Hydraulic clutches

[wagonist]

I'm kind of new to the world of hydraulic clutches.
The only 2 cars I've owned with them have been my 2 Caldinas.

Both times, when I replaced the clutch, I suddenly ended up with a pedal that engaged extremely close to the floor, instead of say half way up the pedal travel. For both instances, an uprated (say 30%) clutch was installed.

There is no adjustment on the slave, and I'm not sure what the effect of adjustment is on the pedal itself.

Any suggestions?

[PeteH]

Hi,

Have you bled the system after fitting the new clutch??

Pete

[wagonist]

I discovered later that I could've removed the entire line without disconnecting it

But yes, not only did I bleed it, I did a complete flush through to change the fluid.

[YLD-16L]

Bleed system as Pete noted and then check the pedal free-play is within spec to ensure the master cylinder is being released correctly. I'm not familiar with caldinas but many other toyotas with hydro clutch have a freeplay spec for the clutch fork (if it has one?) so check that too.

If the fluid is right and all specs are within factory adjustment then it's probably due to a change in pressure plate height which you may be able to account for with adjustment of either master cylinder rod length or slave cylinder rod length unless of course they are some other arrangement at the slave end.


Howe low is the pick up anyway? Maybe it's meant to be that low and just feels odd after going from a flogged out worn clutch that had a high take up????

[wagonist]

At the moment I haven't adjusted the pedal (just started driving it again).
From what you are saying, there should be some free play on the top of the pdeal travel?

Also, having issues with the gear selection, ie its very difficult for 1st-3rd, often with a large "snick" as it goes in.
I hate cable shift...

[PeteH]

.
Howe low is the pick up anyway? Maybe it's meant to be that low and just feels odd after going from a flogged out worn clutch that had a high take up????

Hi,

YLD is probably on the money here.

If you're not happy with the take up point I'm fairly certain adjustment will only be able to be made at the master cylinder rod. I'd have a second look at the slave pushrod though, it may have an adjuster.

Edit: your above post suggests that the system may still need bleeding. Perhaps the clutch is still dragging resulting in a tight shift?? Some times it takes alot of pedal pumping to get all of the air out.

Pete

[YLD-16L]

At the moment I haven't adjusted the pedal (just started driving it again).
From what you are saying, there should be some free play on the top of the pdeal travel?

Also, having issues with the gear selection, ie its very difficult for 1st-3rd, often with a large "snick" as it goes in.
I hate cable shift...

In the manuals for old school hydro setups all the ones I have setup have had at least 20 - 40mm free travel at the start of the pedal stroke which essentially equated to 4-9mm freeplay at the outer end of the clutch fork.

I'd find a manual though for yours or similar as the old stuff may be different.

[wagonist]

The clutch fully disengages (which the last one used to not do), but I'll have a go at the pedal adjustment tonight & see what happens.

Cheers for the help.

[takai]

Pedal adjustment for sure.

P.s. just read all of your Excel rally thread, you dont do things the easy way do you

[thechuckster]

Steve, I found that my new Exedy clutch in the GT4 resulted in the clutch pedal having no free travel and the slave piston pusing up firm on the clutch arm - the only adjustment appears to be at the top of the pedal (which I am yet to adjust as I'm lazy).

fwiw: I did have adjustable pushrods on the salve of my RA40 & MA61. Maybe these kinds of rods were eliminated to ensure that the pistons in the slave and master cylinders stayed within an acceptable range of movement?

[wagonist]

Pedal adjustment for sure.

P.s. just read all of your Excel rally thread, you dont do things the easy way do you

Like I said, going to have a go tonight & see what the outcome is.

Why, what's the easy way? Buy someone else's (of which now there's plenty but which all need extra work IMO)? Nothing I've done to that car has been much different to anyone else I've known who's built a proper one (there was one at Bega weekend before last, from Victoria of course, which still had the complete A/C system in place )

[takai]

Like I said, going to have a go tonight & see what the outcome is.

Why, what's the easy way? Buy someone else's (of which now there's plenty but which all need extra work IMO)? Nothing I've done to that car has been much different to anyone else I've known who's built a proper one (there was one at Bega weekend before last, from Victoria of course, which still had the complete A/C system in place )

Nah, i mean with things going wrong, and nasty little surprises (fouling bracketry and such)

[allencr]

Both times, when I replaced the clutch, I suddenly ended up with a pedal that engaged extremely close to the floor, instead of say half way up the pedal travel.

The clutch take up, the distance between being fully disengaged & not dragging and being fully engaged is very little, and should be right near the top of the pedal travel when the clutch disk is decent(not spongy/compressible runout/bent) and the stuff pushing on the pressure plate is decent(not flexing bending compressing air expanding hose).
The pedal can be adjusted for its height/position and for its freeplay, so a lot of travel isn't doing nothing just taking up slack or pushing fluid back into the reservoir.

[wagonist]

takai: you ain't kidding

allencr: I've got no issues with the take up distance, just it's position on the pedal throw.

I half suspect the gear selection issue is either down to a gearbox oil level problem (can't see how as I've put 5.4L in there & with the box supposed to take 5.2 & an allowance for the cooler & lines),
or a damaged gear selector cable (likely as they're a right bastard to feed through the engine bay & I think we've accidentally bent the end of one right over during this process).