21 replies to this topic

[landsurveyor]

Evening Folks.

 

I have an annoying clutch/flywheel problem that I am hoping you can assist me with.

 

My car was MOT'd at the end of October and when I went to collect it from the garage we noticed a slipping clutch in 3rd and 4th gears only.

 

The decision was made to leave the car at the garage for them to fit a new clutch.

 

The car is a 1980 1275gt with a mid 80's A+ metro engine in it.

 

The car had a Verto clutch plate flywheel etc. but a Pre Verto slave cylinder and arm.

 

I made the decision to change the lot to a pre verto setup as I read that they were better for my intended race/hillclimb prep for the engine.  With that in mind I got excited and ordered an MED lightened flywheel assembly like this:  http://www.med-engin...ultra-light-st1

With help from the excellent Guessworks flywheel puller my mechanic (Ed) got the old flywheel off and fitted it.

 

Following installation we can not seem to get the clutch to operate at all.  The clutch will not disengage or work at all when the engine is running, it almost seemd like there is not enough movement in the long arm.  We are getting about 12mm of linear travel in the arm coming out from the slave cylinder - is this enough?

 

We have replaced:

 

Flywheel and clutch assembly.

The seals in the master cylinder.

New slave cylinder and new plunger.

New Mini Spares release bearing and the shaft it sits on.

New Arm.

 

We are tearing our hair out trying to work out the problem and I want my car out (and the nice bloke Ed at the garage wants it out of the way!!).  The only thing we haven't replaced with new is the master cylinder, and I am wondering if this may solve it??

 

Any assistance is very much appreciated.  I am very close to chucking the old clutch back in it and parking it up until I have more time and patience...

 

Thanks very much for any assistance, it really would be appreciated.

 

Simon.

 

 

[cal844]

Have you adjusted the clutch up correctly?

The return stop clearence needs to be set every 3000 miles.

This is checked by inserting a feeler guage between the arm and the bolt half way down the clutch cover. You need to pull the clutch arm away from the bolt(not easy, neither is disconnecting the spring!)

Clearences
0.060 inch for coil spring clutches(early type)
0.020 inch for diaphragm type

HTH

[landsurveyor]

_{Thanks for your swift reply,}

 

_{Yes the mechanic has set the clutch up properly with the 0.020 gap, but it wont go into gear.  With the bolt wound right out (forcing the arm out even further) we could get the clutch to work, on the pedal, but it was then riding the clutch, so we are very confused. I am obviously no mechanic so cant supply exactly how he did it but I have been assisting (at his request!).}

 

_{It is almost like there is not enough movement in the base of the long arm to move the bearing shaft enough to disengage the clutch properly.  Would a new master cylinder help or am I throwing yet more money away?} 

_{The clutch pedal seems to move down slightly less than 1/3 of the way without the slave cylinder moving at all - is this normal??}

 

_{Thanks for any help you can give as I am ready to get my car back and get rid of it (although I don't want to!).  I just don't have the time for this at the moment.}

 

_{Thanks very much!!}

 

_Simon.

[landsurveyor]

Can anyone please tell me what the maximum gap to the small adjustment bolt on the clutch plate should be when the clutch pedal is fully depressed? This is assuming that the starting gap is set correctly. I am trying to work out if we are getting the correct amount of travel in the long arm.

Thanks very much!

Simon.

[Gremlin]

Have you bled the clutch properly, with a 1/3 of the total movement without it moving the slave cylinder it's unlikely it'll disengage properly, I seem to remember you should have about 55mm of travel at the slave cylinder

[landsurveyor]

Yes, it was all bled properly. We have about 12 or 13mm of travel (1/2 inch) which is well short of your suggested 55mm, so I assume that all it can be is the master cylinder, as all the rest of the system is new apart from the pedal itself?

Thanks again for your help.

I will order a new master cylinder tomorrow and let you know how I get on....

Any more ideas on the amount of travel to expect are welcome.

Thanks.

Simon.

[Turbo Nick]

It's a fairly common issue I've seen a few times, no idea what the cause of it is but it can be sorted easily.

 

try dropping a nut or something as a spacer inbetween the plunger in the slave and the push rod, i used a spare manifold nut to troubleshoot mine years ago. Then readjust the plunger locknuts, just make sure the revs don't drop when you clutch in as this will be throwing too far and loading up the crank thrusts.

 

I know another chap who had the same issues so he made a couple of extended slave push rods years ago, one of which he gave to me.

[Mini Manannán]

 

I know another chap who had the same issues so he made a couple of extended slave push rods years ago, one of which he gave to me.

 

Verto or non Nick?  I'm starting to think I need one of those for my verto 

[landsurveyor]

Thats a great help Nick, thanks very much!  We will give it a go and report back...

 

Mine is a Pre Verto clutch.

 

Simon.

[The Matt]

Is your drive-strap alignment correct?

[The Matt]

What happens with lightened flywheels is similar (though exaggerated) to what happens if a flywheel has been refaced:

 

http://www.minispare...rap-alignment-2

[Dan]

Extending the push rod is extreme bodgery and should be a short term fix at best. It doesn't fix the slave travel problem and with only 1/2" travel at the slave you will have a horrible clutch operation. It will either slip or drag and you won't be able to set it up to do neither, it'll be one or the other. I would suggest the problem may be lost travel in the clutch pedal clevis or bushing if it's not the master. Does the pedal rattle up and down without operating the hydraulics?

[The Matt]

Oh god, yeah.  Only just spotted the comment about the 12mm travel!

 

One of mine had a very worn pedal shaft actually, I had the rattly pedal that Dan describes and it was the very last thing I checked after replacing everything else.

[Dan]

I don't think it needs much more than 1/2" travel, but I seem to remember that it's gone beyond hope when it gets that low. I don't think they ever reach 55mm!

[Cooperman]

If you do a search you will find my 'Clutch Drag Fault-Finder' on here. It considers every possible cause for clutch drag/failure to dis-engage.

 

By the way, the top of the clutch arm must move a minimum of 0.50" when the clutch pedal is pushed right down.

Also, has the overthrow stop nut & locknut been set using the correct procedure?