Clutch pedal travel

[RdeJ]

Just before going on vacation I changed the standard gearbox for an A-type in the TR3.

...wandering if this is the right momentum to do such an 'exercise', yes the old gearbox was grumbling to loud.

While all was out, replaced the top bearing behind the flywheel, 3-finger clutch-cover, plate and main clutch-bearing.

Reused the bronze bearing carrier and fork, though installed an ' uprated' fork pin and added a rollpin in the shaft. Some items fitted with minimum ceramic grease.

All is working well, though compared to the old setup the clutch grip sits deeper on the pedal.

The problem I am currently facing is that after each day-trip ~70 miles I need to adjust the slave-rod because the clutch does not release properly anymore. Else getting it into first or reverse is a struggle.

I have now moved the slave cilinder rod into the top hole to gain a minor extra travel. It has a return spring fitted and the slave bracket has the support rod fitted to bottom engine.

Are the fork teeth digging into the bearing carrier?

 

Robert

[RogerH]

Hi Robert,

the latest offering of bronze bearing carriers (bright yellow) are the wrong material for the fork with the round pins.

You need either the harder Phosphour bronze (dark gold) or steel carrier.

 

The slave should be connected to the centre hole on the cross shaft arm - as you know.

Check all the pivots and joints from master cylinder to slave and ensure they are all virtually perfect.

On the 4A the bracket that holds the slave cylinder does not allow the slave to be square t the arm. I made my own

 

Have you bled all the air from the slave. Is the bleed nipple at the 12-o-clock position.

Is the Hydraulic plastic [pipe to the slave still in good condition (swelling)

 

Roger.

Edited September 14, 2018 by RogerH

[RdeJ]

Tx Roger,

 

Have not had the sleeve cylinder tube disconnected while exchanging the gearbox, so don't expect air in the system. Will check it later when back home again. ...yes the bleed niple is at 12:00 hr. Tube looks good (from outside...)

Reading your comments about checking joints of the master cylinder I tot triggered that there is an adjustable rod here too. That's behind the wipermotor (LHD). Was to much focussed on just the slave rod.

So moved back the slave rod to the center lever hole. Next adjusted the rod length at the master cylinder. At least now the clutch grip is higher at the pedal.

But for how long?

 

Robert

[RogerH]

Hi Robert,

check all the pins and holes for roundness. Any wear in the system causes chaos.

 

Roger

[RdeJ]

Meanwhile I have readjusted the clutchlever arm free play a couple of times after each trip and the clutch pedal is at maximum hight now. It is not possible anymore to free-up the clutch. It's rather an adventure to get it into 1st gear, next the car starts crawling forwards and picks up directly at pedal lift.

I've had the clutch pedal pressed overnight and the lever did not changed from position (under tension of the clutch and external return spring)

The slave gives about 20 mm travel on the clutchlever. By measuring the fork from the old gearbox and old clutchplate-levers, that should give aprox. 4 mm release distance at the frictionplate. That should be enough? Does anybody has the measurements of the slave cylinder while pressing the pedal?

....already start preparing for the gearbox out again (mentally)

[Waldi]

Hallo Robert,

Re-adjusting the clutch after a days drive is not normal; there should not be any wear like that. Is something bending (hope not) or wearing out quickly (possibly).

Is there any grumbling noise when pressing or releasing the pedal?

Waldi

[RdeJ]

Hallo Waldi,

Thats my take too, should not be nessesary to adjust so frequently.

There is no grumbling sound while pressing the pedal, though a minor squaling sound starts to arise the last week. Think it is the new clutch-bearing giving up but can  not imagine that it is responsible for the lost of so much axial travel at this stage.

Robert

[Fireman049]

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Edited April 16, 2020 by Fireman049

[iain]

I have recently had an almost identical problem......the slave cylinder was not returning properly so i ended up with variable clutch operation.( hence the need for multiple adjustments of the rod length). I changed the slave for a refurbished unit and hey presto, fixed! Try pushing the fork back to its rest position with your fingers.....if you can, then it would appear its sticking on the return travel.

Iain

Edited October 15, 2018 by iain

[Waldi]

“Try pushing the fork back to its rest position with yourfingers.....if you can, then it would appear its sticking on the return travel.“

Isn’t that is normal, there is a spring in the bottom of the slave cylinder to achieve a pre-load to ensure the clutch bearing is in contact with the diaphragm.

I stand to be corrected.

Waldi

[Lebro]

For early TR's the spring is there to do the opposite ! it pulls the bearing away from the clutch.

The trick is to adjust the length of the rod so that the spring pulls the fork back a very small amount.

 

later TR's do not have the spring fitted, so the bearing is in light contact with the clutch.

[RdeJ]

I have replaced the slave cylinder 3 years ago it is running smooth while manualy pressing the rod to inside. Like Waldi's comment it has an internal spring which is gently moving the rod outwards, the stronger outside clutch return spring is working against the internal one and (if adjusted correctly) free the clutch-bearing from the clutch-plate fingers.

Guess the shorter slave-cylinders do not ave the external spring.

Robert

[RdeJ]

Tom, were you able to determine why/how the non Laycock clutch plate was causing issues?

Robert

Edited October 15, 2018 by RdeJ

[Fireman049]

.

Edited April 16, 2020 by Fireman049

[stuart]

1 hour ago, Fireman049 said:

Hi Robert ~

I'd purchased a 'cheap' clutch assembly from a TR supplier. John Sykes guessed that the pressure plate was a Ford or something unit.

Tom.

Transit one was often sold as being "Suitable"

Stuart.

[Fireman049]

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Edited April 16, 2020 by Fireman049

[RdeJ]

OK, the gearbox is out and believe have found the culprit.

The pressure-plate has 3 fingers which are at uneven axial depth in relation to the plate/bearing, thats wrong. The distance between  highest and lowest position is 5 mm. Should be 0. Seems that it is caused due to the 3 adjustment nuts where not locked properly and have ran out of possition. When zooming into the nut you can see that the slot is not alligned anymore. They must have been unwinded and have caused the clutch pedal travel requirement adjustment everytime.

As they have unwinded uneven it caused the clutch-plate to be not in paralel with the friction plate. At the third picture you can see the dark area which was closed towards the friction plate and took the first grip. In addition on the friction plate you can see a darker ring at the outside caused by the presure-plate sitting deeper at one side.

So back to the supplier for a claim on the wrong assembled clutch-plate and the need for a replacement bearing since that one has been uneven presured in its early life.

Robert

 

[Lebro]

Now I can see which type of cover you have, I can say the it would normally have an adjustable pushrod on the slave cylinder along with a return spring.

Bob.