Bleeding clutch system

[DanEC]

Aaagghhhh - I hate hydraulic clutch systems. Only one I ever had to work on was a Toyota PU 25 years ago. I can't get this thing to bleed - looking for ideas.

I first tried bleeding it per the manual - at the slave cylinder bleeder and stroking the pedal linkage arm instead of the clutch pedal. No good. I then got the wife to stroke the pedal while I bleed it at the slave bleeder. No good. I then got out a Phoneix injection bleeder and tried injecting it at the slave bleeder valve into the reservoir. No good. I then reversed the Phoneix and tried vacuum bleeding it at the slave bleeder. No good.

Should I take the push rod out before trying to bleed the slave cylinder? I'm not getting much stroke before taking up the play at the throw out bearing.

Also haven't tried bleeding the clutch master cylinder separately.

Any suggestions?

[DonC]

I use a Gunson's EZ Bleed with 5lbs. of air in my portable tank. Attach the inline reservoir to the portable tank and the Brake/Clutch reservoir and just open the bleed screw on the slave cylinder. Whole operation takes about 5 minutes to bleed the master and slave and I don't need anyone else to help me. The inline reservoir holds about 8 oz. of fluid so you never really have to worry about running out of fluid while you're bleeding the system.
DonC

[patrickt]

There's something wrong. Clutch bleeding the ERA cars is quick and easy. Did you have the nose of the car tilted up, and surgical tubing on the bleeder screw of the slave headed toward a bottle or jar that has fluid in it? I've had mine completely apart and then back together with a one-man flushing this way. Of course, I can post a pic, but I don't think that's even warranted here.

[Grubby]

I just rebuilt my clutch master and bled it in 15 minutes with a Mityvac hand pump.

You must be missing something.

It does help to have the nose of the car up.

John

[DanEC]

Nose is jacked up in the air. Hose on the bleeder nipple buried in a jar of brake fluid. Couple loose connections at the start but after tightening them up the system was tight. Most of my cars have had manual clutch linkages - but guys, I've been bleeding brake systems for at least 25 years. I agree - something is wrong.

Are you vacuum bleeding or pressure bleeding from the slave bleeder? Are you leaving the pushrod to the clutch fork in?

[patrickt]

Originally Posted by DanEC

Are you vacuum bleeding or pressure bleeding from the slave bleeder? Are you leaving the pushrod to the clutch fork in?

Yes, don't touch the rod to the fork. Put the surgical tubing on the slave bleeder, put the other end in a jar, crack the bleeder a bit, pump the pedal from inside the car, and the jar should fill up obviously and quickly - the tube will fill as well. If it doesn't do this, there's something wrong.

[DanEC]

Except for the pressure and vacuum bleeding experiment I've mostly tried to bleed it according to the manual - "Work the arm on the clutch pedal shaft (instead of pushing on the clutch pedal itself". Think I'll go back to stroking the pedal.

[patrickt]

Originally Posted by DanEC

Think I'll go back to stroking the pedal.

That's what I do. When you have a nice stream coming out of the tube, filling the jar, and no tiny air bubbles anywhere, then you just adjust the fork nut, as per the manual, and you're done. Now, once in a blue moon you can get an air pocket in the slave cylinder and you can burp it out by pushing the slave's plunger back in manually with your fingers a couple of times. What will tip you off that that's occurring is if you've apparently bled the system well, but you don't get a lot of plunger travel against the fork when you push the pedal after you've closed off the bleeder.

[Gaz64]

Seen this many times with hydraulic clutch systems.

Is the bleed nipple on the slave at the highest point on the cylinder?

[Jaydee]

Is the piston in the master cylinder bottoming out on the circlip. If not, then the port to the reservoir will be blocked by the cup. Occasionally, if the cup has swelled for any reason, it will also block the port.
JD

[Gaz64]

Originally Posted by Jaydee

Is the piston in the master cylinder bottoming out on the circlip. If not, then the port to the reservoir will be blocked by the cup. Occasionally, if the cup has swelled for any reason, it will also block the port.
JD

A very good point.

If the slave won't gravity bleed, this could be the reason.

[RICK LAKE]

DanEC Dan try this way Make sure full of fluid and not air or bubbles.
It's easier if you have the floor out but not required to see this. will need 2 people or a prop rod to hold the pedal down.
Press pedal and hold it. Crack bleeder. Fluid will come out until there is no force from the clutch fork on the slave and stop. You need to manually push the slave piston all the way back into the slave with the pedal on the floor and the bleeder crack. Tighten bleeder and release pedal slow. The fluid will be pulled from the holding tank. 2-3 times of doing this will give you a good pedal. After this, setup the linkage adjuster to the clutch. One side note. Don't mat the pedal to the floor after the bleeding is done. You can over extend the slave and have the fluid leak problem. A small block of wood works great to limit pedal travel. If you have room to see the disengagement of the clutch you want between .35"-.55" clearance of disc and pressure plate for clean release. This also helps get the correct linkage adjustment too. Rick L.

[DanEC]

Originally Posted by Gaz64

Seen this many times with hydraulic clutch systems.

Is the bleed nipple on the slave at the highest point on the cylinder?

Good thought - it rotates but the braided line kind of fixes it in one position typically - I'll double check today. Don't have this issue with brake calipers (or mechanical clutch linkage). May need to loosen the braided hose and readjust.

[DanEC]

Originally Posted by Jaydee

Is the piston in the master cylinder bottoming out on the circlip. If not, then the port to the reservoir will be blocked by the cup. Occasionally, if the cup has swelled for any reason, it will also block the port.
JD

I am getting fluid through the system so I tend to think I don't have this problem. Thinking back I think the cylinder of the slave was rotated where the bleeder was not on top - I'll see when I get back to it today. Also I think trying to bleed it by stroking the slave from the shaft arm instead of the pedal is working against me.

[DanEC]

Rick - I'll put this on my list of things to try if rotating the beeder valve up isn't a cure. I'll also watch the overstroke although with a scattershield it's a little difficult to check by clearance.

Originally Posted by RICK LAKE

DanEC Dan try this way Make sure full of fluid and not air or bubbles.
It's easier if you have the floor out but not required to see this. will need 2 people or a prop rod to hold the pedal down.
Press pedal and hold it. Crack bleeder. Fluid will come out until there is no force from the clutch fork on the slave and stop. You need to manually push the slave piston all the way back into the slave with the pedal on the floor and the bleeder crack. Tighten bleeder and release pedal slow. The fluid will be pulled from the holding tank. 2-3 times of doing this will give you a good pedal. After this, setup the linkage adjuster to the clutch. One side note. Don't mat the pedal to the floor after the bleeding is done. You can over extend the slave and have the fluid leak problem. A small block of wood works great to limit pedal travel. If you have room to see the disengagement of the clutch you want between .35"-.55" clearance of disc and pressure plate for clean release. This also helps get the correct linkage adjustment too. Rick L.

[DanEC]

Thanks all - gives me a few more things to try today.

[DanEC]

Bingo - Bleeder port was turned down. Details, details. Thanks for the tip Gaz64 - I should have been paying attention.

Now - new problem. I have a hard pedal but no stoke. Obviouisly I've got one of the cylinder pistons extended with fluid behind it. I doubt it's the slave cylinder siince I always had the push rod in place - but not sure. So how do I solve this problem in the easiest manner with the least DOT 3 spread around?

Thanks for the help and suggestions.

[patrickt]

Originally Posted by DanEC

- but not sure.

If you have the slave bleeder screw open, and the tube on the bleeder, going in to a jar you can't miss telling that the master cylinder is squirting a nice flow of fluid when someone pumps the pedal. I mean you really can't miss it. It will be as plain and obvious as the nose on your face and that will tell you that the master cylinder is working right. If you can't get that far, then the problem is "upstream" from the slave cylinder.

[DanEC]

Originally Posted by patrickt

If you have the slave bleeder screw open, and the tube on the bleeder, going in to a jar you can't miss telling that the master cylinder is squirting a nice flow of fluid when someone pumps the pedal. I mean you really can't miss it. It will be as plain and obvious as the nose on your face and that will tell you that the master cylinder is working right. If you can't get that far, then the problem is "upstream" from the slave cylinder.

Actually, once I got the bleeder on top I opened it up and it started gravity feeder into the jar (with air) so well that I just short-stroked the clutch pedal shaft lever under the car (per Bob's Manual) and didn't have to touch the pedal. As noted that only took a couple minutes. Maybe I need to crack the bleeder port again and try stroking the pedal now. Holding the pedal down hard, there is still a little free play in the rod so I know it's not in the clutch itself.

[patrickt]

You probably don't need it, but here's a shot of mine for reference. Note that in this shot you can not see the ERA-supplied aluminum spacer between the slave bracket and the block. For perfect alignment, my setup required that.