Can't Get Good Pedal In Clutch

[Ronin 09]

Hello guys

Spent last night trying to bleed the clutch for AGES. It's an early R32GTR with a push clutch.

The best that we could do (sure I am useless by this is with Troy - ylwgtr2 - who knows what he's doing) was to get the pedal to firm up at the bottom 1/4 of the stroke.

The link adjustment in the pedal area are right.

We pulled off and disassembled the master and slave cylinders - the bores all look good, as do the seals. As far as we could we bench tested the cylinders and they both hold good (air) pressure.

What we end up with is the bottom 1/4 of stroke actioning a very small amount of the slave - and with fark all force pushing the pin.

Funny that when we block off the banjo we get a firmer pedal throughout… which leads me to believe it is

1. a farked slave

2. air in the system

However, our testing shows the slave should be OK, and we bled SO MUCH fluid it's not funny. We're talking 1.5L for just the clutch…

Also, cannot be the lines, as there is no leak anywhere. Lines just hold pressure, and are in excellent condition.

New Ogura Racing Twin clutch installed. Note that it will not be the clutch that is the issue as we don't have force at the pin to push the fork.

So, questions -

1. has anyone had this issue, and what did you do to fix it?

2. I remember that bleeding the clutch previously was a bastid… is there a order to bleed and what is it? I think we tried every which way

3. why are we getting good pressure at the bottom 1/4 of the stroke?

4. can it be something to do with the actuator that pushes the master from the pedal?? We measured it and it should be contacting the master cylinder piston just fine.

Any help appreciated, though I've ordered a new master and slave ($$$).

cheers

[blind_elk]

How much freeplay do you have at the fork? Have you observed what is actually happening at the slave when you depress the pedal?

[Ronin 09]

freeplay at the fork is fork all (sorry)

no action at the slave for the first 3/4 of the pedal stroke, then small movement for the last 1/4 pedal stroke - bugger all force exherted by slave though.

[Guilt-Toy]

a good way to bleed these clutch's is to use the gravity feed.. just make sure the master is full and crack open the slave while the clutch pedal is out and let the fliud drain out of the slave for a while.. maybe one or 2 master cyl's full of fluid.

See if this way bleeds it at all?

If you crack the slave and nothing comes out then bleed the other 2 points before trying again.

[Swiper the Fox]

have you used the correct pivot ball or installed a thick washer under the stock one to give you more cylinder travel?

or

try bleeding it upside down with a large syringe and a piece of rubber vaccum hose over the slave nipple...this will push all the air out through the resivoir at the top.

and

have you bled the intermediate block as well?

[Ronin 09]

cracked all bleeders every which way. Used the correct new pivot...

haven't tried the syringe method at the slave nipple - will give it a go.

have bled at hte intermediate block too...

It's such a simple but of hydraulics, can't see why it doesn't work!! My money's now on a farked slave...

thanks for all the replies, keep them coming

[Guilt-Toy]

crack the slave and let the fluid flow at least 2 master cyl's worth then close it before it runs out (dont let it ever run out)

cracked all bleeders every which way. Used the correct new pivot...

haven't tried the syringe method at the slave nipple - will give it a go.

have bled at hte intermediate block too...

It's such a simple but of hydraulics, can't see why it doesn't work!! My money's now on a farked slave...

thanks for all the replies, keep them coming

[shanef]

atleast spend $70 on a braided clutch line to ease yourself of the pain of bleeding the stock km's of hose/line

P.S did you have a twin in it before? if not, how does the height of the surface where the thrust bearing contacts with the pressure plate compare to the old one?

[MANWHORE]

Also, before we go ahead, it was working before you bleed it right? Unless if you've royally busted it when doing the bleed, it shoudl work.

ok, i found something similar when I did a couple clutches last chrissy holidays. I'm guessing that you've got air in your system. Try this please.

put your hand down, and pull your pedal up to the top. press it down again. Then pull it up to the top. do it a couple times, and tell me if it eventually goes back to normal.

[blind_elk]

You might have stated this, but did you bleed the master cylinder? Ordinarily you need to bleed the master cylinder, THEN bleed the rest of the system. You don't rely on the bleeding at the slave to bleed the whole system.

[GTRNUR]

You might have stated this, but did you bleed the master cylinder? Ordinarily you need to bleed the master cylinder, THEN bleed the rest of the system. You don't rely on the bleeding at the slave to bleed the whole system.

At last! Someone that got it right!

If you bleed the slave cylidner you can put 50 litres of fluid through there and it will still not clear the air if there is a bubble at the master cylinder. You should be able to clear the air by just 3 pumps for the master and 3 at the slave.

1. Fill the resivour, and pull the pedal up from the floor.

2. attach a hose the the nipple at the master cylinder, loosen the bleed valve and have someone slowly push the pedal to the floor with their HAND, so the motion is slow. Tighten the nipple, and repeat from 1 another 2 times.

3. Do the same but for the slave end, again 3 times.

Pumping the pedal fast will not help you purge the air properly, nor will litres of fluid. Do it right and provided you have the correct throw out for the clutch installed and it worked properly before as Manwhore suggested well you should be operational.

[Ronin 09]

It's got a braided clutch line on it already. Didn't have a twin in it before, but Troy put in the twin so can't comment on the height of the surface where the thrust bearing contacts with the pressure plate...

Manwhore, it was bone dry before we started bleeding it - has been sitting around without fluids for a while. My money is still on the slave - a brand spanker is going on today. Possibly the slave seals have shrunk back a bit and are now leaking.

pumping the pedal - it doesn't go back to normal - you're asking me to do that to see if we still have are in the lines?

cheers

[Ronin 09]

You might have stated this, but did you bleed the master cylinder? Ordinarily you need to bleed the master cylinder, THEN bleed the rest of the system. You don't rely on the bleeding at the slave to bleed the whole system.

yep thanks we have bled the master first... new slave going on today!

[skylinecouple]

I feel for you buddy,I did mine last night.That master sure holds some air.Large syringe as Paul stated.Works a treat.Air bubbles rise so inject fluid from bottom.

[T04GTR]

still got air in it.

to save you the obviouse headache. you need to bypass the loop thingy. putting it simply you undo the steel pipe from the master and hook it directly to the clutch hose. (delicate bending reqired)

you will have it done in no time:)

[T04GTR]

and if the master is adjusted corectly it shold gravity bleed. (dribble out the slave) iff not back it off abit till it does. dont get impatant and wind in the master for "more stroke" cos it wont work

[Ronin 09]

thanks lads

a new slave and master went on Friday and solved our problems...

don't know which was the culprit, but it's sorted and bled up properly now

[shanef]

good to hear

[mattymagoo22]

yeah I was bleeding mine and my helper (read knob) let it go dry!!!!!! so mad took me an hour to fix it. those extra pipes are the stupidist things ever invented!!!!!! I ended up getting reverse bleeding it up through the slave then bleeding the master then pushing pedal down clamped off line to slave then pulled pedal off the floor with hand and I heard some air rush out then pdal all good.

I've removed the extra piping now and just run the pipe straight into the flex line. gravity bleed soooo easy.

[T04GTR]

yeah. first thing on the list when doing a auto-manal conversion.