having an issue with constant clutch drag on a mk1 850 with the "long wand" style shifter. have adjusted the release bearing and stop screw thing by the book. hydraulics have been bled of air and hold pressure like they should.
at a stop, clutch depressed, it grinds into 1st or reverse. leave the clutch depressed, shift to neutral, still grinds when trying to shift into gear.
any advice? sound like a problem internally or still something out of adjustment?
Dragging clutch!
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Tim
- 1275 Cooper S
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Re: Dragging clutch!
Sounds like wear. There is only limited adjustment available and it can't always compensate for accumulated losses due to wear in the complex path between the pedal and the clutch disengaging. In effect, you lose clutch throw over time. It can be anything from an ovalised hole in the end of the clutch pedal, a worn clevis pin, worn clevis on the master cylinder, worn ball on the end of the clutch throwout arm, or worn hole in the throwout bearing carrier. Or just a little bit of wear in all of those places.
You can sometimes demonstrate it by having a helper gently lever the clutch arm further out using a pry bar, and trying to engage gears. If it slips in nicely its usually an indication that there isn't enough throw.
Common bodges are to lengthen the slave cylinder pushrod, or bend the clutch throwout arm, but replacing or re-bushing the worn parts is the best solution.
Tim
You can sometimes demonstrate it by having a helper gently lever the clutch arm further out using a pry bar, and trying to engage gears. If it slips in nicely its usually an indication that there isn't enough throw.
Common bodges are to lengthen the slave cylinder pushrod, or bend the clutch throwout arm, but replacing or re-bushing the worn parts is the best solution.
Tim
1951 Morris Commercial J Type Van
1955 BSA C11G
1961 Morris Mini Traveller
1969 Triumph TR6R
1977 Leyland Moke Californian
1955 BSA C11G
1961 Morris Mini Traveller
1969 Triumph TR6R
1977 Leyland Moke Californian
-
ianh1968
- 1275 Cooper S
- Posts: 1012
- Joined: Sat Nov 03, 2012 6:00 pm
- Location: West Sussex
Re: Dragging clutch!
Unfortunately, there has been a minor meltdown on the forum and
a few posts have disappeared...
Well Done to Mark F for getting it fixed again...
I'll try to recreate what was here before it went AWOL.
Much of this is based on what OTHER people posted...
Thanks to those other members!
With the dragging clutch, the following are possible suspects:
1) Out of adjustment
2) Air in the hydraulic system or "ballooning" flexible hose
3) General wear, in ANY of the mechanical parts.
4) Primary gear sticking on crank tail
5) Actuation plunger installed incorrectly
6) Broken off ball end
... and possibly several others.
1) Out of adjustment:
The small 7/16" AF bolt with the locknut is there to compensate for
wear of the friction disk. What is actually being set here is the gap
between the release bearing and the thrust washer.
Too big a gap here means that too much of the pedal travel is used
up just closing up the fresh air gap between these parts, then not
leaving enough left to fully disengage the clutch.
If closing the gap up to almost nothing makes things better, this
would strongly suggest that wear/slop is the culprit.
There needs to be a gap because things move about and with
no gap or not enough gap, the bearing will be spun each time the
crank moves sideways in that direction.
DON'T RUN WITH TOO SMALL A GAP - YOU CAN GO LESS THAN 15 THOU
BUT IT IS NOT RECOMMENDED.
The large throwout nuts are nothing to do with this, they only stop
the crank from being pushed too far towards the pulley end and wearing
out the centre main bearing thrust washers.
2) Air in the hydraulic system or "ballooning" flexible hose
Bleed the system, as implied. Also old hoses tend to break down
through age and some of the pedal movement gets used up just
expanding the rubber hose. Replacement is the only cure.
3) General wear, in ANY of the mechanical parts.
Starting at the pedal clevis, change the pin for a new one. The actual forks
also tend to go quite oval with age.
If the master cylinder is due for replacement, replace it,
otherwise, consider this:
http://www.carbuildersolutions.com/uk/5 ... der-clevis
Also change the pins at both ends of the actuation arm.
If the clutch housing is also oval, this is what I use:
http://www.wdsltd.co.uk/product/3244/so ... ic-wds-615
I don't get them from here, but they are the same thing.
The housing and arm both need reaming out to 10mm, but this is often
easier and/or quicker that getting some bushes fitted. The hex in the
end is 5mm, so an allen key will be required and a 13mm spanner for the
nut (Nyloc) - I find it easier to shorten the short arm of the allen key as
I normally fit these with the nut at the front...
NOTE: The 40mm length screws are perfect - The nut to head dimension
MUST NOT not cause the arm to get clamped in the casting. I put a thick
10mm washer front and back which removes most but not all of the endfloat.
4) Primary gear sticking on crank tail
Either it was too tight when fitted, or it has got "gummed up".
Try starting the engine with your foot on the clutch and the car in gear.
Make sure the handbrake is firmly on and the wheels chocked!
Sometimes this will help, but mostly it won't...
Get the flywheel off and sort it out...
5) Actuation plunger installed incorrectly
The actuation plunger has a big recess/lead where the ball-end goes,
and only a small hole right through to the other side. If this is 180
degrees wrong, the clutch will not work properly due to it having
a mechanically restricted movement.
I managed to do this myself once, but this was with an "uprated" type.
I am sure that this would very quickly cause No6...
6) Broken off ball end
As implied.
7) Other re-submissions to this re-built thread are welcome,
I just can't remember what they all were...
Ian
a few posts have disappeared...
Well Done to Mark F for getting it fixed again...
I'll try to recreate what was here before it went AWOL.
Much of this is based on what OTHER people posted...
Thanks to those other members!
With the dragging clutch, the following are possible suspects:
1) Out of adjustment
2) Air in the hydraulic system or "ballooning" flexible hose
3) General wear, in ANY of the mechanical parts.
4) Primary gear sticking on crank tail
5) Actuation plunger installed incorrectly
6) Broken off ball end
... and possibly several others.
1) Out of adjustment:
The small 7/16" AF bolt with the locknut is there to compensate for
wear of the friction disk. What is actually being set here is the gap
between the release bearing and the thrust washer.
Too big a gap here means that too much of the pedal travel is used
up just closing up the fresh air gap between these parts, then not
leaving enough left to fully disengage the clutch.
If closing the gap up to almost nothing makes things better, this
would strongly suggest that wear/slop is the culprit.
There needs to be a gap because things move about and with
no gap or not enough gap, the bearing will be spun each time the
crank moves sideways in that direction.
DON'T RUN WITH TOO SMALL A GAP - YOU CAN GO LESS THAN 15 THOU
BUT IT IS NOT RECOMMENDED.
The large throwout nuts are nothing to do with this, they only stop
the crank from being pushed too far towards the pulley end and wearing
out the centre main bearing thrust washers.
2) Air in the hydraulic system or "ballooning" flexible hose
Bleed the system, as implied. Also old hoses tend to break down
through age and some of the pedal movement gets used up just
expanding the rubber hose. Replacement is the only cure.
3) General wear, in ANY of the mechanical parts.
Starting at the pedal clevis, change the pin for a new one. The actual forks
also tend to go quite oval with age.
If the master cylinder is due for replacement, replace it,
otherwise, consider this:
http://www.carbuildersolutions.com/uk/5 ... der-clevis
Also change the pins at both ends of the actuation arm.
If the clutch housing is also oval, this is what I use:
http://www.wdsltd.co.uk/product/3244/so ... ic-wds-615
I don't get them from here, but they are the same thing.
The housing and arm both need reaming out to 10mm, but this is often
easier and/or quicker that getting some bushes fitted. The hex in the
end is 5mm, so an allen key will be required and a 13mm spanner for the
nut (Nyloc) - I find it easier to shorten the short arm of the allen key as
I normally fit these with the nut at the front...
NOTE: The 40mm length screws are perfect - The nut to head dimension
MUST NOT not cause the arm to get clamped in the casting. I put a thick
10mm washer front and back which removes most but not all of the endfloat.
4) Primary gear sticking on crank tail
Either it was too tight when fitted, or it has got "gummed up".
Try starting the engine with your foot on the clutch and the car in gear.
Make sure the handbrake is firmly on and the wheels chocked!
Sometimes this will help, but mostly it won't...
Get the flywheel off and sort it out...
5) Actuation plunger installed incorrectly
The actuation plunger has a big recess/lead where the ball-end goes,
and only a small hole right through to the other side. If this is 180
degrees wrong, the clutch will not work properly due to it having
a mechanically restricted movement.
I managed to do this myself once, but this was with an "uprated" type.
I am sure that this would very quickly cause No6...
6) Broken off ball end
As implied.
7) Other re-submissions to this re-built thread are welcome,
I just can't remember what they all were...
Ian