gearbox strip down

aaron · **Posted:** Wed Nov 10, 2004 8:05 pm

I need to locate some tools to pull down a couple of gearboxes that i have so that i can rebuild 1 good one from the 2. So i am after a good quality bearing puller to remove the roller bearing on the main shaft, and the longer sockets to remove the 2 nuts holding the main shaft in place. ie the one on the end with the roller bearing and the one on the end holding the diff gear to the main shaft. I have an inkling that there is actually a special tool to get the thing out after i have those nuts off. First time, so it could be a bit of fun. 1st things 1st, get em apart and see what is worth salvaging.

Cheers

Aaron

drmini in aust · **Posted:** Wed Nov 10, 2004 8:20 pm

No puller needed for the mainshaft bearing- it gets pushed back out by a 1/2 round spacer dropped in between 1st gear hub and the bearing. Pics in BMC or Leyland manual.
Tools I use:
long 1-1/2" socket for the mainshaft nut, with breaker bar and 4 ft of pipe.. :shock:

nylon spacer as above,
Circlip pliers for 1st motion shaft circlip
Circlip pliers for outrigger bearing.
Bit tedious to describe how to do it in here- it's all documented in the Mini book of lies.
Lock it in 1st and 4th gears to undo the mainshaft nut. Don't use 2nd and 3rd- you risk busting teeth off the cluster, as a Sprite box owner I know did, a while back.

1st one I stripped took a weekend, I'm down to an hour or so now.

PM me if you need info.

thommo09 · **Posted:** Wed Nov 10, 2004 8:28 pm

sorry to hijack your thread aaron, but it is related,

i just wanted to know how hard it is to rebuild a gearbox, cos i have a couple sitting around and like you i thought i might as well try and make 1 good one out of the two..... now from all you guys in the know, are there any mods/improvements that i should make while i rebuild it? (i'll definately get a centre oil pick-up, but what else....are there better bearings to use etc??) and also I've been told there are some "tricks" that aren't really detailed in the manual (black leyland one) that you need to know to make it a successful rebuild

cheers
-jimmy

aaron · **Posted:** Wed Nov 10, 2004 8:30 pm

I will have to have a look in the book. i may need to go a few tools i feel. i have almost all i need, but a few larger sockets need to be bought i think.

drmini in aust · **Posted:** Wed Nov 10, 2004 8:37 pm

Bearings- not much you can do but replace them. Do them ALL, including the idler bearings and the outrigger.
Layshaft is probably toast- fit a new one and bearings. It's the first thing to wear in most Mini boxes. Some layshafts are better material, they are made here in Oz. Ask around or PM me.
Synchros- they don't make them like they used to, and they are now over $30 each. If they have a .030" approx gap to the dog teeth on the gear, keep them.
Synchro hub springs- take the hubs apart and check them for length. New ones are cheap.
Selector forks- new ones have about .015" side clearance on the gear. If badly worn replace them- don't squeeze them in the vice- a common bodge. They crack easy.
Rod change boxes- strip all the selector levers out, and the pivot bolt, fit a new O-ring under the bolt head.

Yes a centre pickup is a real good idea, unless you drive like a granny! :lol:

thommo09 · **Posted:** Wed Nov 10, 2004 8:50 pm

thanks doc......no doubt you'll be hearing from a bit once exams are over :oops:

mrcooms · **Posted:** Wed Nov 10, 2004 9:05 pm

OK this may sound stupid but if u pull all the gears out how are u meant to know which one is which cos there is a few of em. Do they egrave on them wat they are or something

aaron · **Posted:** Wed Nov 10, 2004 9:13 pm

different teeth counts and different sizes, i think it would be pretty hard to put a forth gear where first is.

Cheers

Aaron

drmini in aust · **Posted:** Wed Nov 10, 2004 9:17 pm

mrcooms wrote:

OK this may sound stupid but if u pull all the gears out how are u meant to know which one is which cos there is a few of em. Do they egrave on them wat they are or something

The biggest gear on the mainshaft (near middle of box) is 1st gear, then 2nd, then 3rd, going towards clutch end. 4th is direct drive (1:1) - the input and output shafts get connected together.
Get somebody to show you, or check out a parts catalog, eg Mini Car Clinic's. :wink:

aaron · **Posted:** Tue Dec 21, 2004 4:59 pm

Ok i have the gearboxes stripped down and have selected the best gears etc etc. I put the selectors and main shaft back in, only to find i can't select 1st or 2nd.... 3rd and 4th no worries. Is there something i am missing. The selector forks are lined up with the holes and tightend so they won't slip on the shaft. Any clues?

Cheers

aaron

drmini in aust · **Posted:** Tue Dec 21, 2004 6:37 pm

Aaron,
Obviously it's a remote box or magic wand, by your description..

Did you pull all the selectors shafts out?

The only interlock in those boxes is the fork plate that sits around the main selector, so it can't really be assembled wrong like a Sprite box can...

.

With the box in neutral, does the diff spin OK?
If a synchro is dragging (new MiniSpares ones are sometimes too thick) it can make it hard to engage the other gears when stopped, or spin the diff in neutral. Nothing that 5 minutes running won't fix. :wink:

If the box is out of the car, I'll have a look if you like.

ozmotorsport · **Posted:** Tue Dec 21, 2004 7:02 pm

Just for the record - DR mini is the master gearboc rebuilder here. He did mine and deans (well tha's mine now too).

aaron · **Posted:** Tue Dec 21, 2004 7:19 pm

Sorry yes it's a remote.
I have only got the main shaft in there at the moment, along with the selectors, i didn't want to continue until i knew that there wasn't going to be an issue with 1st and 2nd. I will clean it all up again, as it has got a little bit of grit into it, as my garage is more like a sand pit.... see if that helps, will keep in contact re a look over the box. But, i am happy to say that the Layshaft is absolutly perfect, not one wearmark on it anywhere. Thanks for the offer doc. Let me try one more time first. Best way to learn as they say is to do it yourself. I have to say though i could d with out learning how to put those little spings and ball bearings back into the ... god i can't think of the name, but i am sure you know what i mean
Cheers

Aaron

drmini in aust · **Posted:** Tue Dec 21, 2004 7:40 pm

Aaron, I have special service tool XYZ for that job, I posted how it works on the MiniPortal website site but somebody has now hacked it.. again! :cry:

Basically it's an old 1st gear outer ring- now `setup ring' ,with 3 chamfers ground inside it where the balls run.
You just sit it under the hub you are assembling, put the springs in, sit the balls there on the 3 ramps, push the hub down and they are in!

No clamps etc needed.
Next part of trick- take the outer ring that goes with this hub, sit in under the setup ring and push the hub down. The balls will slide into your outer ring, no problem!

<edit> note the hub splines are all the same on Minis- 1/2 hub and 3/4 hub, 3 synchro and 4 synchro.

You can now do this job without losing your balls! :lol:

drmini in aust · **Posted:** Wed Dec 22, 2004 6:36 am

OK MiniPortal site is back up so here's the link I spoke about-
http://forum.miniportal.ca/phpBB2/viewtopic.php?t=818
Enjoy! :wink:

gearbox strip down

Who is online