Toyota 5 Speed and Heavy Clutch

[Rangi246]

Hi all

I've got a 74 P6 V8 that has had a 5 speed Toyota Supra gearbox conversion done. The car changes gears nicely but I have noticed the clutch is very heavy, especially when I compare it to our 65 Triumph Vitesse.

I have noticed the hydraulic setup is using the standard Rover V8 Master Cylinder and a Toyota W58 Slave Cylinder. Is the bore in the Toyota slave cylinder likely to be cause of the heaviness in the clutch? Would changing the slave cylinder/getting it bored out make any difference? Its all been re-bled and has no air in it at all.

I would like the pedal to be a bit lighter, particularly for round town driving. At the moment its just a bit too heavy and ruins the driving experience a little.

Cheers
Mark

 

[cooper1203]

hi from memory making the bore of the slave cylinder bigger would make the clutch heavier if u wanted to make it lighter u would either have to put a smaller bore slave in or a bigger master.

Harvey will be able to deny or confirm this but I think others use a 1" slave cylinder bore
hope this helps
coop

 

[harveyp6]

hi from memory making the bore of the slave cylinder bigger would make the clutch heavier if u wanted to make it lighter u would either have to put a smaller bore slave in or a bigger master.

You have that the wrong way around. Making the master dia smaller relative to the slave dia will make the pedal lighter but with a longer pedal travel.

I can't remember the slave dia offhand.

 

[Rangi246]

I also noticed that the pipe setup is as follows:

Reservoir to clutch master cylinder - standard pipes
Clutch Master to Clutch Slave - starts off as a hose that looks like a brake hose, then connects to a copper pipe, then into the slave cylinder.

Not sure if changing these pipes would make much difference?

 

[harveyp6]

Changing the pipes won't make any difference unless the flexi hose has collapsed internally, which is unlikely as it will hold pressure making the clutch slip when you release the pedal which I would have thought you would have noticed.

 

[Vern Klukas]

hi from memory making the bore of the slave cylinder bigger would make the clutch heavier if u wanted to make it lighter u would either have to put a smaller bore slave in or a bigger master.

You have that the wrong way around. Making the master dia smaller relative to the slave dia will make the pedal lighter but with a longer pedal travel.

I can't remember the slave dia offhand.

Off the top of my head, 7/8 & 1 inch are the bores of the two slave cylinders that were used. The 7/8 bore is the early size, I'm not sure when it changed but surely by 74 it would be the 1" size.

Yours
Vern