Replacing the clutch - a home job

Post by **corgasket** » Sat Feb 11, 2006 5:12 pm

I have 2, 3 ton axle stands and 2 heavy duty ramps and I am (planning) on attempting clutch replacement on a 948cc whilst the engine is in the car.

Does anyone advise me not to do this for access or safety reasons?

Also, does anyone know how to center the clutch pad? The Haynes manual says that it is relativly easy - but I doubt this!

Appreciated.

Post by **bigginger** » Sat Feb 11, 2006 5:22 pm

Useing a clutch centreing tool or a sawn off old 'box input shaft is the easiest way - don't bother with the toy tool from Halfords, Machine Mart and places keep good ones.

Post by **corgasket** » Sat Feb 11, 2006 5:39 pm

Thanks Andrew, When I first got the Minor six years ago there was an old rusty piece of rod with teeth edges running along, which I have since chucked... I am now presuming that this was/is the 'box input shaft' that you refer to. I have a lathe at work available to me, and I am (now) planning on fashioning a rod with varied diameters to help with the centering.

is the gearbox a bind to remove underneath a car on 'stilts' (axle stands)?

Post by **bigginger** » Sat Feb 11, 2006 5:51 pm

I've only ever used the 'engine and box out' method. I've put a box back in (once!) and have to say it's quite a bit harder

The tool I have uses various pieces that look like sockets and screw onto the rod to locate the shaft into different sized holes at the crank end, and a conical piece which slides on the rod to centre the plate.

Post by **Packedup** » Sat Feb 11, 2006 5:52 pm

Not tried taking a box off with the engine still in, but I agree on the use of an old input shaft.

When fitting the pickup clutch plate we butchered a knackered old box and took the input shaft out complete, made lining up the new bits an utter doddle

Post by **corgasket** » Sat Feb 11, 2006 6:07 pm

I feel a right idiot for throwing the shaft away! However, I do have a spare engine and gearbox in the garage that I took apart this morning to have a look and attempt re-assembly and the gearbox will naturally have the shaft running through. As far as I know the gearbox is in fair condition and I would hate to find myself unable to replace all the gears and assemble the box afterwards.

I aim to learn and get satisfaction from this job and save about £200 labour.

Post by **bigginger** » Sat Feb 11, 2006 6:14 pm

I seem to remember that Ray is a fan of the 'drop the box' way of doing the job - if so, I sure he can advise,

Post by **corgasket** » Sat Feb 11, 2006 6:22 pm

Is this Ray Newell we are talking about? Is engine extraction and replacement a fun thing to do? Or is it fraught with lining up and balancing jobs? I can borrow the mini crane and chain from an old work friend. looking at the spare engine I have in the garage the A series is so small and fairly light. looks like my C90cub is going to be used to commute throughout our blizzard winter... Will the cold weather ever arrive? Don't tempt it!

Post by **bigginger** » Sat Feb 11, 2006 6:37 pm

No, rayofleamington to give him his 'full name'

A board regular. Engine extraction and replacement is pretty simple if you have a crane, just a question of being certain that everything is unattatched to take it out, and being sure it's all back on again when it goe back in. The easiest thing to miss going in or coming out is the steady cable and earth strap at the back of the 'box - or is that just me?

Post by **minor_hickup** » Sat Feb 11, 2006 7:31 pm

Theres some info on this site http://www.mmoc.org.uk/technicaltips/clutch.pdf, that might be of use

Post by **Alec** » Sat Feb 11, 2006 7:33 pm

Hello Corgasket,

as you have a split engine\gearbox, a centring tool will be easy to fabricate. Basically a stepped diameter shaft, make the end to the dimensions of the extreme end of the input shaft and follow with a larger diameter equal to the root diameter of the splined section. This should fit closely into the clutch centre plate. You just need a handle some 6" beyond that. The diameter does not matter and can be the second one if you like. Much harder to explain clearly than do, but all you do is place the centreplate onto the tool, and insert it into the end of the crankshaft. Then place the cover plate in position and bolt up. Just ensure that the tool and centre plate does not droop as you tighten up the clutch.

Alec

Post by **HarryMango** » Sat Feb 11, 2006 7:46 pm

I have changed 2 clutches by "drop box" method with no real problems - the only tricky bit I found was the weight of the box when you are refitting it lying under the car, so get the car as high as you safely can for more working room.

As to clutch alignment I make up my own tool with 10" socket extension bar fitted with suitable socket and a large repair washer slipped over the shaft to line up with the clutch cover & its a doddle.

Rog

Post by **rayofleamington** » Sat Feb 11, 2006 8:08 pm

As to clutch alignment I make up my own tool with 10" socket extension bar fitted with suitable socket and a large repair washer slipped over the shaft to line up with the clutch cover & its a doddle.

I just use one end of a wooden valve grinding stick and wrapped some tape around it part way down to make a snug fit for the clutch disk. It's worked fine for nearly a dozen clutches so far.

People get very stressed about centring the clutch disk, but it is only an initial assembly aid. Once the gearbox is on, and the clutch pedal pressed the disk is free again and finds its own centre on the gearbox input shaft.

I prefer to use the gearbox out method to do change a clutch as I don't have a hoist therefore engine out is not something to tackle solo.
Gearbox out is not so hard - putting it back is a real pain unless you're used to it.

Post by **bigginger** » Sat Feb 11, 2006 8:16 pm

Just like the engine and box together method, then

I don't have a hoist any more, thanks to the lovable rogues, so I'd better prepare myself for the next time I have to do it...

Post by **Willie** » Sat Feb 11, 2006 9:34 pm

I too have changed the clutch with engine in situ but it requires a bit of
strength when juggling with the box under the car especially when the tail
shaft gets wedged up your left nostril! Since you have to undo lots of engine
fittings ,such as the front engine mounts, to enable it to be lifted up at the front so that the gearbox can withdraw without fouling the steering rack, it
is much easier to remove engine/ gearbox as one unit. I have fitted an
ordinary scaffold pole across my garage for that purpose and that has taken
the much heavier weight of an MGB engine with no problems. I use the end
of a wooden valve grinding tool for the centreing like RAY.

Post by **bmcecosse** » Sun Feb 12, 2006 10:55 am

The box is bluddy heavy and awkward when struggling under the car like that. A pit would help. I prefer to take the engine out - just the engine, leave the box behind. I take the head off to reduce weight - and then I can wriggle it out myself with a trolley jack under the sump and another under the gbox. Valve tool makes a good centering tool - if you have a lathe make a tool from a piece of brush shaft! You can get the sizes from your spare gearbox without dismantling.

Post by **ericwork** » Mon Feb 13, 2006 10:45 am

well I have just changed a gearbox this weekend for my daughter, her gearbox was getting very noisy and I had a spare few hours. I remember reading recently somewhere on this board that fitting a gearbox was much easier without the stearing rack in place (it may well have been Ray with his left hand drive conversion). So I undid the two clamps that hold the rack to the body but left the pinch bolt at the bottom of the column in place. This made the job heaps easier as there was quite a bit of free movement in the rack for it to be pushed out of the way. I did disconect the exhaust and engine steady and jack it up at the front slightly, (to angle the back down slighly). Much much easier. As for clutch alignment, which of course I didn't need to do this time, I have always just done it by eye and as Ray said the first time you push the clutch down it all sorts itself out.
Hope this helps.

Eric

Post by **Kevin** » Mon Feb 13, 2006 2:02 pm

If you are going to all this effort dont forget to change the input shaft bush in the flywheel as they are only a couple of quid and keep the gearbox alignment, if its been there a long time it will be well worn and can give gear selection problems.