Transmission locking?

There's nothing rocket science about connecting the clutch master cylinder to the truck. I guess you could have a situation where the depth of the new clutch master (where the pushrod goes in) is different than on your old one. I've had this happen on a BRAKE master cylinder, and that pushrod needed to be adjusted to match to get a certain amount of play before it touched the master cylinder pushrod. I guess theoretically the pushrod may not be pressing the piston in the clutch master enough, you'll need to check that; do you still have your old one? You can measure the depth of both, even use a screwdriver and mark a line on it with a Sharpie marker. Yes, fluid level in the reservoir should go down with each bleed stroke, to displace that which has been pumped out. And , yes, when working correctly, if the clutch master cylinder internal volume is (for example) 10 ml, then with each full bleed stroke 10 ml should come out the bleed valve and 10 ml should flow from the reservoir into the clutch master cylinder. Could yours be sucking in air, like from a bad gasket between the cylinder and the clutch master? I think if there was a bad seal there though, you'd see it as a leak.

Well I don't see any obvious leaks but in daylight I will look down all the lines and fittings.

I do have the old mastercylinder so I will check the depth of it and the depth of the new one. Hopefullly I can check it with it on the truck.

Any other ideas as to why the fluid level would not go down in the reservoir?

I work tomorrow so I won't get a chance to work on it until wednesday.... But I will let you know.

Thanks,
Zac

(1) either the master cylinder is bad
(2) there is no route for the fluid to go, such as blocked line or blockage in the slave cylinder.

It might be messy, but what happens if you disconnect the line to the slave cylinder, put on a pastic hose, into a jar containing some brake fluid and pump it a few times (you'll need to pull the pedal up by hand)? Does fluid come out the open line? Does reservoir level drop?

Ok, I'll try that tonight and see, for one, what volume is pumping out the end, and two, just see if it is pumping. Before I had the slave cylinder on I just had the new master on I did do that and just stuck the end of the line directly into the jar of fluid and it was pumping some but I was alone so I was just going by the change in the level and also the fluid that was coming out was darker and there was an obvious difference. I think some is puimping so maybe a partial blockage or the master isn't getting a full stroke in. I did pump fluid up the bleeder and out the master cylinder fitting and that did work... So that might show that its not a blockage but I'll check as much as I can tonight as well as for leaks. I'll measure the depth of both cylinders tonight.

Thanks,
Zac

Well I have been working on this for hours and there is no logical reason it is not working. So I pulled the master off again and checked the depth, the other one had been thrown out... So I check the depth and compared it to the rod. I didn't notice that much of a difference. So I tested to see how much fluid was squirting out while just using a screwdriver with it in the vice. I then put it back on and it was once again not squirting any which meant the rod was not pushing it properly. I adjusted the rod and got it squirting out nicely.

I hooked up the entire system again and started bleeding it. This time the fluid was going down in the reservoir and there were bubbles coming out at the bottom. We went through the bleed procedure probably 50 times and on average about every 6 or so times it went down about 1/2" in the reservoir. After all that bleeding nothing was changing in the clutch and the pedal was still sticking down.

We turned to plan b and forced fluid up the line using a pump thru the bleeder. Got some more air out and closed it all back up. This time the clutch was better but not normal yet. I hooked up the regular bleeding method and imediately upon opening the bleeder the system lost ALL pressure and went back tot he way it was before. I then thought about it and figured when the clutch is up the slave should be compressed. So I compressed it by hand and then closed the bleeder. It somewhat worked this time but still not well enough.

One thing I am wondering is, uis there supposed to be a return spring on the slave? And also, what pushes the slave back in? Just the spring? Because it is more or less staying open. Should the paddle on the transmission be normally pushed in or out.

Logically to me the paddle on the tranny should actually be in towards the slave. And it is not, it is staying all the way open....

I checked everytihng for leaks and it all looks ok... Right now I am thinking about that paddle. Is it supposed to provide the pressure to push the slave back in?

I am really lost on this issue now its so simple but just not cooperating.

Any help or insight would be greatly appreciated... Its cold (-16ish) and spending hours on this stupid system is really killing me lol.

Thanks,
Zac

On these trucks it takes everything working right for the clutch pedal to return back. When this happened to me, I called a Mazda factory mechanic in St. Louis who said that was indicative of the clutch master being bad, but suggested I replace both because I had lifetime warranties on both. And that fixed it. You should not need to pump/bleed 50 times, something is wrong.

Should the paddle on the transmission naturally be returning back by it self? What about a return spring? The master cylinder IS pumping but I guess that doesn't mean its working right.

I know the system works only one way (pushing) because the way the slave works it cannot pull as it is not attached to that paddle. So in other words what returns it?

Zac

The clutch pressure plate has springs. Some transmissions, like old VWs, also have a spring on that clutch release bearing operating lever as well.

So if it isn't returning on its own it would be springs I pressume inside the transmission to return the release lever?

I am just thinking about this because the system is working somewhat properly at times but I think even if it were if the release lever were not returning on its own it would still not work right.

Since there is a problem with the hydrualic clutch system still I need to fix that first. I will look over it all again and see if I can see anything that could be wrong if I don't see anything I guess I will try another master cylinder maybe a second slave too.

If anyone has any other ideas let me know..

Thanks again Cusser.

Zac

Well, strangely enough, my truck sat for several days since I last tried bleeding it and on Saturday I went out to pull off the master cylinder because my new master had found its way to the store so I could pick it up. Right before I started pulling it off I figured I'd give it a few pumps just for reference to see how it felt. Well, I pumped it and it seemed normal! Pumped it a bunch and then heard a pop. I went and looked at the slave and it actually wasn't completely bolted tot he tranny, just the bolts were started, so where the rod touches the slave cylinder it just kind of came apart and popped out. So I just bolted that down and tried it and it was back to nothing again. After several pumps it went back to full normal pressure.

I took it out for a drive and it was fine and still is. I have noticed the threshold point on the clutch is different than before but I'll get used to it.

So all in all.... Its done. I am just trying to decide, I didn't really bleed it out since the last time so I would think that there is still air in the system. Should I tempt bleeding it or if it works just leave it alone?

Thanks Cusser for your help solving this problem!

Zac