Supra Clutches - can you alter the biting point?

The car I have right now has a clutch biting point close to the end of the clutch pedal travel. It's a pain in the arse because you have to push the clutch right to the floor ever time you change gear.

I had an uprated clutch fitted to my old sup and the clutch went from normal to early bite point when I got it back. The new car has the same problem, the first few inches of travel are nowhere near the putting pressure on the clutch plate, then the travel stiffens, activating the clutch.

My local mechanic tells me that "the bite point on Hydraulic clutches can't be adjusted" he may be right but is there an adjustment somewhere else that can or is he talking bollocks, or is he right!?

any advice greatfully received!

The pedal position can be altered.

If you look under the dash at the clutch pedal, the shaft that goes to the master cylinder, just ahead of the clevis where it attaches to the clutch pedal, should have a nut on it. If you turn this nut it adjusts the pedal position. Make sure you use some loctite to lock this off when you're done though otherwise it'll vibrate loose and you'll end up even worse than you currently are.

Also make sure you don't go too made with it the otherway as I think you can potentially end up taking all the slack out of the system, in which case the thrust bearing will be under continual load, and will wear out real quick.

Hope that helps.

Thanks for that -

When you say the position can be altered, does that mean that, by using this nut, the pedal can be lowered closer to the floor, or does it mean that in effect you can pull the activation point of the clutch further towards the top of the clutch pedal travel (ideal scenario)?

shouldn't the position of the clutch pedal be in line with the brake?

or will it all be obvious when I have a look?

I would also like to know the answer to this question ? If one of the Super Brains can help ?

By adjusting the rod you CAN get SOME extra movement at the bearing. Ideally you want either a smaller bore slave cylinder, or a bigger bore master cylinder, though. The usual reason for this problem is US sourced clutches are VERY oftem based on reground (re-conditioned) pressure plates, that, through geometry changes, alter the bite point of the clutch. If you fit a "new" clutch and the pedal needs altering, or, worse case scenario, cylinders need changing, you can be sure the spec of the cover or plate thicknesses varies from stock, and it's nearly always the cover that has been re-conditioned by surface grinding a used unit. Some are based on patently scrap covers, and fall under "Real-Con Clutches" IMO.

It's the pedal position that changes. It's probably this that needs altering with yours. If you just wind that nut in and out until the pedal is about level with the brake pedal and then loctite it in place, you'll probably be fine. The nut on mine was never locked in place (Thanks JPS!) it took me ages to work out what the hell was going on. The symptom was identical to yours. I just wound that nut out and hey presto!

The only thing to be careful of, is I'm not sure if you can adjust it all the way one way untill you take all the freeplay out of the pedal. If you do this then you'll constantly be engaging the thrust bearing, and it'll wear out real quick. Just make sure there's some freeplay in the pedal before it starts to force the master cylinder and you'll be fine.

By adjusting the rod you CAN get SOME extra movement at the bearing. Ideally you want either a smaller bore slave cylinder, or a bigger bore master cylinder, though. The usual reason for this problem is US sourced clutches are VERY oftem based on reground (re-conditioned) pressure plates, that, through geometry changes, alter the bite point of the clutch. If you fit a "new" clutch and the pedal needs altering, or, worse case scenario, cylinders need changing, you can be sure the spec of the cover or plate thicknesses varies from stock, and it's nearly always the cover that has been re-conditioned by surface grinding a used unit. Some are based on patently scrap covers, and fall under "Real-Con Clutches" IMO.

Chris, you have just described EXACTLY what happened with my car after installing a US Southbend clutch and pressure plate. Several garages looked and tried adjusting the clutch pedal, we even replaced the slave cylinder with a spare from a VVTI. The biting point is still 'on the floor' and the pedal still vibrates when released.

I've been advised to buy a new flywheel to solve this.

Yeah mine's quite low now as well, crunches sometimes when trying to change too quickly.

Chris, you have just described EXACTLY what happened with my car after installing a US Southbend clutch and pressure plate. Several garages looked and tried adjusting the clutch pedal, we even replaced the slave cylinder with a spare from a VVTI. The biting point is still 'on the floor' and the pedal still vibrates when released.

I've been advised to buy a new flywheel to solve this.

Opposit to my Southbend mate... My bight was really nice about a month ago.. Something has changed since then and its pretty near to the top of the clutch pedal travel that it bights...

I prefer to get some bight lower down. I blame the cylinder and Its being replaced on thursday, Ill then adjust to make it where I want it.

At least then I know I have not adjusted it to compensate for a failing clutch cylinder..

Tell me if you think Im doing it wrong Chris??

High bite is worse than low bite isn't it? low bite just means you might not get full disengagement, high bite means knackering bits of the drive assembly over time!!

High bite is worse than low bite isn't it? low bite just means you might not get full disengagement, high bite means knackering bits of the drive assembly over time!!

Thats why its being replaced V soon... Its only been apparent recenty...

I find it hard to get in to gear from a stop, so yes Im not sure everything is parting as it should due to a loss of strength in the cylinder and fluid going down in level for the first time in years...

As far as Im concerned Fluid loss in the clutch resevoir can only be due to a F**ed cyliner and leaking fluid or a nearly dead clutch.. And I can see that I have lots of clutch left!

Is only been in 2 1/2 months

Chris, you have just described EXACTLY what happened with my car after installing a US Southbend clutch and pressure plate. Several garages looked and tried adjusting the clutch pedal, we even replaced the slave cylinder with a spare from a VVTI. The biting point is still 'on the floor' and the pedal still vibrates when released.

I've been advised to buy a new flywheel to solve this.

Most unlikely to solve this, the real cure is a new "proper" clutch....

You may need to change both the cylinders, if it's just the slave you should be able to see the fluid leaking under the boot, if it's the master it may not be visible as it could be bleeding back into the reservoir. It's always good practice to chsnge both though.

Sorry for re-igniting a very old thread, but I thought it better than starting a new one

After having the clutch replaced in my old Supra (my uncle now has it) with a stock OEM unit, the biting point is much lower than it was before.

Can this be adjusted as per the above text, more to the point, should it need adjusting if it's been replaced with like for like? If so, is there a pictorial guide anywhere on how to do this?

The biting point is pretty damn low, I wonder if it's not disengaging enough?

Thanks

Are your gears crunching or not changing easily?

Occasionally the odd crunch and seem a bit stiff at times. It never did this at all before the clutch change.

See here:

CLUTCH.pdf

Awesome, just what I was looking for.

Thanks very much Chris