How does this thing work

[kenwheeler]

I've had this truck for 3 months, driven it 3 times and this is the fourth time I've had to drop the tranny. 1st was to replace the clutch, 2nd was to replace the tranny, 3rd was to replace the slave cylinder (yea, could've saved the third time by replacing it on the 1st or 2nd operation) and the fourth is trying to understand this hydraulic clutch. I just can't seem to get any pedal. I tried replacing the master. Removed the master and tried bench bleeding it again. Everytime I reassemble it I lose the pedal. My next plan is to bench bleed the entire system as a unit, master/slave and reinstall everything while its still connected to the tranny. I need some help understanding how the slave cylinder functions.

My guess is that a new release bearing from the parts store or installed on the tranny but outside the vehicle would look like picture A. When you install the trans and bolt it to the engine the release bearing compresses during the install and looks like picture B. When you press on the clutch pedal it extends against the pressure plate fingers and would look like picture A.

Just to try and see what was going on in there, I hooked everything up outside the truck. After I bench bled the system I used a screwdriver to compress the master. It popped the bearing off the plastic holder that the spring wraps around and gushed fluid. I snapped it back on.

Any help with this would be greatly appreciated. I really want to drive my truck.

 

[Spitfire1975]

Gonna ask dumb questions, please don't be offended.

I am assuming you bled the slave when it was all put together?
Did you put the new o-ring in the new slave cylinder?

It's a pretty basic system. There is not that much to it. Bleeding the slave can be a pain from what I have heard, but mine have all been pretty easy.

 

[kenwheeler]

Yes, I bled everything, I ran about 3 quarts of DOT3 through the system trying to get some pedal. Is that how the slave works? Compressing the release bearing when the trans gets bolted to the flywheel.

 

[Spitfire1975]

Yes, pretty sure.

When bleeding the slave did you close the bleeder screw, pump the pedal 15-20 times then open the bleeder to let the pressurized air escape? Or did you do the brake style where you open it as you push the pedal down and close it as you release the pedal?

Could you possibly have gotten a bad slave? What about the o-ring on the slave where the master cylinder line enters? Is it there?

 

[kenwheeler]

The o-ring is there. I did try the press pedal 3/4 to floor, as the bleeder valve was open and close on pedal release. I'll try the 15-20 pump next. I tried alot of other ideas from forum messages but not that one yet. I was just curious as to how that release bearing worked. I thought it would be compressed out of the box and extended when you press on the pedal. But I guess you actually compress it when you install the trans on the engine.

 

[Spitfire1975]

yes. It should not be compressed before installation.

If you don't have a faulty slave, it seems like it has to be a lot of trapped air. The 15-20 pedal pumps has always worked well for me. It has to be done a few times and then I always follow up with the typical brake style bleeding to finish it.

No brake fluid leaking anywhere? (such as in having a cracked master cylinder line that doesn't leak much fluid back can suck in air)

Is it a "new" slave, or a "new-to-you" slave?

 

[kenwheeler]

New slave from Autozone. I did submerge the master to slave fluid line in a wheelbarrow of water. When I pushed on the master with a screwdriver I noticed little tiny air bubbles coming out of the connection. It wasn't many and they were small bubbles. Sometimes it would bubble and sometimes it wouldn't. It didn't happen everytime I compressed the master but it did happen. I didn't think that little bit of air would have any effect. When it bubbled it came out of the connection between A and B where the arrows are pointing.

 

[Spitfire1975]

hmmm. I wouldn't think it should leak ANY air. If there is leakage when not fully installed, what would happen when it is hooked up and pressure is building. I would think a small leak/gap/crack could get large enough to suck air back in. BUT.....I am starting to grasp at straws here.

 

[kenwheeler]

I'm going to replace that line its a dealer part and costs $66. That might be the culprit. I think the problem is when everything is back together, that line might seperate at the connection just enough to cause the air leak. Thanks for the help.

 

[Spitfire1975]

well, if it is all new then it should work.