Setting the Clutch throw / stop

[S6PNJ]

I'm about to bite the bullet and pull my clutch apart as I have a leaking slave (well, to say it is leaking is a slight understatement...). Having read a million and one threads on here about clutches, slaves, seals, disassembly etc, I read that there is (or should be) a rubber bump stop on the clutch pedal. Mine has never had that but just has the socket head screw and lock nut to set max travel. Where would I get one of these rubber stops from? Any source / supplier / part number or even puicture for them please?

Once I've sorted my slave (and master and clutch) I then need to adjust the throw to make sure I don't over extend the clutch. I've read that it is possible with the car in first gear, one person trying to push the car (or turn the road wheel if wheels not on the ground) with another person pressing the pedal until the clutch releases. How is this postion then marked as to get to the adjuster, the person's foot / body / /mass is in the way? Any tips and tricks?

Also, if I shouldn't over extend the clutch, but I need to bleed a completely empty clutch hydraulic system, is there any special (or recommened) method so as to ensure I don't over throw the clutch?

Once I've done it, I'll know what I'm doing for the next time, but hopefully the next time will be a fair few years down the road, by which time I'll have forgotten it all again!


Edited to add - I've also read that some folk have swapped the 0.700" clutch master cylinder for a 0.625" master cylinder. Recommended or just stick with the 0.700" ?

[nawarne]

I'm guessing here - but I'd imagine most TVR service folks vacuum the fluid through to the bleed nipple?

I've never had a rubber stop/cover for the clutch travel 'bolt'
Nick

[S6PNJ]

It has taken me some time, but I'm now at / past the clutch bleeding point and trying to set the clutch stop correctly. I currently have the stop set so that when the pedal is at full throw (against the stop), I can rotate the clutch plates by hand (using the alignment tool). But this doesn't allow for any wear as the clutch goes through its life, so knowing that the throw should not be over extended - how much is 'over extended' and how much more than 'clutch plates releasing' can I give to the pedal?

Gearbox will be going back on this afternoon hopefully, so any future clutch releasing will be by moving the car in gear.

[Basil Brush]

S6PNJ said:

It has taken me some time, but I'm now at / past the clutch bleeding point and trying to set the clutch stop correctly. I currently have the stop set so that when the pedal is at full throw (against the stop), I can rotate the clutch plates by hand (using the alignment tool). But this doesn't allow for any wear as the clutch goes through its life, so knowing that the throw should not be over extended - how much is 'over extended' and how much more than 'clutch plates releasing' can I give to the pedal?

Gearbox will be going back on this afternoon hopefully, so any future clutch releasing will be by moving the car in gear.

The over extended part is about not pushing the fingers on the diaghram spring to the point where the spring can't move anymore and you're just bending the fingers, causing them to fatigue and snap. I think AP give a max slave movement of 8mm for the clutch type. As the clutch wears the fingers will push the slave further back but the travel needed to release will stay the same at the pedal, meaning the max diaghram movement at full release will be less as the clutch ages.

[Modrich]

if you don't get a satisfactory reply here, maybe speak to CG Motorsport who rebuild these AP clutches, they've done one for me and were very helpful. I will be fitting at some point as I think I have a slave leak also.

[S6PNJ]

Basil Brush said:

The over extended part is about not pushing the fingers on the diaghram spring to the point where the spring can't move anymore and you're just bending the fingers, causing them to fatigue and snap. I think AP give a max slave movement of 8mm for the clutch type. As the clutch wears the fingers will push the slave further back but the travel needed to release will stay the same at the pedal, meaning the max diaghram movement at full release will be less as the clutch ages.

Thanks, I know / understand the mechanics of it - how and why it happens, I'm just trying to make sure it doesn't happen whilst still being able to adjust the clutch as needed.

Modrich said:

maybe speak to CG Motorsport who rebuild these AP clutches,

They rebuilt this clutch for me about 1 week ago.

[Basil Brush]

S6PNJ said:

Thanks, I know / understand the mechanics of it - how and why it happens, I'm just trying to make sure it doesn't happen whilst still being able to adjust the clutch as needed.

Apologies in that case. Why would you need scope to adjust once set?

[S6PNJ]

Basil Brush said:

Apologies in that case. Why would you need scope to adjust once set?

At first installation, with a brand new (well, refaced) flywheel, there may be initial wear / settling in etc. I've adjusted the pedal so that at max throw (on a longer than previously fitted stop - I REALLY don't want to break this clutch and have to do it again), the clutch plates disengage so they can be turned by my 3D printed alignment tool (). I'm sure, since 2007 (last time the clutch was replaced - but not necessarily adjusted) that I didn't need to go full onto the stop to disengage the clutch, so it's more a question of how much further can I go before affecting the spring fingers so that I don't need a full depress of the clutch every time (ie easier to change gear if not at full throw).

[Basil Brush]

Fair enough.

Have you played around with the pedal pushrod at all, in terms of travel vs pedal weight?

I had a handle on mine with the standard slave but currently putting a Tilton in so will have to start again.

[S6PNJ]

Basil Brush said:

Fair enough.

Have you played around with the pedal pushrod at all, in terms of travel vs pedal weight?

I had a handle on mine with the standard slave but currently putting a Tilton in so will have to start again.

I had played with it previously (dunno - maybe 10 years or so ago?). it's currently set on the lower hole (clutch pedal) to upper hole (clutch lever) then the upper hole on master cylinder lever. Earlier today I did try it on the upper clutch pedal hole, but that just gave more throw on the master which was what I was trying not to do (with that setting, it was way off the end stop when the clutch was disengaging).