Am I bleeding the Clutch slave cylinder correctly?

[Pman1961]

I've looked at videos, etc. and for some reason I don't think something is quite right with my clutch slave cylinder after I have bled the system. By the way...this is the last thing to do prior to setting the car back on the ground and driving it as it has been down over nine months swapping motor and tranny. Okay, the following is how my system was bled:

Slave cylinder is not mount to bellhousing but hanging below.

1) Resevoir is full and cap is installed.
2) I'm under the car holding the slave cylinder level or to where bleed valve is at high point. A clear vinyl tube was placed from the bleed valve to an empty whiskey bottle with brake fluid pretty darn full by now.
3) I open bleeder fitting as my buddy pushes clutch to floor and holds.
4) I then press on the push rod of the slave cylinder as far in as possible then tighten valve while in this position.
5) Did this repeatedly until I felt all air was evacuated.

Situation or problem....After I have tighten the bleed valve in its retracted position and released the push rod, the push rod extends back out a half inch or so. Looking into the slave cylinder without the boot on it appears to have maybe a half inch of travel left. I believe it is supposed to have an inch to an inch and a eigth of travel.

Talking with Brent of B2 and visiting the Tremec site there should be like a .030-.080 space between the face of the throw out bearing and the diaphram so that the throw out bearing does not turn all the time thus reducing bearing life.

My question as I've seen in I believe Moss video on how to bleed a hydraulic clutch. Why does the push rod extend partially after I've closed the valve? Do I still have air or am I doing something incorrectly?

Again, thanks in advance.

[Bob In Ct]

I would remove the cap from the resevoir.

Bob

[jhv48]

The slave rod (assuming you have a pusher type slave) will always push against the clutch fork, thus puting pressure on the throwout bearing. There will be NO clearance. That's the way both the slave and throwout bearing are designed.

Easiest way to bleed is to remove the cap on the reservoir and crawl underneath and loosen the bleeder screw. No clutch pushing is necessary. The fluid will travel from the reservoir to the slave due to gravity. Put a pail underneath the slave and refill the reservoir two or three times or until the fluid coming out of the slave is clear. Tighten bleeder, refill reservoir and you're done. Takes about twenty minutes to let gravity do its job.

[Pman1961]

I was wondering if the cap needed to be removed while bleeding. My original slave cylinder setup had no adjustable rod and I assume pressure was on the plate via throw out bearing at all times. I'm trying to follow B2 motorsports recommendation of allowing clearance between the bearing and diaphram to prevent wear. The Moss video I spoke of was not clear about what was going on at the resevoir but when he pressed the push rod in while the valve was open and then tighten...the push rod stayed in the retracted position where as mine extends partially.

[Pman1961]

JHV48...If I gravity bleed the system would you do it with the push rod in its retracted position?

[jhv48]

It doesn't matter where the pushrod is.

Open the valve and let it flow

[Pman1961]

One more question. Could it be a spring behind the piston of the slave cylinder causing it to extend? Seemed to require a substantial amount of force to push it in its fully retracted position. The Moss video may be throwing me off and I'm trying to do as B2 Motorsports suggest. The hydraulic slave cylinder is a Roseland unit by the way and I've placed a call but it was to late to speak to anyone.

[Pman1961]

Okay I lied yet another question. Since this slave cylinder has an adjustable push rod. What would be the method to adjust it if is in fact that the bearing and diaphram make contact at all times?

[CHANMADD]

The rod in the slave should have 1/8th free play and then a light spring to keep them engaged.

[Pman1961]

I've got the light spring setup using some short throttle return springs from the clutch fork to the bracket which supports the slave cylinder. How much throw or movement in the clutch cylinder is required typically to operate the clutch?

[Joey.S]

You may have air trapped in the master cylinder.

You should be reverse bleeding, empty the reservoir and use a pressure bleeder hook it up to the slave cylinder bleeder screw, with the bleeder screw open a little force the fluid in from the slave cylinder into the master cylinder.
This has always worked for me on this type of setup.

[jhv48]

If it's a pusher slave, there is an internal spring that will push the rod firmly against the clutch fork, thus putting pressure on the throwout bearing.

If you want to create space between the slave push rod and the clutch fork, then you will need to change to a puller (wilwood type) slave and mount it to the engine block.

The pusher slave does not need an external return spring (unless you really want to install one). If you are afraid of throwout bearing pressure, then you should change to a puller setup.

The type you have are used on all SPF's and the t/o bearing is meant to have continual pressure on it. Ten million mustangs can't be wrong!

[Pman1961]

Never heard of reverse bleeding but i don't see why it wouldn't work. Another option to try. Back to CHANMADD....this adjustment could be accomplished should a half inch of throw is all that is needed. Unless further bleeding gains additional travel.

[Joey.S]

Originally Posted by Pman1961

Never heard of reverse bleeding but i don't see why it wouldn't work. Another option to try. Back to CHANMADD....this adjustment could be accomplished should a half inch of throw is all that is needed. Unless further bleeding gains additional travel.

Hi,

Trust me I do reverse all the time on fords, Gm's Honda's etc....
it works everytime. It is harder to bleed a clutch system then a regular brake system. You may have air trapped in the master cylinder or the slave. Is the bleeder screw on the slave mounted and pointed at the highest point? Is it level??
It does not take much to have air trapped at the opposite end of the master or slave. You can leave the bleeder screw on the slave open all day and keep topping it up and air will still be left in the slave or master.
You should try and borrow a Phoenix Injecter or somthing similar what it does it forces clean brake fluid from a bottle into the bleeder screw (slave) and pushes everything up into the master. You just have to keep an eye not to over flow the master. I use a Turkey Baster to suck up the fluid. You can google it to see how it works or try you tube.

Good luck and I hope I was some help.

Joe.S

[Jeff Frigo]

Originally Posted by Joey.S

Hi,

Trust me I do reverse all the time on fords, Gm's Honda's etc....
it works everytime. It is harder to bleed a clutch system then a regular brake system. You may have air trapped in the master cylinder or the slave. Is the bleeder screw on the slave mounted and pointed at the highest point? Is it level??
It does not take much to have air trapped at the opposite end of the master or slave. You can leave the bleeder screw on the slave open all day and keep topping it up and air will still be left in the slave or master.
You should try and borrow a Phoenix Injecter or somthing similar what it does it forces clean brake fluid from a bottle into the bleeder screw (slave) and pushes everything up into the master. You just have to keep an eye not to over flow the master. I use a Turkey Baster to suck up the fluid. You can google it to see how it works or try you tube.

Good luck and I hope I was some help.

Joe.S

Thank you, I knew the gravity answer was BS. Ive been wondering if the pressure bleeder would help me. You say it works every time, no mater what? Does it work on the spring loaded cylinders?

[mpanten]

Originally Posted by Jeff Frigo

Thank you, I knew the gravity answer was BS. Ive been wondering if the pressure bleeder would help me. You say it works every time, no mater what? Does it work on the spring loaded cylinders?

It works but I dont think you even need a pressure bleader. By all means get one if you want one beacuse they do work good. I did mine just as they advised in the youtube video i posted and it worked great. A 9 dollar oil can and some hose will get the job done.

[Jeff Frigo]

Originally Posted by mpanten

It works but I dont think you even need a pressure bleader. By all means get one if you want one beacuse they do work good. I did mine just as they advised in the youtube video i posted and it worked great. A 9 dollar oil can and some hose will get the job done.

Im on the way to the hardware store. $9.00 is better than $60.00.

[jhv48]

Pman, if your bleeder valve is on the top of the slave cylinder, like most SPF slaves are, the gravity method works fine. I Do it on mine twice a year and it has been recommended in other threads on this forum. However, if you want to make the job more costly and complicated, then by all means buy the equipment and do reverse bleeding. They all accomplish the same thing.

[Jeff Frigo]

Originally Posted by jhv48

Pman, if your bleeder valve is on the top of the slave cylinder, like most SPF slaves are, the gravity method works fine. I Do it on mine twice a year and it has been recommended in other threads on this forum. However, if you want to make the job more costly and complicated, then by all means buy the equipment and do reverse bleeding. They all accomplish the same thing.

It does NOT work if you have air in the master cylinder, period. Tried it many times, I wish it was that simple.

[Rick Parker]

Are both the master Cylinder and slave new (never installed)? Did you bench bleed the Master Cylinder before installing?

Joey.S has hit the nail on the head. If you did not bench bleed the new master you have air trapped in it.