Clutch release problem

[mirabelle]

Hi,

I have a clutch release problem.

I have installed a 1098 engine & gearbox and assembled the clutch linkage to the pedal, but the clutch withdrawal arm is fouling the hole in the casting before releasing the clutch. I've not completed the installation or started the engine up, but it seems pointless to continue if I cannot bring pressure to bear on the clutch. Even so, I've still invested a lot of time and effort to get this far, and thought I would seek help/advice before removing the engine and box again, and at this point, even if I did so, I don't know what I would need to do different to put the fault right. The only theory that I have at the moment, is that there might be a slight bend in the clutch withdrawal arm similar to the problem that used to be encountered on minis where a slight bend in the release arm caused lost movement and an inablility to disengage the clutch.

Any help or advice would be appreciated.

Andrew

[bmcecosse]

Hmm - have you looked up through the inspection ports in the bell housing to see what's going on ? Is the carbon thrust 'unworn' - and is it touching the release plate on the clutch ? Are you sure you have a saloon 1098 clutch/flywheel in there - and not a Spridget clutch/flywheel - which is designed to work with a hydraulic release? I'm well familiar with the Mini clutch arm problem - but have not heard of it on a Minor.

[Axolotl]

Is it possible you asembled the release arm that holds the graphite bearing "back to front" on the bearing?

I don't know if that is physically possible, but it would put the release arm well off centre of the hole in the bell housing, judging from the drawings in the workshop manual.

The release arm "C" cups that the graphite bearing pivots in should be on the side away from the clutch, pushing the bearing towards the clutch.

Just a thought.

[rayofleamington]

A very long shot - you are pulling the release lever towards the back of the car? If so - then read on. (if not - try it the other way ;-))

Unfortunately you'll have to get the engine or gearbox out again
Once out, if the problem is not obvious then post some pics and we'll probably be able to see what's what. Most likely is wrong parts or miss-assembly. The clutch arm isn't going to bend - but are you sure it's the right one? (There are a few variants of arm etc..)
It might also be useful to know which parts have been replaced during the process - and were you sure everything was working ok before it was taken apart?

The 1098 clutch is deeper than the 948 - so the release bearing variant is shallower. If you have the right depth of clutch cover you can't get this problem from a 'wrong release bearing'.
However if the cover is only as deep as the 948 clutch, you WILL get this problem when using a 1098 release bearing.
I'd be surprised if that is the problem but it's anyone's guess at this stage.

Hindsight can be very annoying... Having had problems myself reassembling engines or transmissions I always (nearly always) check that stuff works before bolting it all back up.
e.g. that an engine will turn over stage by stage during the rebuild, ot that all gears can be seleceted on a gearbox before putting it back in the car... or that the clutch lever has some slack but reaches the clutch before at least half travel (you will loose some travel if the gearbox isn't bolted to the engine, but it's worth to check before spending the time fitting the bolts.)

[bmcecosse]

From Ray's words above - is there a chance the engine has a 948 flywheel and clutch fitted - and you are mating that with a 1098 gearbox ? Whatever it is - no need to take the gearbox back out, just pop the engine out once you dcide what has gone wrong.

[rayofleamington]

You can take out the engine, or the gearbox or both at he same time depending on what equipment you have to do this.
Personally I don't bother taking out the engine as it's much heavier than the gearbox and I've not installed a hoist - gearboxes don't need lifting equipment and won't break your leg if it falls over.

[bmcecosse]

We chatter away - but 'mirabelle' seems to have disappeared!

[simmitc]

One thing I love about this board is how we can all have very different opinions about the same thing. I'd always take the engine out rather than the gearbox (I have a hoist) as there's less to undo - don't have to disturb the clutch linkage or all those screws in the gerabox cover, or the prop shaft. To drop the box you still have to allow the egnine to tilt and so do have to disconnect exhaust, steady bar, hoses, etc. Also, if you need to chnage the clutch or flywheel then it's easier with the engine out.

Anyway, backj to the original problem, you still have to take one or the other out to find out what's wrong. I have seen the clutch release arm in back to front with exactly these symptoms as the retaining clips stretched under load.

[bmcecosse]

Engine for me too - hate lying under a car - dangerous!! Engine comes out easily enough - even without a hoist - but look in Barry's site ( http://www.badfelafel.co.uk/) in the workshop section - changing the engine - to see me and my portable hoist in action!

[bmcecosse]

Just a thought - IF the fork is in wrong way round - would it be possible in any way to get the release bearing off the fork - and then reverse the fork without taking the engine or box out ? Would mean working through the inspection holes (or make a bigger hole with a 3" hole saw!) - but would save a terrible amount of work if it could be done!

[IaininTenbury]

MY gut feeling is that its a mismatch of components and there's some 948cc bits in there. I had this problem years ago when I first fitted a midget engine with 948 type clutch. I ended up heating the release arm and bending it a bit more... Not the nicest fix but it worked ever since and I never really found out why it didnt work first time round.
Of course it does need to come apart again. i normally do a dry run on the floor, bolting the engien to the box and seeing if its all ok, (hindsights great isnt it) but odd that the prob should occur with a standard 1098 setup.
Do let us all know what it was when you find out!

[mirabelle]

Hi all,

Thanks for your suggestions.

The good news is - I now have what appears to be a functional clutch, although I won't know for certain until I get the car back on the road. I'd like to give you a definitive answer as to what was wrong, but the results have been a little inconclusive.

I'm in the process of totally rebuilding a late convertible using a fully restored rolling shell, utilising all the bits and pieces I've accumulated over the years, so I've not had the benefit of seeing any of the componentry running.

I was using a new release bearing, a new old stock driven plate, and a cover/pressure plate (Borg & Beck) that had done 6000 miles in a previous vehicle in an effort to save a little bit of money as I've already spent a fortune on the paint etc. I measured the thickness of the flywheel which was the same as another 10MA prefix engine, I compared half a dozen release arms which were all pretty much identical, and compared the release bearing with others I'd got in stock - again this appeared to be right.

When I put the engine & gearbox back in I used the same bearing, a different release arm, (although there didn't seem to be a problem with the original) and the same pressure plate as before. However, the friction plate did seem different to another NOS plate I'd got in stock so I tried a different plate. I took the precaution of assembling the box to the engine and checking the release arm prior to putting back in the car, and on this occasion the arm was not fouling the edge of the window in the gearbox casing. Once linked up, everything appeared to be in order.

Conclusions:
the release arms do not appear to bend as I thought they might;
the driven plate, although Borg & Beck 7 1/4 inch and same splines appeared to be the cause of the problem, although it did appear to be similar to others that I had in stock.

The only thing I can suggest after all this is that assembling the clutch, box and engine and testing the travel of the release arm prior to fitting into the car is the only certain way of avoiding a world of grief.

I realise that all the foregoing does not add to the sum total of human knowledge, but it might help in some small way.

Thanks again, Andrew