Jump to content
N Dentressangle

1984 Mini gearbox - exciting update

Recommended Posts

Mrs D's Mini has been used as a commuter for 20 odd miles a day in all weathers for the last 6 years, and it's now at the stage where it needs a bit more than just pre MoT fettling.

It's a one owner from new until 2014 car, bought from Wicliffe Rover in Stroud in 1984 by Miss Halford, on her retirement as a primary school teacher. 30 years later she gave up driving, and I bought Silver Susie (as she called it) for Mrs D as a birthday present. She's wanted another ever since she learned to drive in one. TBH I thought she would quickly get sick of the lousy driving position, shit brakes etc and opt for something more modern, but she loves it! Especially as I replaced all the knackered, 30 year old rubber suspension cones early on.

Last year it started jumping out of 2nd on the overrun more and more often, and syncro on 2nd and 3rd was not very special either. There was a rot hole in the rear valance, and the engine was pissing out more oil than it burned, which was quite a feat. It's done about 65k, so long in tooth for the engineering brilliance that is BL! It's always been 'maintained' by one of the local garages, who've committed acts of bodgery I'd be ashamed of, including fitting a s/h Metro van gearbox at some stage. So it's running a stupidly low diff ratio, meaning the speedo is useless and it screams like hell at anything much over 60. I limped it through another MoT by replacing the front balljoints and fettling the brakes a bit, but by the end of last summer I thought we should spare it another wet n salty Cotswold winter and sort it out properly.

The plan is:

  • rebuild / refresh the engine - head job, bottom end inspection and bearings as needed
  • fit stage 1 kit to add a few more beans
  • replace all gaskets and bring the oil leakage down to something normal
  • replace the gearbox and diff
  • clean the engine bay, treat rust and repaint
  • replace the rubber front suspension bushes, engine mounts and all that cheap stuff
  • sort the back end rust out - weld up the valance and any other bits
  • rattle can spray job on the repairs as best I can

There's probably more, but that's all I can think of for now. More later, plus pics of all the action so far!

ps If you know anything about old Minis, I will badly need some expertise. It's not a Land Rover, so I know fuck all about these.

Share this post


Link to post
Share on other sites

Ask away, I have messing with these for 30 years now. I have a load of spares as well if you are short of anything. For the gearbox, buying a second  hand one will always be cheaper short term than a rebuild but it can be hard to tell how many miles are on. Minispares do a decent recon service if you want a good one. Rebuilding one yourself isn’t beyond the average DIYer but like any box, they have a few quirks that can be a pain.

Share this post


Link to post
Share on other sites

A Mini box is pretty easy if you have a Haynes manual and a decent tool kit. I wouldn't really trust a used box at this stage, you're just buying more potential trouble although you could be lucky. A set of gaskets, four baulk rings and the big 3rd motion shaft bearing is a start. Once stripped you may need a layshaft and bearings. The original bearing I mentioned was a ghastly thing with a plastic cage that breaks up. If you can get one, an older pre '80 brass cage A Series (rather than A+) bearing is the one to have.  A+ idler gears and bearings are very tough.

There again, it could have knackered selector forks. You'll know when you split the engine and box.

 

Metro Vans should have an FD compatible with a Mini - 3.64, 3.44, 3.2 or 3.1.

1984 is the change point from 10 to 12 inch wheels. I wonder if it has an Allegro box - now that will be seriously undergeared. The FD on those was about 4.1/4.4 due to 13 inch wheels.

 

The crank and bores should still be good, the 998 A + is a cracking engine really.

 

The problem with Minis now is the amount of aftermarket rubbish that lasts about 5 minutes. If you can find it, original stuff in BL boxes is worth paying extra for.  MiniSpares were always good to deal with however.

Share this post


Link to post
Share on other sites

If you haven't already got one, a pre sworn-at HBOL.

 

https://www.ebay.co.uk/itm/Haynes-Mini-69-to-84-All-Models-Owners-Workshop-Manual/133377066607?hash=item1f0de4866f:g:4D4AAOSw7speElB~

 

You'll need a flywheel puller as well. I think* a 1984 car will have a Verto clutch (slave cylinder on the conical clutch cover, not on the flywheel housing)  but it's a long time since I worked on a Mini. I don't miss it much tbh. 😆

Share this post


Link to post
Share on other sites

OK chaps - thanks for all the ideas!

I started about 2 months ago just going off the HBOL and stripping things off the engine, until by today we were nearly at this stage:

MLYtvx4.jpg

All the bits n bobs pulled off easily enough, and everything was ready for the dirty oily bits to be disconnected, because I knew that this was happening:

aG5VpXM.jpg

Bone cyst removed, bone graft and some other stuff. 6 weeks off legs, which ended just as the lock in crap began. Bollocks.

Anyway, I turned up the engine crane on FB Marketplace for £40 just round the corner - it was as new, having removed one engine. Result!

I also found a very pretty rebuilt box with a 3.11 diff on Ebay for £260:

s-l1600.jpg

so that should be on its way here from Retford at some stage.

Moar shortly

Share this post


Link to post
Share on other sites

Ooh, a Mini 25. Remember those. At least you have the 8.4" discs up front.

 

Put up a link for the gearbox - you don't want to buy it and find it's a pre A Plus box as it won't fit. It has the steel bearing end plate though (only 3 bolts not 4) so it looks about right.

Share this post


Link to post
Share on other sites
3 hours ago, The Mighty Quinn said:

1984 is the change point from 10 to 12 inch wheels. I wonder if it has an Allegro box - now that will be seriously undergeared. The FD on those was about 4.1/4.4 due to 13 inch wheels.

Yes, an Allegro box in a mini would be pretty awful.  Final drive on Allegros:

1100 : 4.11

1300 : 3.94

1000 A+ : 4.33

1300 A+ : 3.76

Share this post


Link to post
Share on other sites

Wow. A Mini25. 

My first car was a 1985 Mayfair which had been my dad's. Only 5 years old at the time. 

(the car, not me). 

 

There was a 25 in the showroom but dad didn't like silver. 

Didn't they rot at an alarming rate even for a mini? 

Mine was scabby around the headlamps and ends of the sills at 5 years old but every 25 I saw was hanging. A panels, bonnet edges door bottoms, scabbing up everywhere. 

 

Miss Haford must have got discount waxoyl from her famous uncles shop. 

Share this post


Link to post
Share on other sites
5 hours ago, N Dentressangle said:

Yep, that's A+ with the DAM casting numbers and no MOWOG to be seen. It's got the big idler gear bearing.

Share this post


Link to post
Share on other sites
35 minutes ago, Timewaster said:

Wow. A Mini25. 

My first car was a 1985 Mayfair which had been my dad's. Only 5 years old at the time. 

(the car, not me). 

 

There was a 25 in the showroom but dad didn't like silver. 

Didn't they rot at an alarming rate even for a mini? 

Mine was scabby around the headlamps and ends of the sills at 5 years old but every 25 I saw was hanging. A panels, bonnet edges door bottoms, scabbing up everywhere. 

 

Miss Haford must have got discount waxoyl from her famous uncles shop. 

Yep, Minis were never rust resistant but the mid 80's onwards ones were shocking. Pissing about with 8000 different limited editions yet no waxoyl or arch liners from the factory.

Share this post


Link to post
Share on other sites

Change the drive shaft oil seals and fit a gearbox rod change oil seal which is like a rubber O ring. 

 

They lurrrrrve to leak from there. As well as everywhere else.

 

Burning oil is possibly valve guides. Especially if smoking on the overrun. 

Changing the valve stem seals can mask the problem for a while but will probably need new valve guides which will need machining and valve seats recutting. 

Share this post


Link to post
Share on other sites

It is possible to mix and match A+/pre A+ engines and boxes, just more of a faff.  You need the correct end plate, idler gear and primary gear to match the choice of gearbox (primary gear also differs between 1275 and the smaller engine sizes).  My Austin 1100 has a 1300 A+ engine on top of its original gearbox (albeit with higher diff fitted).

Share this post


Link to post
Share on other sites

Well, lucky I got the right box then! The guy's prepared to post it - Parcelfarce are only about £15 - as it's under 30kg.

Just hope it doesn't arrive as a smashed up lump of ally, but no real alternatives under the current shitey circs.

Guessworks reckon it would originally have had a 3.1 diff:

http://www.guess-works.com/Tech/engine.htm?P1=99H&LP2P=&P2P=&LP2=&P2=A53&LP2S=&P2S=P&LEN_NO=&EN_NO=0100646

eta Couriers are mostly not interested in gearboxes. Any suggestions / recommendations?

Share this post


Link to post
Share on other sites

Tell them it's an alloy casting. PF don't care.

 

Yes it should be a 3.1 for 12" wheels, 2.95 for 10".

 

Fit an extra oil seal in the selector rod - tap the existing one in about 5mm and fit another one on top. That pretty much eliminates that annoying drip.

Share this post


Link to post
Share on other sites

OK, so next installment.

I don't lying on my back on garage floors anymore, so I'd left all the shitty dirty heavy underneath jobs til last. My 6 year old daughter reminded me the other week though that in her opinion 'I was never going to fix the Mini'. Challenge accepted.

All the suspension joints came apart easily as I'd done them last year for the MoT:

FL3Tmqq.jpg

Even the driveshafts popped out easily with a bolster chisel as a lever. BL special tool my arse.

The bolt in the gearchange housing securing thingy was a PITA, but the worst were the fucking stupid engine mount bolts. They're bolted through the subframe here and here:

Y9hZI8N.jpg

VeUPP8n.jpg

but instead of using captive nuts or fixed studs like any sensible manufacturer, BL use a separate nut and bolt, with fuck all access to the nut or bolt head on the inside. I think they were the only hold up, and pretty soon we were here:

aMuyKfb.jpg

Get in!!! Or out, I suppose. Leaving this lovely gap ready for a Hayabusa engine I swapped with my mate for a brokn X box and some pix of my exs fanny:

kcwybNP.jpg

Not really.

 

Share this post


Link to post
Share on other sites
1 hour ago, The Mighty Quinn said:

Fit an extra oil seal in the selector rod - tap the existing one in about 5mm and fit another one on top. That pretty much eliminates that annoying drip.

You shouldn't really need 2 oil seals. The problem with these is that the rubber bellows which fits over the selector rod and should keep out the dirt and water goes stiff very quickly. When you select second, fourth or reverse gear the rod moves in to the gearbox and squashes the bellows, then when you select first or third the rod moves back out but there is nothing to stretch the bellows back out again. So it stays compressed, the rod is then exposed to all the crap flung up under the car, and the next time the rod goes in the dirt and grit on it wreck the oil seal.

Many moons ago I had numerous minis, 1100s and other A-series front wheel drive stuff which used this rod-change arrangement. I used to have to change these oil seals at least every six months as they would always leak by this time.

I finally hit on the idea of using superglue to fix both ends of the bellows. After degreasing the gearbox casing entry point and the front of the circular coupling that attaches the gearchange rod, superglue one end of the bellows to the casing, squeeze it up and slide the coupling over the rod, fit the front roll pin, then run some superglue around the back of the bellows and glue it to the front of the collar. Then the bellows will be stretched out when the rod moves out and will still protect the whole length of the rod.

After having done this mod on several vehicles, some of which I had for more than five years,  I never had to replace one again in my ownership.

When I bought our current Maxi, which uses the same system, it also predictably had a leaking gear change oil seal so one of the first jobs I did was this, and it is still oil tight after 3 years.
 

Share this post


Link to post
Share on other sites
38 minutes ago, Slowsilver said:

You shouldn't really need 2 oil seals. The problem with these is that the rubber bellows which fits over the selector rod and should keep out the dirt and water goes stiff very quickly. When you select second, fourth or reverse gear the rod moves in to the gearbox and squashes the bellows, then when you select first or third the rod moves back out but there is nothing to stretch the bellows back out again. So it stays compressed, the rod is then exposed to all the crap flung up under the car, and the next time the rod goes in the dirt and grit on it wreck the oil seal.

Many moons ago I had numerous minis, 1100s and other A-series front wheel drive stuff which used this rod-change arrangement. I used to have to change these oil seals at least every six months as they would always leak by this time.

I finally hit on the idea of using superglue to fix both ends of the bellows. After degreasing the gearbox casing entry point and the front of the circular coupling that attaches the gearchange rod, superglue one end of the bellows to the casing, squeeze it up and slide the coupling over the rod, fit the front roll pin, then run some superglue around the back of the bellows and glue it to the front of the collar. Then the bellows will be stretched out when the rod moves out and will still protect the whole length of the rod.

After having done this mod on several vehicles, some of which I had for more than five years,  I never had to replace one again in my ownership.

When I bought our current Maxi, which uses the same system, it also predictably had a leaking gear change oil seal so one of the first jobs I did was this, and it is still oil tight after 3 years.
 

That makes sense - it's like idiots who don't replace the gaiters when replacing shock absorbers. The new one starts to leak in no time.

Share this post


Link to post
Share on other sites
45 minutes ago, N Dentressangle said:

OK, so next installment.

I don't lying on my back on garage floors anymore, so I'd left all the shitty dirty heavy underneath jobs til last. My 6 year old daughter reminded me the other week though that in her opinion 'I was never going to fix the Mini'. Challenge accepted.

All the suspension joints came apart easily as I'd done them last year for the MoT:

FL3Tmqq.jpg

Even the driveshafts popped out easily with a bolster chisel as a lever. BL special tool my arse.

The bolt in the gearchange housing securing thingy was a PITA, but the worst were the fucking stupid engine mount bolts. They're bolted through the subframe here and here:

Y9hZI8N.jpg

VeUPP8n.jpg

but instead of using captive nuts or fixed studs like any sensible manufacturer, BL use a separate nut and bolt, with fuck all access to the nut or bolt head on the inside. I think they were the only hold up, and pretty soon we were here:

aMuyKfb.jpg

Get in!!! Or out, I suppose. Leaving this lovely gap ready for a Hayabusa engine I swapped with my mate for a brokn X box and some pix of my exs fanny:

kcwybNP.jpg

Not really.

 

That's a Verto clutch btw.

Share this post


Link to post
Share on other sites

 

 Hi, The trick with the engine mount nuts and bolts is to weld the nut to the mount flange, you don't need to go mad just a good tack weld to hold it in place until you get the bolt in.

 Colin

Share this post


Link to post
Share on other sites

Ah man I remember doing this a few times when my mini engine shit the bed. I was working on my nans drive, and while carrying the gearbox I walked underneath a hanging basket, banged my head on it and it fell off the hook and emptied the entire contents, soil, plants and gravel into the gearbox. I laugh now but at the time I wasn't so chipper.

I do remember the flywheel was a right sod to get off and when it finally went it nearly send my mate halfway down the drive. Good times. It's been just about long enough since that debacle that I quite fancy a mini again, but unfortunately you can't buy a solid one for £2000 like I did ten years back.

Share this post


Link to post
Share on other sites
14 minutes ago, colnerov said:

 

 Hi, The trick with the engine mount nuts and bolts is to weld the nut to the mount flange, you don't need to go mad just a good tack weld to hold it in place until you get the bolt in.

 Colin

I'll be happy to throw a few quid at a pair of these when it goes back in:

21A1902ST.jpg

http://www.minispares.com/product/Classic/21A1902ST.aspx

Share this post


Link to post
Share on other sites

Right, final update for now.

As you might have noticed, this engine runs the Torrey Canyon a close second in terms of oil tightness. So it's filthy with all the oil that's been puthering out of every seam for the last fuck knows how many years. I made a halfhearted attempt to trace the leaks once, and decided it must be leaking from EVERYWHERE as no bit looked any cleaner or dryer than the other.

Here it is in all its nastiness:

dcQoL7y.jpg

jJGJry0.jpg

8lkWBso.jpg

 

I brought out my biggest guns: a jar of paraffin and a stiff (fnarr) brush, and set to it with the aim of befouling my driveway with as much shite as possible. Plenty of attention all around, followed by half an hour of soaking then a blast with the pressure washer.

Then another brush and a pot of TFR or truckwash stuff, followed by another half hour soak, followed by pressure washer, and finally...

vHEGCXg.jpg

1E4nQ59.jpg

Xq5WHWv.jpg

k95Wo1c.jpg

That's better.

Time to order some bits and start work on the head.

 

Share this post


Link to post
Share on other sites
19 minutes ago, N Dentressangle said:

Right, final update for now.

As you might have noticed, this engine runs the Torrey Canyon a close second in terms of oil tightness. So it's filthy with all the oil that's been puthering out of every seam for the last fuck knows how many years. I made a halfhearted attempt to trace the leaks once, and decided it must be leaking from EVERYWHERE as no bit looked any cleaner or dryer than the other.

Here it is in all its nastiness:

dcQoL7y.jpg

jJGJry0.jpg

8lkWBso.jpg

 

I brought out my biggest guns: a jar of paraffin and a stiff (fnarr) brush, and set to it with the aim of befouling my driveway with as much shite as possible. Plenty of attention all around, followed by half an hour of soaking then a blast with the pressure washer.

Then another brush and a pot of TFR or truckwash stuff, followed by another half hour soak, followed by pressure washer, and finally...

vHEGCXg.jpg

1E4nQ59.jpg

Xq5WHWv.jpg

k95Wo1c.jpg

That's better.

Time to order some bits and start work on the head.

 

That's dry for a Mini engine. Rocker cover gasket and crank end seal will leak the most.

Share this post


Link to post
Share on other sites
5 hours ago, N Dentressangle said:

I'll be happy to throw a few quid at a pair of these when it goes back in:

21A1902ST.jpg

http://www.minispares.com/product/Classic/21A1902ST.aspx

I'd be careful using these. You often need to use a screwdriver or similar to line up the mount hole and the subframe hole. 

If you damage the captive thread or crossthread the bolt in the captive thread then you end up with the spinning captive nut that you cant undo. I've been there. It's fun.

My guess is that is the reason a screw and bolt was used by bl. 

Happy to be corrected there though.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...