Long story short, removed the clutch slave when I pulled my engine out; when I removed it, I left the hydraulic lines connected, thinking I wouldn't have to bleed it when it gets reinstalled.

Now that the motor is back in, after reinstalling the clutch slave, found that when I depress the clutch pedal, it goes down to the floor with almost zero effort, and it doesn't come back up like it should when I release - I have to manually pull the pedal back up. I checked thru the starter motor hole to verify that the slave cylinder rod is making positive contact with the release fork while a helper operated the clutch, and it was - BUT it didn't seem to be pressing with enough force to move the fork all that much.

I'm guessing that I somehow got lots of air in the system, and it needs to be bled out. Anything I'm missing here?

 

Removing the slave cylinder while it was still connected to the hose was a good strategy,
However, it does sound like you got air in the system.

(the best laid plans of mice and men..)

What may have happened is the reservoir may have not been full, and when the slave cylinder extended air was introduced at the master cylinder.

Anyhow, your next step is bleeding the system.

 

Yeah, that's the first thing I thought of, make sure that the clutch slave is engaging the fork. It's easy to re-install it where it doesn't contact the fork. You get about 2 presses of the clutch pedal before the slave ejects it's guts into the bell housing, which is a good time .

Start with bleeding it and see what that gets you. Also possible you have some clutch hydraulics going bad. If so replace EVERYTHING - new master, new slave, and a new stainless braided clutch line.

Dale

 

Yup, sounds like she needs a bleed. Though I did have a clutch master (on an S13) do some funky stuff where it plunged one way but didn't return. Took it to get vacuum bled; no air. Was weird.

 

I think I figured out what happened - rookie FD mistake. When I reinstalled the tranny, the step where you're supposed to ensure the release collar snaps back into the clutch cover was either missed or done improperly. That caused the fork to not be in the proper position relative to the slave's push rod, so there was a bit of slack in the slave cylinder's push rod, even though it was pushing on the fork when you depress the clutch pedal. Good thing for that though, cause it would have been a mess of brake fluid otherwise! With the slave overextending the rod like that it was apparently pulling air in, making my efforts to bleed it futile. I followed the FSM procedure to get the collar re-engaged with the clutch cover, and that plus another clutch bleeding session did the trick.

Pull clutches suck - WTF did Mazda have to make the FD clutch different from push type clutches in almost every other car is beyond me!

 

I have only seen pull clutches on RX7s and Supras. I too would be interested in the why....

But I'm glad to hear that you got this resolved.

p.s. After thinking on this for a minute, maybe having a pull clutch lengthens the effective fulcrum on the pressure plate diaphragm making a heavier clutch feel lighter?

 

That makes a lot of sense, but given enough space in/around the bell housing, you can achieve the same result with a push type clutch by playing with the fulcrum lengths, and/or location of the pivot point on the fork and slave cylinder mounting points. If that's part of the reason why Mazda opted for a pull clutch, I'm thinking available space & packaging was the other reason for the decision.

BTW, since I was concerned I might have buggered up the slave during the 1st attempted bleeding process while the slave was overextending itself, I decided to tear down & rebuild the slave to ensure it wasn't damaged. Basically followed the FSM procedure on that - super easy. Once reassembled, it installed & bled properly with no issues.

 

Sounds like you are in good shape.

The Mitsubishi Evo uses a pull clutch as well, for what it's worth.

I think it supposedly was to make for a shorter bell housing. It's weird but at the end of the day it's not too hard to deal with. Once you understand how it works it's a piece of cake to disengage and re-engage it.

Dale

 

sorry about the quality

 

Ugh, this is exactly what just happened to me this afternoon. FML
Good to find your post to confirm my suspicions of what I'd done wrong though