gearbox rebuild advice

[cab43]

Hi all,
I have recently purchased a gearbox and I initially thought it was seized solid, as it wouldnt turn by hand.
as it turns out it was in 2 gears locking it up.
It actually looks like a pretty good box with no wear or broken teeth, the only damage seems to be water damage on the input bearings from being stood on its bell housing outside.

Anyway, I'm going to have a go at fitting new front and rear bearings and generally de gunking it, only problem is I haven't got a clue how to remove the internals, I've removed the extension, selector rods, and the rear bearing circlip now I'm scratching my head as to what next.

Can anybody point me in the right direction for an idiots guide or have the time and patience to explain.

Thanks.

Paul.

[panky]

Have a butchers at this.

http://www.mmoc.org.uk/viewtopic.php?f=4&t=58486

Pretty much the definitive guide and there's a PDF with all the strip down stages, with pics, second page from the end, brilliant

[cab43]

Have a butchers at this.

http://www.mmoc.org.uk/viewtopic.php?f=4&t=58486

Pretty much the definitive guide and there's a PDF with all the strip down stages, with pics, second page from the end, brilliant

Wow!!
thanks panky and thanks biomed that is absolutely bloody perfect!

I hope it's quiet at work tonight, so I can have a proper read.

Thanks again.

Paul.

[biomed32uk]

Be interested to know how you get on with it. There are a few bits that I want to alter with it, and I want to put in how to reassemble the 1st / 2nd hub, with the springs and balls. If there is no need to take it apart don't, for what you need to do you won't.

I only had the brain wave about doing it once I stripped the box, but pretty much read the guide backwards.

Roughly this is the process and isn't hard, after giving the exterior a good clean.

Take the covers off, take the tail extension off, remove the forks and rods (watch all the springs, balls and slugs, withdraw the output shaft assy (I held the box by the tailshaft and tapped the casing downwards carefully to free it, just off the floor over a nice soft sheet), take the layshaft out, remove the clip from the input bearing and drift the assemly out by tapping it into the box, remove the laygear

A noisy input bearing was my reason for doing the job, a full rebuild and several new parts and my box works a treat. Good luck with it, dont be scared of it, its really not that complicated, just take your time.

[cab43]

Hi Biomed,
unfortunately the decision about the 1st/2nd hub has been made for me, whilst fiddling I slipped it too far back and got hit in the eye with a spring.
but I was looking around online yesterday and found a video explaining how to reassemble and it looks really simple, it employed a cable tie and being flexible you Could place each ball and spring and then slip the cable tie over them, then tap the outer gear down.
I'll see if I can find the video and post a link.

thanks for the how to, gearboxes have always been witchcraft as far as I've been concerned, I was using an old autodata book witch isn't much cop really
.

Anyway I'm off out to the shed to see if I can ping some more springs around, I'll let you know how I get on.

Thanks.

Paul.

[biomed32uk]

Thats the one, that cable tie method works an absolute treat, thats the way I did it and its really easy. Just watch for the location of the outer ring to the hub, there is a relieved tooth inside the ring that has to line up with the slug in the hub.

You'll be fine, a decent bearing puller is useful for getting the bearings off but inginuity always works.

Good luck, sure it will go well.

[cab43]

So am I right, in your last post you just lift up by the output shaft and tap the housing down to remove it?

[bmcecosse]

Yes - that works fine. Worth noting that any box that has been stored standing on the bell will need a new front bearing - all the little bits of rubbish run down into the bearing..... If lucky - it may be possible to clean them all out, as long as the box hasn't been run in the interval.

[cab43]

Thanks bmcecosse,
yes the front bearings are pretty ropey, looks like the oil has seeped away over time and been replaced by water, although it looks like the water has reached 4th gear i think the damage is superficial, but I'll be changing all the bearings.

Update!

Managed to get it all apart and, I think it doesn't look to bad, the rear bearing carrier didn't give up without a fight fight but I won in the end with no casualties.

I've posted a couple of pictures of the shafts would love some thoughts on their condition, you can guarantee I've missed something.

[cab43]

Gearbox internals[frame][/frame]

[cab43]

Don't know why the picture won't upload, I'll try later.

[panky]

The picture files might be too big, try reducing them to 640 x 480

[cab43]

Reverse[frame][/frame]

[cab43]

Complete with moss[frame][/frame]

[cab43]

Input bearing[frame][/frame]

[cab43]

The picture files might be too big, try reducing them to 640 x 480

Cheers panky.
gave them a quick trim and all was good

[biomed32uk]

From those photos it dosen't look too bad, sludgy mess of oil and water, as long as it is just surface rust and staining then it should clean up OK, as long as there are no pits in the teeth. The front bearing as you say has had it.

1st gear looks like its had a charmed life, has this box been used or rebuilt and left standing.

What's the layshaft like ?, as that normally picks up on the thrust side of the bearings.

The dog teeth on 2nd and 3rd gear can wear, as can the nibs on the synchro rings. Also worth inspecting the bronze interlock washer that sits between 2nd and 3rd gear when you strip the shaft.

I would give it all a good clean up and see what it looks like after that. A small brass brush is ideal for cleaning the gears.

[cab43]

From those photos it dosen't look too bad, sludgy mess of oil and water, as long as it is just surface rust and staining then it should clean up OK, as long as there are no pits in the teeth. The front bearing as you say has had it.

1st gear looks like its had a charmed life, has this box been used or rebuilt and left standing.

What's the layshaft like ?, as that normally picks up on the thrust side of the bearings.

The dog teeth on 2nd and 3rd gear can wear, as can the nibs on the synchro rings. Also worth inspecting the bronze interlock washer that sits between 2nd and 3rd gear when you strip the shaft.

I would give it all a good clean up and see what it looks like after that. A small brass brush is ideal for cleaning the gears.

I haven't been back to it yet this week, been mobbed at work but I think the layshaft is unblemished.
It has the remains of gold paint on the case so I'm guessing it's been rebuilt at some time, not sure if it was used or not, there is a little bit of damage to the lay gear on a few of the teeth from rust but not sure if it's terminal, I'll post another picture, probably on Monday when I order the bearings etc from bull motif.
I enjoyed stripping it down so much I've just bought another one To rebuild...well you got to have a hobby

[biomed32uk]

Works is always an issue getting in the way of our interests, unfortunately it helps pay for it.

It would seem its had something done to it sometime in the past then being gold, 1st gear just looks very not chewed up.

If it's just surface rust and staining then it will be OK with a good clean, if the rust has actually pitted the surface then that's damaging the hardening on the teeth, then a call has to be made on whether to re use or replace. That may depend on what the cars purpose is, daily drive or a sunny Sunday and how bad the pitting is.

I found rebuilding the gearbox very interesting and satisfying, even just rotating the finished box looking into the side cover, quite a work of art. Even my Wife found that interesting to look at

Sure it will come good, I am on the look for another box to sort out and put in stock as well, sure an opportune one will show up near me sometime. I enjoy working on the car as much as driving it, all part of the fun.

[cab43]

Oh definately, working on it is half the fun.
I try to use it as much I can, but not long journeys, it just makes a nice change from my very comfortable but sterile ever day car.
I'm trying to get all the little bits and pieces done before the 14th of June for the classic run in Coventry and a smooth as silk gearbox would be the cherry on the cake.
so fingers crossed for a quiet week at work