Clutch Won't Disengage

Started by Rosebud, July 11, 2020, 01:55:17 PM

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Rosebud


I was parked for about an hour and when I jumped into the car, the clutch wouldn't disengage. The pedal went all the way to the floor with very little resistance. The clutch master and slave cylinders seem to be working OK and the clutch arm is moving through its full range.


Anyone care to give me a diagnosis? Also, when it's time for me to open it up, what's the consensus, do I leave the motor in, or do I take the motor out? I understand the clutch can be replaced w/ the motor in the car, just wondering which is easier as I have never pulled a motor or rebuilt a clutch. All opinions welcome. Thanks!
Rosebud
...the sled, not the flower
https://www.facebook.com/PoserMotorSports

94touring

The only way I've been able to leave the engine in was by cutting a small hole in the inner wing to get the tooling in there for pulling the flywheel. Your car being as nice as it is, that may not be ideal.  It's been awhile since I've had to do a clutch job so maybe someone has come up with a better solution since.

MPlayle

Before pulling it all apart, remove just the arm and check the ball on the end.

You may be getting arm movement, but not plunger movement if the ball has cracked loose.


John Gervais

Quote from: MPlayle on July 11, 2020, 02:15:34 PM
Before pulling it all apart, remove just the arm and check the ball on the end.

You may be getting arm movement, but not plunger movement if the ball has cracked loose.

That happened to me once.
- Pave the Bay -

MiniDave

Is this a Verto or Pre-Verto clutch? Makes all the difference on whether you can change it in the car with a Verto being much easier. However, based on your description I'd bet on something being broken, like the others have said. If you have someone stroke the clutch pedal and you see complete movement of the clutch arm the most probable thing is a broken ball on the end of the clutch arm, very unlikely that there's something broken inside the clutch itself based on your description.

Let us know what you find?.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

MPlayle

Having viewed the video linked in the Mini Mania posts, I now suspect the stop nuts have walked in just enough to prevent proper clutch movement.

Yes, the nuts can creep in and still seem tightly jammed.  (Actually, the shaft of the plunger creeps out.)

Back the plunger stop nuts off to about double or triple the current gap of the plunger pulled out.  Reassemble and temporarily leave off the clutch arm return spring.  Adjust in the arm stop bolt in slightly.  This should give room for the system to settle at its natural release point.  Make sure the system is fully bled and then see if the clutch operates properly.  If so, it will settle to the point where the throw-out bearing is held out by the return spring action of the clutch itself.  Move the plunger in to where the throw-out bearing just contacts the clutch.  Reset the arm stop bolt to basically just barely hold the plunger at that position.  Then have an assistant press the clutch pedal in so you can observe and judge the travel required by the plunger before resetting the plunger stop nuts to permit no more than the full travel.

The very last thing to do is replace the clutch arm return spring.  Its purpose is to pull the arm the tiniest amount to rest on the arm stop bolt.  Many people actually leave it off and let the clutch's natural return spring action be sufficient.

Most clutch arm return springs are too strong and end up working against weak seals in the clutch master, causing reduced arm travel and thus insufficient clutch operation.


MiniDave

With the clutch return spring off and the clutch arm held out with release bearing against the clutch pressure plate, the stop bolt should have about 20 thou clearance. Also, with the spring reinstalled, the stop nut on the plunger should have 1/8" clearance - I slide a 1/8" drill bit in and leave a loose clearance, then tighten the two nuts against each other.

However, none of these adjustments should be made unless you're sure you don't have a broken or cracked ball end on the clutch arm, or a broken or excessively worn clevis pin anywhere in the system.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Rosebud

#7
It's not a broken clutch arm ball. The last time I had an arm ball fail, I replaced it with heavy duty billet version. It's still good. https://www.facebook.com/notes/poser-motorsports/tiny-crack-big-problem/1915581398514527/


The plunger nut and stop-nut haven't moved. When I fiddle with the plunger it seems like there's hardly any travel. I can't recall how much in & out movement is normal, but clearly this doesn't seem like enough travel to disengage the clutch. https://youtu.be/I2CGpRH6-wI


Some of the folks on another forum think I might have a collapsed release bearing or bearing seat issue—the plunger travel is not nearly what it should be and there's no resistance felt when I move the plunger back & forth. Anyone else have a release bearing failure with these symptoms?
Rosebud
...the sled, not the flower
https://www.facebook.com/PoserMotorSports

Rosebud

It turned out to be a collapsed throwout bearing. I'll take it. It beats changing out the clutch assembly and possibly pulling the motor. I've got a new, heavy-duty bearing on the way.
Rosebud
...the sled, not the flower
https://www.facebook.com/PoserMotorSports

94touring