gearbox rebuild

[Budgie]

Right as a very big novice to this subject I, together with my brother-in-law[ he's the brains in this department and I'm on a rather big learning curve] are thinking of rebuilding my gearbox as the reconditioned ones I've seen around tend to be rather on the pricey side! So my query is , seeing as it's only current issue is crunching on third gear, and assuming it's the synchromesh, is the aforementioned attached to the third gear?

[Trickydicky]

I remember a detailed rebuild from Biomed32uk on a 1098 box last year. It looks like it is still available.
https://dl.dropboxusercontent.com/u/509 ... ebuild.pdf

[les]

The above link is just the job if you need guidance. You are right about recon boxes being expensive and you can never be sure of the care the rebuilder took, not to mention knowing what has or has not been replaced.

[Lurch]

That link is a great tutorial, and raises a number of issues that are just wrong or misleading in the likes of Haynes etc, includes much good Intel, highly recommend

[Mark Wilson]

I'm just finishing mine, using Biomed's superb guide. Definitely don't rely on Haynes when removing the first motion shaft if you've got a ribcase! Mine's a Midget 1275 and there are quite a few crucial differences, which I'll write up when I get time. Go for it, though, it's challenging but rewarding (well, won't be able to test mine for a few months and won't be so rewarding if it don't work!)

Mark

[biomed32uk]

Glad the guide is coming in handy, the only bit I must add in is assembling 1st gear onto the hub, which is easy. My box has done 2000 miles since rebuild and is all fine still.

Theres nothing to be scared of in the gearbox as long as you take time and work methodically.

Not sure if there is somewhere here the guide can be posted for download.

[Trickydicky]

Glad the guide is coming in handy, the only bit I must add in is assembling 1st gear onto the hub, which is easy. My box has done 2000 miles since rebuild and is all fine still.

Theres nothing to be scared of in the gearbox as long as you take time and work methodically.

Not sure if there is somewhere here the guide can be posted for download.

I think it's one important upgrade that's been overlooked, a section where documents and how to guides can be uploaded and be available to download by forum members.

[Budgie]

I agree that the link for doing a gearbox rebuild is very informative and it would be good if we could download it and print off for future reference. So is there anyone out there that can answer my question in relation to this thread, although I think from reading the link to gearbox rebuild that it is attached the third gear but clarification would be grateful.

[biomed32uk]

I assume its crunching when changing into 3rd ?, if so yes more than likely the synchro ring has worn. It's one of those things that when you go the effort of stripping it down it's time to carefully assess everything and if worn replace it while you are there.

The dog teeth may have also worn on 3rd but thats more likely to cause it to jump out of gear.

If the rest of the gears select fine, and the box is quiet in operation then it may just be a ring and no more. The layshaft is well worth checking though, as that takes a hammering.

Don't be scared of stripping it down, sandwich bags for the bits, labels, a camera and work methodically.

[les]

The 3rd gear has a cone as part of it, one of the baulk rings fit over the cone end.

[Budgie]

Thanks for that bio and yeh it's crunching when going through third both up and down the box either wise she is quite and smooth....well apart from it very occasionally jumping out of 1st and 2nd but that hasn't happened for a while now .

[biomed32uk]

That does sound like a worn synchro ring on 3rd then. Jumping out of gear can be for many reasons, wear in the actual gear assembly's, or wear / something loose in the selection mechanism. I am making assumptions its a rib cased box - 1098 ?.

It's a total strip down to get at 3rd gear anyway and if the rest of the box is good it really is money well spent on a proper overhaul. If anything else is wearing it won't get better, and ultimately it will terminally wreck what is a decent gearbox for the sake of a few new parts.

Check the bearings on the 1st and 3rd motion shafts, the needle bearing on the nose of 3rd motion shaft, the synchro rings, dog teeth on the gears themselves, the bronze interlock washer between 2nd and 3rd which is known to break up, layshaft and bearings in the laygear.

Everything else just needs the usual clean and inspect.

[Sleeper]

While we're at it my box ( ribbed ) is half way out,is noisy in first...befor I delve into it any guesses/pointers?

John

P.S. I thought Colin Chapman was a bit of a prat but Messers Issigonis and Haynes have just joined them...no matter how much I rotate the box it won't come out...engine out seems the only way....and why put big nuts/bolts just below the gearbox cross-member when this has to be removed downwards???

[les]

You don't need to remove the engine. Tilt it backwards. You should be careful who you call a prat

[biomed32uk]

Watch the heater tap when dropping the engine down, in fact you gain some more by removing it and stops you snapping it off.

I have never removed the box this way yet, the engine was out when I did mine so it was easy to remove the rear mounts and up and out through the engine bay.

The crossmember should be easy to remove, remember there are some screws inside the car as well that hold it. The interesting ones are the those into the chassis legs, mine has nuts inside the legs which has been done in the past. Its on my job list to make a couple of plates up, drill and tap them. Then make it captive in the leg so I can unscrew the crossmember without taking the cover out.

[Budgie]

Thanks again for the reply biomed and yeh it's 1098 ribbed gear box .My intention is to strip it down while its out, engine also, and replace where necessary[ I think generally the box is in pretty good condition] with heavy reliance on my brother-in-law whom has only recently totally restored two Nuffield 342 tractors to include body work engine and gearbox and all on his tod fair play!

[surfergirl]

"Issigonis a prat" Working on the Morris is a joy compared to other cars, the guy was a genius.

[Budgie]

Well the engine and gearbox are out and the gearbox is in bits on the bench! So far all looks well with just the third gear synchromesh requiring replacement and even then it looks ok but for a slight bit of wear which my brother-in-law who's the brains and brawn behind this rebuild, says is the reason for it "crunching" through third each time. I will be changing various bearings, bushes and the odd baulk ring just to be on the safe side and seeing as it's in bits and I don't want to go through this escapade again in a hurry! I will also be fitting the "gearbox front cover with oil seal modification". And I would like to change the 3rd / 4th gear selector fork but I can't seem to purchase one as they are out of stock in all the usual places!

[biomed32uk]

Good work, well done. I found the gearbox an interesting job to do, quite rewarding and quite fascinating just to look at the gears moving when its all together, even my wife who has no interest in such things said so !.

As for parts I have used this guy before, some say he is expensive but for what I bought from him I didnt think so, and he does know what he is doing as he has written some articles on the gearboxes as well.

http://www.mirabelleclassiccars.co.uk/gearbox.html

[Budgie]

Wow! I wish I had had those gearbox supplier details before I ordered from ESM as the third gear set up was £72.00 in ESM and only £15.00 with the link that you've supplied plus he has a 3rd selector fork which I will be following up on. I could have halved my order bill if I had seen this before Saturday .But thanks for the link / info anyway at least if others are gonna be doing the same in the future then this guy is a must to check out first off.