worth their weight in gold if you have enough need for one.

[Steve S]

Thanks guys, I've eased the bush off with wet and dry but suspect that when I press it into the housing it will be tight again as it is a very close fit.

New problem is the sliding third gear which I bought (new) but doesn't slide on all the way and no amount of filing at the critical point is easing it; I guess it is hardened and therefore resistant to filing?

Steve S.