bleeding slave cylinder Isuzu 5spd

tucsonsean

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Hi, everybody. Was all set to bleed my clutch slave cylinder ('85 2.5L Isuzu 5spd.), but couldn't find the brass bleeder screw I expected to find. Instead, the slave cylinder has some kind of plastic gizmo with a cap (I'll try to include a picture). What am I missing here?
 
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Couldn't see the pic. Just some sort of error message. I have a great pic of what I'm seeing in my car, but I can't get the site to create the attachment. :mad:I'll try again. At any rate, I've found pictures at other parts' sites, but they always show a brass bleeder. This plastic piece, where the bleeder would be, points away from the ground, toward the engine hood.
 
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No, it doesn't look like the picture, and that's my problem (tho not my only one). I've bled brakes, master cylinders, slave cylinders in the past, always seeing a brass bleed screw. Wouldn't think a plastic one would hold up to brake fluid. Thought the plastic bit was maybe a Fiero thing. (BTW, the plastic cap turns on the plastic riser--I thought about prying it off, but don't want to make things worse. Right now, I have no movement of the cylinder piston when I push in the pedal, so, effectively, no clutch. Ergo, I was trying to bleed it.

Open to any suggestions.
 
To me, the plastic cap looks like a vent. Since the slave cyl doesn't move, why not remove it and trouble shoot from there? Plus, are you sure the line from master to slave is intact, no splits or leaks?
 
Yeah, thanks for the suggestion. I suspect the picture isn't of the clutch slave at all. I think I'll have to pull the air intake hoses and see if I can spot the real thing. Haven't had time to take things apart yet.
 
The picture is not the slave cylinder for the clutch. That is the shift linkage arm. The plastic cap is a bump stop for the shift arm bracket.

You can see the slave cylinder on the left side of the picture. In the picture it goes from bottom to top and you can see the bleeder on the bottom side:
(Left side of picture is firewall side, right side is trunk side)
IMG_2051.jpg



This is the procedure I always use. It is from V8 Archie's website: ( www.v8archie.com )
Clutch bleeding prodeedure
You can do it your way, But this method always works for me.
After checking to be sure there are no leaks in the Clutch Hydraulic system.
Complete ALL of the following steps before test driving the car:
1) Install a helper in the drivers seat to push in and let out the clutch pedal on command.
2) Remove the cover from the Master Cylinder reservoir.
3) Top off fluid in the reservoir.
4) During the course of this procedure DO NOT allow the "helper" to "pump" the pedal. The "helper" is to depress and release the pedal on command only, DO NOT PUMP THE PEDAL. (See theory below)
5) You will be opening and closing the bleed screw on the slave cylinder as instructed below. CAUTION: During this procedure protect your eyes from squirting brake fluid.
6) (Helper) Press clutch pedal in fully and hold.
7) (You) Open the bleed screw to allow fluid to escape.
8) (You) Close bleed screw.
9) (Helper) Release pedal completely
10) (You) Top off fluid in reservoir.
11) Repeat steps #6 thru #10 no less than 5 times before going to #12 below. NO PUMPING!
12) You have now bled the Master Cylinder and the hydraulic line. YOU ARE NOT DONE YET!!!!! We must now bleed the Slave cylinder. (This is what the manual doesn’t tell you)
13) With no further action to be done with the clutch pedal, you can no remove the "helper" from the drivers seat and have him (her/it) help you do the following.
14) After topping off the Master Cylinder, completely remove the bleed screw from the slave cylinder.
15) Have the "helper" stand at the ready with the bleed screw and the appropriate wrench for installing the bleed screw.
16) PROTECT YOUR EYES!
17) With the bleed screw removed. With both hands grab the push rod coming out of the slave cylinder and push it into the slave cylinder as far as it will go AND HOLD it in.
18) Your "helper" will now install and tighten the bleed screw while you hold the plunger in.
19) When bleed screw is tight release the rod and as it comes out guide it into the proper position on the clutch arm.
20) Top off the Reservoir and the job is complete.

Theory:
Why do I insist that you REMOVE the bleed screw when pushing the plunger in on the slave cylinder? This is simple hydraulics. Fluid or air will always go the direction of least resistance. When you are pushing the rod into the slave cylinder you will find that it is impossible to push it in at a slowly and steadily pace. If you push it in too fast with the bleed screw still in and just unscrewed a few turns some of the brake fluid and/or air in the slave cylinder will go back up the hydraulic line that you just bled, thus necessating your starting over.
When bleeding your clutch....The biggest mistake or miss-conception a person can make is to pump the pedal.
The clutch Hyd. system, unlike the brake Hyd. system SHOULD NOT BE PUMPED. The only thing that happens when you "pump" the clutch is that you make any large air bubbles in the hydraulic system into a bunch of small air bubbles. BTW these small air bubbles are harder to bleed out than larger bubbles.
You cannot "pump up" a clutch. If you have to "pump up" the clutch to make a shift then you have a leak and you can bleed the system a dozen times to no avail.
On the clutch, think about it now, if you could "pump-up" the clutch wouldn't the T.O. Bearing tend to invert the clutch diaphragm and travel toward the engine until it met up with something solid like the flywheel. On a braking system, when you "pump-up" the brakes you force the brake pads into the rotor until the line pressure builds up enough that the resistance you feel when pumping the pedal increases. Further, as you press harder and harder on the brake pedal the pads just increase their pressure on the rotors.
GM Thought this through when they designed the system. To avoid "pumping up" the clutch hyd. system, GM put in a small bleed back hole in the master cylinder. (BTW not an original idea, all Hyd. clutches have it) This bleed back hole relieves line pressure every time the pedal is at the top of the stroke. Didn't you notice when you "pumped up" the clutch pedal that it doesn’t firm-up like the brake pedal does?
The only thing you accomplish when "pumping up" the clutch pedal is to take any air bubbles that are in the system and atomize them into smaller air bubbles, thus making the problem worse. Remember when you were at the soda shop, as a kid, and your parents kept giving you hell about playing with you soda and straw? Same theory here! The more you move that soda through the straw the smaller the air bubbles become.
BTW the "hand pumps" work ok but I’ve never needed to buy one yet. With the hand pumps you still need to ensure that the slave cylinder gets completely bled.
v8archie
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Thanks everyone--and, as usual, Oreif saved the day with his pic and description. My helper's my wife, and she's nervous about getting the bleed screw back in, so I may have to figure out how to do it alone. But it'll get done, and it's my last task before taking it through emissions. (Any suggestions for increasing my odds there?):)
 
Thanks everyone--and, as usual, Oreif saved the day with his pic and description. My helper's my wife, and she's nervous about getting the bleed screw back in, so I may have to figure out how to do it alone. But it'll get done, and it's my last task before taking it through emissions. (Any suggestions for increasing my odds there?):)

To pass emission testing, Make sure there are no vacuum leaks especially with the EGR, Fill up with premium gasoline, Especially Mobil, shell, or BP. These have additives that burn a little cleaner. Also make sure the car is fully warmed up and if possible take a short run down a highway.
If you do fail, Get a print-out of the testing and post the results. We can assist you as to what is causing the high readings depending on which reading fails and by how much.

You can have her push the rod back in. It is not hard to do with the bleeder off.
 
ok i got a question, i have followed these steps to a T and every time i bleed the salve cylinder by pushing the rod in after tightening the screw i let off the rod and somehow it sucks air back in. both slave an master cylinder were leaking before and replaced... maybe a line is going bad? i cant see any visible leaks but what looks like a build up of grease on the bradded section of line by the slave... and im only getting about 9/16 inch of rod travel
 
Just an update: I replaced my banjo rod and slave cylinder with parts from Rodney, and found a like new (!) clutch pedal in a salvage yard. We bled it about 6 times (the slave about 8), and I now have an inch or more of movement at the slave cylinder. It goes into all gears, hot or cold. Thanks everyone.

On to other problems, er, challenges!
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