mk1-forum.net

Please can anyone advise me why after fitting a new clutch in my MK2 I can shift the gear stick and select all gears when the engine isn't running but when the engine is running I can't put the car into any of the gears?

John

Clutch probably not fully disengaging. If everything is fitted and adjusted correctly you will need to eliminate any wear in the clutch arm, plunger and pivots area.

Similar problems below quoted from the Forums:-
“If there is any wear on the clutch arm ball it will have a big impact on the operation of the clutch and also it depends on how much wear there is to the hole in the plunger that the ball pushes against.
These two things are the most commonly overlooked problem areas on clutches. You need a minimum 1/2" and preferably 5/8" movement of the Arm at the Clutch Slave cylinder Pushrod.
But don't ignore a worn ball on the clutch lever or ANY wear in any of the axis holes in the push rod or clutch arm. Replacing or repairing any worn components of the Mini clutch operating system is vital to ensure a good clutch. Even a small amount of wear in a clevis pin can have quite a dramatic effect.”

“Gear selection was temperamental and latterly had become hard and difficult to engage – as though there was insufficient throw of the clutch lever/arm (2A 3518). The outwardthrow of the clutch arm via the push rod and hydraulics should be 15mm or 5/8” or .625”

“After getting the engine in the clutch didn’t disengage properly. It was running out of stroke in the slave cylinder - this was due to wear in the plunger and clutch arm. I’d used reasonably good condition used parts but there was too much wear to work with this engine. Changing over the plunger took a couple of hours on Saturday but the outcome was definitely worth it!”

Primary gear drag is another possibility as the oil ways clog up???

Last thing to look at but keep it in mind as I had that happen once on a 'rested' engine.

Thanks for your suggestions to remedy the problem, I have looked at the the movement of the components from the pedal to the clutch cover again today and found the following after setting the recommended clutch arm clearances.

The system has been filled with fluid and purged.
The clutch pedal pressure feels very light when operated.
The master cylinder has been replaced.
The slave cylinder and return spring have been replaced.
The push rod moves out towards the clutch arm connection 20mm.
The clutch arm is an original one that hasn't been replaced.
Both clevis pins have been replaced.
The clutch arm throw out plunger and bearing have been replaced.

In view of the number of parts that I have already replaced it would make sense at this stage to replace the clutch arm.
If that doesn't fix the problem, could the reason for not being able to select gears when the engine is running be related an incorrect installation of the new clutch plate etc?

John

You haven’t mentioned the clutch over throw stop. With all those changes the clearance for the stop may have altered. Back the nuts right off, reset your clutch adjustment, then see if you can disengage correctly. Then run the procedure for setting the stop.

D

Dearg1275 wrote: ↑Mon Jun 01, 2020 8:40 pm You haven’t mentioned the clutch over throw stop. With all those changes the clearance for the stop may have altered. Back the nuts right off, reset your clutch adjustment, then see if you can disengage correctly. Then run the procedure for setting the stop.

D

I adjusted the throw out stop and the clutch arm stop clearance but it didn't make any difference to the problem.

John

You could try putting a 1/4 nut on end of rod near piston of slave cylinder, if this makes it disengage properly then it will be wear in the moving parts, I had issues with mine and it was a combination of wear in the slot of the plunger in the end cover and wear on the ball of the rod, Swapping parts for better used ones solved my problem,
On the adjustment are you pulling slack out of the arm and then adjusting the small 1/4 dia bolt.

AndyPen wrote: ↑Mon Jun 01, 2020 8:34 am Primary gear drag is another possibility as the oil ways clog up???

Last thing to look at but keep it in mind as I had that happen once on a 'rested' engine.

Sorry to repeat myself but this was not at all uncommon in race cars some years back, which is one reason why my 970S is 'extra cooled by holes in the 'wok' cover. The primary gear expanded with heat and locked up. They do this when the oil holes get clogged up too, which can be more erratic to spot until it finally seizes. The symptoms are identical to what you describe, so if all else fails, why not remove the starter motor, look for a mounting hole for the backplate and observe how it moves when someone (socially distant of course) presses the clutch pedal.

If it appears to be moving OK, then that's one test done. If you can find the right screwdriver it is just about possible to try and move the clutch centre plate (when the pedal is down) to check it moves / spins OK. If not, you know it has seized up, and the primary gear is the most likely culprit.


I really hope the arm solves it for you!!

Had a similar problem with a car I bought, a couple previous owners had tried various remedies to get the clutch to work such as new clutch arm, lengthening the pin etc. when all the time it was this!

WTF !!!!

eheh... i've seen missing crank thrust washers, missing bearing on box mainshaft nose, both synchro hubs with only two springs/balls per hub... but this is the best i've seen

Cammsjb wrote: ↑Mon Jun 01, 2020 8:06 pm In view of the number of parts that I have already replaced it would make sense at this stage to replace the clutch arm.
If that doesn't fix the problem, could the reason for not being able to select gears when the engine is running be related an incorrect installation of the new clutch plate etc?

John

As you say I would replace the clutch arm next and that should eliminate any of the common wear issues.

LuisM wrote: ↑Tue Jun 02, 2020 1:28 pm eheh... i've seen missing crank thrust washers, missing bearing on box mainshaft nose, both synchro hubs with only two springs/balls per hub... but this is the best i've seen

Have to agree with that!!!!

Maybe a stupid question but what is the central raised Tit for on the Flywheel to Crank securing Bolt for ?
Best i remember the early version of this end of Crank Bolt were just a flat face on the Hexagon .

One of my old pullers has a recess for it, so centralisation???

This one?

Polarsilver wrote: ↑Wed Jun 03, 2020 8:51 am Maybe a stupid question but what is the central raised Tit for on the Flywheel to Crank securing Bolt for ?
Best i remember the early version of this end of Crank Bolt were just a flat face on the Hexagon .

Yes as seen in the photo ..the central "Tit" seen on the Crankshaft Bolt .. just asking what is the reason for this round raised area on the big bolt head .. i suspect Andy is correct that it locates into a Puller to stop side slip of the Flywheel Puller when taking off the Flywheel .. or is this mystery Tit for some other reason as it was not around on early cars?

Is it not for stopping clutch over throw .The bolt would be removed when using the puller .

One more thing to check is the clutch pedal, if the hole in it is oval or too much play in the bush you won’t get enough travel to operate the clutch fully.

The " horseshoe " you fit on the taper locks the clutch gear due to the flywheel has no clearence. Grind off 2/10 of a mm wherre they meet and I hope you will be fine.