50 replies to this topic

[Ethel]

...bit of an aside.

 

Just trying to get my head round the effect of clutch plate wear - to my thinking it would improve your situation as a thinner friction plate would allow the back plate to come closer to the release bearing?

 

Of course, it'd be a lot more marginal than anything mentioned so far.

[Spider]

I find with all new parts and set up right, the take up point is around when the pedal is half way up from the floor or maybe a bit closer to the floor.

 

Copy that you have checked the PIns etc, Just to ask the question here, what about the Hole in the Clutch Cover that the bigger Pin for the lower end of the Arm? I find probably 1 in 5 or so of these to be worn.

 

Also, at 50% travel, the very end of the Arm, with the Ball End, should be close to 90 degrees to the Plunger. It's surprising the big difference this makes. as the angles reduce from 90⁰, the effective Plunger Travel for Arm Movement reduces as it's moving through an Arc on a small radius.

 

Unlikely, but just to put it out there as I've been caught on this one. There has been 2 lengths in the Slave Push Rods. The early Spring Clutches used a Shorter Push Rod.

 

Noted you haven't replaced the Master Cylinder. I will suggest at the very least, it would be worth overhauling it with a hone and new seals. The Clevis on these do also wear. Given that that only have around 22 mm of Travel, it doesn't take much wear here to add up to a lot at the Thrust Bearing.

 

I have also had soft Thrust Plates on the Diaphragms a few years back. I doubt you'd be supplied one of these now, but these wore very fast under the Bearing and they also flexed, reducing effective travel.

 

When setting all the adjustments, I set the Over-throw stops on the Bench, though, they can be done in car. I Put a pipe over the arm, pull it out all the way to a hard stop, then wind down the Flanged Nut to the Clutch Cover, release the Arm, then wind it on a further 1/2 a turn and lock it off there. That should never need to be touched again until the Flywheel is next removed. The Arm Stop I set by removing the Arm Spring, winding the bolt until it contacts the Arm, then wind back in until there is some clearance there, I've never bothered to measure it, but I'd say I set them around 0.010" - just enough to allow from Crank End Float and so the Bearing doesn't contact the Thrust Plate.

 

One last item comes to mind here. It might also be worth checking the Ball End on the Arm. I know you have replaced it, however that end of the Arm is induction hardened. I've had one and seen a couple of others where it appears that the hardening process has enbrittled that end of the Arm and just under the Ball, they have cracked.

[nicklouse]

Chris, you mention the Wok pivot. What is the best way to check it for wear and how to rectify it is worn?

 

or is there a good way to make sure it does not wear. 
 

to be honest I have not really looked for wear there are it always seems to be the pin that is worn by the arm.

[Spider]

Nick, you can usually see the wear easy enough

 

 

It seems to happen when the Pin gets rusted in the Arm.

 

The hardest part about repairing them is working out where the original centre was. I've done a couple by machining these bigger and fitting Bronze Bushes, though, really, they only need to be Aluminum as the Pin usually 'bites' the Aluminum and the Arm swings on the Pin.

[unburntfuelinthemorning]

...bit of an aside.

 

Just trying to get my head round the effect of clutch plate wear - to my thinking it would improve your situation as a thinner friction plate would allow the back plate to come closer to the release bearing?

 

Of course, it'd be a lot more marginal than anything mentioned so far.

And that's why you have to adjust the clutch periodically or that'll start slipping.

[unburntfuelinthemorning]

I find with all new parts and set up right, the take up point is around when the pedal is half way up from the floor or maybe a bit closer to the floor.

 

Just to ask the question here, what about the Hole in the Clutch Cover that the bigger Pin for the lower end of the Arm? I find probably 1 in 5 or so of these to be worn.

 

Also, at 50% travel, the very end of the Arm, with the Ball End, should be close to 90 degrees to the Plunger. It's surprising the big difference this makes. as the angles reduce from 90⁰, the effective Plunger Travel for Arm Movement reduces as it's moving through an Arc on a small radius.

 

Unlikely, but just to put it out there as I've been caught on this one. There has been 2 lengths in the Slave Push Rods. The early Spring Clutches used a Shorter Push Rod.

 

Noted you haven't replaced the Master Cylinder. I will suggest at the very least, it would be worth overhauling it with a hone and new seals. The Clevis on these do also wear. Given that that only have around 22 mm of Travel, it doesn't take much wear here to add up to a lot at the Thrust Bearing.

 

I have also had soft Thrust Plates on the Diaphragms a few years back. I doubt you'd be supplied one of these now, but these wore very fast under the Bearing and they also flexed, reducing effective travel.

 

When setting all the adjustments, I set the Over-throw stops on the Bench, though, they can be done in car. I Put a pipe over the arm, pull it out all the way to a hard stop, then wind down the Flanged Nut to the Clutch Cover, release the Arm, then wind it on a further 1/2 a turn and lock it off there. That should never need to be touched again until the Flywheel is next removed. The Arm Stop I set by removing the Arm Spring, winding the bolt until it contacts the Arm, then wind back in until there is some clearance there, I've never bothered to measure it, but I'd say I set them around 0.010" - just enough to allow from Crank End Float and so the Bearing doesn't contact the Thrust Plate.

 

One last item comes to mind here. It might also be worth checking the Ball End on the Arm. I know you have replaced it, however that end of the Arm is induction hardened. I've had one and seen a couple of others where it appears that the hardening process has enbrittled that end of the Arm and just under the Ball, they have cracked.

I would have expected the biting point to be around half way.

 

I didn't pay a lot of attention to the size of the hole for the larger pin but it wasn't sloppy or noticeably worn.

 

I'll check the angle of the arm in relation to the plunger.

 

The length of the plunger shouldn't matter as long as the slave piston isn't reaching the end of its travel in either direction;  is that a correct assumption?  I don't think it is reaching the end if its travel but I shall check.

 

I think I'll change the master cylinder anyway and sort out the clevis pin play while I'm there.

 

Hopefully not the thrust plate.  It's an AP one which came with the diaphragm.

 

I've adjusted the throw out stop as the manuals describe where you press the clutch fully, screw in the stops, release clutch pedal, turn stop one more flat and lock.  I realise that if the external mechanism isn't working correctly and giving enough travel that the throw out stop will be screwed in too much.

 

I had the arm out recently to inspect it as I was concerned I'd bent the end of it but I hadn't and it was all in good condition.  I have managed to bend the end of one before which was rather annoying.

Edited by unburntfuelinthemorning, 13 November 2019 - 02:11 PM.

[nicklouse]

Nick, you can usually see the wear easy enough

 

 

It seems to happen when the Pin gets rusted in the Arm.

 

The hardest part about repairing them is working out where the original centre was. I've done a couple by machining these bigger and fitting Bronze Bushes, though, really, they only need to be Aluminum as the Pin usually 'bites' the Aluminum and the Arm swings on the Pin.

Now that they are getting harder to find would you take preventative measures and sleeve a good one so it is an easy fix?

 

or as I am most likely going to do just hope I don’t have issues? 

[Spider]

Nick, as a matter of course, I'm not sleeving these holes. If they are good, I leave them. If they are worn, I repair them rather than toss.

 

The other items I am find a few of that wears on these is the bore for the Plunger. Again, I bore these true on an over-size (after clocking up to the outer spigot) , sleeve with Aluminum, then bore back to size.

 

For this and the Clevis Pins, I smear some Molly Grease on them. Of late, I'm also shoving some sponge rubber in the Gap that's between the Arm and the Cover itself. This seems to be a bit of an 'Ashtray' picking up all manner of grime that only causes them to wear. I can't yet say how effective this is.

[unburntfuelinthemorning]

To follow up:-

 

The very end of the arm with the ball end is around 90^o to the plunger when the arm is at rest.

 

The slave cylinder still has further travel in reserve in either direction so isn't running out of travel.

 

I've left the pedal wedged down to see if it holds pressure.

[timmy850]

When I did my clutch system recently I added a washer on the plunger before the bearing goes on.


With the other new parts you can see the improved angle of the clutch arm. This gave a really nice pedal feel and disengages in the top 1/2 of the travel. Previously the slave was running out of travel

[Ethel]

 

Nick, you can usually see the wear easy enough

 

 

It seems to happen when the Pin gets rusted in the Arm.

 

The hardest part about repairing them is working out where the original centre was. I've done a couple by machining these bigger and fitting Bronze Bushes, though, really, they only need to be Aluminum as the Pin usually 'bites' the Aluminum and the Arm swings on the Pin.

Now that they are getting harder to find would you take preventative measures and sleeve a good one so it is an easy fix?

 

or as I am most likely going to do just hope I don’t have issues? 

 

If you have a good 'n, you could use it to make a locating jig in case you do ever have to bush one.

[Ethel]

When I did my clutch system recently I added a washer on the plunger before the bearing goes on.


 

As long as the washer doesn't bridge the inner and outer races.

[unburntfuelinthemorning]

The clutch was still in the same disengaged position after having the pedal wedged overnight so that's good. 

 

I have discovered a little weeping of fluid from the pipe to hose connection.  It doesn't seem to be letting air in but a small amount of fluid is escaping when the system's under pressure, probably a dodgy flare on the pipe. 

 

Obviously this is no good but I don't think it's the answer to my clutch biting point problem.  I'll get another master cylinder soon and replace that along with the pipe and fit a new clevis pin and see where things are then.

[Spider]

Can you post up a photo of the relationship of the Clutch Cover, Arm and Slave ?

[unburntfuelinthemorning]

Here we go:

 

 

 

And here's some with a worn but un-bent arm laid over the existing one: