mk1-forum.net

driving home the other day and cogged my mini down into third, only to be met with a nasty noise and a neutural.......


it would go into third with care, but made a 'interesting' noise - i figured from what it was doing (driving, but making a ratteling noise), that the roller bearing under third had collapsed (very unusual eh?), so, carried on driving it, trying to avoid having to use third at all.

got home (80 miles) and tugged the motor yesterday.....


sure enough, collapsed mainshaft bearing and a very chewed up third and laygear.....





i have never seen a box suffer from this failiure before, out of the hundreds and hundreds that ive stripped over the years - ive done a thousand miles or so in this box, and up until the moment it failed it had never made a noise, baulked a change, nothing - very odd!

Was this in a late box?
My daughters Sportpack did this last year, exactly the same. I'd never seen that before and I spoke to Jim Brindle, he had the same thing in, the week before on a customers car. He had never seen this before either, up to this point.

Bad batch of cogs from rover? We had a idea that it might had cracked at some point and then et go later on in its life.

its an a plus box, but an old one, they are the double groove a plus teeth.

this has started due to the mainshaft bearing going and letting the gear cockle over though - the damage to the teeth is a result of this.

its very strange, im gonna strip it tonight, so will see what else i find

Post it up here when you do.

I was going to give you a bell about my technical post (today) to get your view.

BUPA or BHSF
Sorry Rich That looks expensive though.
G

contour51 wrote: BUPA or BHSF
Sorry Rich That looks expensive though.
G

nah, a new gasket set and some secondhand shizz and it will be up and running again, im going to refresh the motor as well, so its on a super tight economy budget - the annoying thing is it treated it to a new carpet last week, and this is how it repays me.....

Wonder what the pump sucked up

36inter wrote:Wonder what the pump sucked up

im not thinking about that yet....

ive pulled a big and a main of the motor, and they look box fresh, i just slung the pump....


the box is stripped and cleaned....


anyone fancy a third gear jigsaw........






the side loading has broken the collar that seperates 2nd and third thats part of the mainshaft!

despite all this abuse the baulk ring is in one piece (please note - one particular member of this forum - exactly how rough do you need to be to actually break the baulk..... )

ouch!!

You'll need a good orthodontist to sort out that

Had a similar issue when I had my GTM, pulled away from the lights...nothing then some drive & a load of gear noise, then nothing, then enough drive to get off the road & that was it! Only two teeth left on the pinion gear

As with yours, no prior warning etc. The pump was screwed but the filter collected the rest of the bits & the rest of the motor was fine.

Does anyone still produce the brass caged bearings?????

Mike.

guru_1071 wrote:
despite all this abuse the baulk ring is in one piece (please note - one particular member of this forum - exactly how rough do you need to be to actually break the baulk..... )

It's a special skill reserved for only the most tallented of gear shifters.

Sorry to see your gearbox in such a state

was it the big center bearing that collapsed ? (nylon seperator)

I had this in 2 gearboxes, both A+ .

I belive its the remains from burnt fuel in the oil, that make the nylon go brittle ?

good to hear your engine didnt suffer

If you want to stick with the wide ratio 2 groove setup, I have a spare set of gears of that type available.
Nick

JC T ONE wrote:Sorry to see your gearbox in such a state

was it the big center bearing that collapsed ? (nylon seperator)

I had this in 2 gearboxes, both A+ .

I belive its the remains from burnt fuel in the oil, that make the nylon go brittle ?

good to hear your engine didnt suffer

no, it was the nylon caged bearing under third gear.

you may have a point about the oil affecting the nylon, the car had been stood for many years - however all the other bearings are ok - ive just tried to snap the bearing under second and the nylon is ok.

guru_1071 wrote:

no, it was the nylon caged bearing under third gear.

you may have a point about the oil affecting the nylon, the car had been stood for many years - however all the other bearings are ok - ive just tried to snap the bearing under second and the nylon is ok.

Ahh OK, the A+ box I have in the Black one, had a partly collapsed seperator in the main bearing.
I checked the others, and they all seemed fine (soft) so I didnt change those, hope nothing happens

I spoke to an technical engeneer about this, and he agreed to the old oil, with burned fuel remains, could be the cause of this
But I also remember that all early Metro,s had the main bearing changed, before they had done 62000 miles, it seemed like they broke around 55000 miles, so maybe its to do with the manufacturer ? there could have been different suppliers ? who knows