Slave question

[MattPro]

I am about 90% done with my 5-speed swap, I just seem to have run into one problem...

Is the clutch slave supposed to be able to move in/out when out of the car? Before I installed it I tried to check the shaft for in/out movement, and it didn't seem to budge in either direction. I don't know about clutch pneumatics, so I just went with it.

I just bled it, and now it doesn't seem to be engaging. I don't have a selector rod yet, so it's kind of hard to know what gear I'm in but with the clutch down I can't seem to move the output shaft in any direction in any gear.

Any advice is appreciated.

[TurboJake]

I am about 90% done with my 5-speed swap, I just seem to have run into one problem...

Is the clutch slave supposed to be able to move in/out when out of the car? Before I installed it I tried to check the shaft for in/out movement, and it didn't seem to budge in either direction. I don't know about clutch pneumatics, so I just went with it.

I just bled it, and now it doesn't seem to be engaging. I don't have a selector rod yet, so it's kind of hard to know what gear I'm in but with the clutch down I can't seem to move the output shaft in any direction in any gear.

Any advice is appreciated.

Pneumatics is gas, Hydraulics is liquid. The message is still the same, but they are different.

But, yes. The slave cylinder will still be capable of motion when not in the vehicle. It's just a cylinder with a rod, and a seal. Just like a Hydraulic ram you see on many other things, only smaller. Without pressure behind it from the liquid, it's fairly easy to move it. However, if it is a new part, they can be quite difficult to move because of the internals being so fresh.

Because you can't turn the output shaft, either you're not building pressure, or there is no mechanical movement within the bellhousing. So either you have a bad slave, master, or clutch line (Hydraulics). Or the throwout bearing is the wrong size, or the throwout lever is misaligned (Mechanical).

Is the clutch pedal returning to it's position? If so, can you clearly feel the clutch disengagement in it or does it all just feel like much with no defining high pressure point that would indicate the clutch spring resistance?

[MattPro]

Pneumatics is gas, Hydraulics is liquid. The message is still the same, but they are different.

But, yes. The slave cylinder will still be capable of motion when not in the vehicle and is not of any concern. It's just a cylinder with a rod, and a seal. Just like a Hydraulic ram you see on many other things, only smaller. Without pressure behind it from the liquid, it's fairly easy to move it. However, if it is a new part, they can be quite difficult to move because of the internals being so fresh.

Because you can't turn the output shaft, either you're not building pressure, or there is no mechanical movement within the bellhousing. So either you have a bad slave, master, or clutch line. Or the throwout bearing is the wrong size, or the throwout lever is misaligned.

Is the clutch pedal returning to it's position? If so, can you clearly feel the clutch disengagement in it or does it all just feel like much with no defining high pressure point that would indicate the clutch spring resistance?

Thanks, the more you know

Here's all the details:
- New clutch line
- I bought the throwout bearing/lever/clutch/PP/flywheel all from one person, so I'm guessing they are all matched.
- When you push the clutch pedal down it returns to the original location
- When you push the pedal down it feels like a gradual build in pressure, no other feelings at all
- The slave was used and the rod was rock solid. No movement possible whatsoever, I even tried pushing it up against a wall.

Thanks for the quick response, I'm new to manual trans stuff so I have no clue what is normal. I've tried looking around for some info but I couldn't seem to find the normal behavior of the slave when out of the car.

[TurboJake]

Okay, the gradual build up in pressure.

Does it peak, and then get softer as the pedal travels?

[MattPro]

Okay, the gradual build up in pressure.

Does it peak, and then get softer?

Nope, constant pressure increase until the floor. Then it returns probably to about 95% height.

I had straight fluid coming out of the bleeder for probably 10 or 15 engages so I can pretty confidently say there's no air left in the lines.

[TurboJake]

Then it sounds like that there isn't enough throw to fully disengage the clutch to me.

-Could still be air (They can be a pain to bleed fully, they really can)
-Could be the rod is not long enough (Which leads to questions which engine, which tranny? I'm assuming from the 89 in your sig, M20, G260)
-Could still be other factors, but we'll get to those in a little bit.

How are you going about bleeding it? Are you opening, then pushing the pedal, closing, then lifting? OR are you push pedal down, crack bleeder, close bleeder mid stream, lift pedal? The latter will have better success as there is no chance of air bubbles entering the line from the bleeder end.


Also, you could try pulling the slave off without disconnecting the hydraulic lines, and having a helper move the pedal by hand. Expressly tell them NOT to do the full throw of the pedal. Just enough for you to see if the slave is moving in both directions and that the hydraulics seem to be working okay.

[MattPro]

Then it sounds like that there isn't enough throw to fully disengage the clutch to me.

-Could still be air (They can be a pain to bleed fully, they really can)
-Could be the rod is not long enough (Which leads to questions which engine, which tranny? I'm assuming from the 89 in your sig, M20, G260)
-Could still be other factors, but we'll get to those in a little bit.

How are you going about bleeding it? Are you opening, then pushing the pedal, closing, then lifting? OR are you push pedal down, crack bleeder, close bleeder mid stream, lift pedal? The latter will have better success as there is no chance of air bubbles entering the line from the bleeder end.


Also, you could try pulling the slave off, and having a helper move the pedal by hand. Expressly tell them NOT to do the full throw of the pedal. Just enough for you to see if the slave is moving in both directions and that the hydraulics seem to be working okay.

Correct, M20/G260. Slave came from the same trans.

I was afraid to pull it out to test like that, but I'll give it a shot right now. Could I also shove something into the hole where the slave goes to see if I could engage the clutch manually?

I'll try it and a few and report back, thanks again for all the help.

[TurboJake]

Correct, M20/G260. Slave came from the same trans.

I was afraid to pull it out to test like that, but I'll give it a shot right now. Could I also shove something into the hole where the slave goes to see if I could engage the clutch manually?

I'll try it and a few and report back, thanks again for all the help.

Chances are you won't be able to disengage it manually. It takes a LOT of force.

For reference, on a nissan 71C transmission the clutch lever comes out of the bellhousing, and it takes a lot of force with a large crescent wrench to move it. Doing it inside the bellhousing through a hole will be damn near impossible.

You'd basically have to put a pipe in, and use your whole body to try to push it.


But, as for pulling it out and testing it like that, it's not of any real worry. The key is not to allow the rod to be pushed out of the cylinder by moving the pedal too far.

And even if it does, no damage is done. Just needs to be put back together.

[jlevie]

My first suspicion, since you don't mention seeing a leak at the slave cylinder, is that the master cylinder is bad. Since the part is used and was dry for a while that is highly likely. When doing a 5-speed conversion always go with a new master and slave cylinder. And a new clutch, pilot & throwout bearings, and pivot pin.

It is possible that something isn't assembled correctly inside the bell housing, but assume that the problem is with the hydraulics first.

[MattPro]

Just got back from the garage... Pulled the slave and the rubber sleeve thing was wet all around. Had someone push the clutch down slowly... it maybe moved out 1/8" then stopped. Clutch back up, no movement. Clutch back down slowly, nothing. Then I had him push down a little more and it was zero movement until about 75% on the clutch then popped out instantly with fluid squirting everywhere.

My first suspicion, since you don't mention seeing a leak at the slave cylinder, is that the master cylinder is bad. Since the part is used and was dry for a while that is highly likely. When doing a 5-speed conversion always go with a new master and slave cylinder. And a new clutch, pilot & throwout bearings, and pivot pin.

It is possible that something isn't assembled correctly inside the bell housing, but assume that the problem is with the hydraulics first.

It's very possible, they were pulled working but I know they sat around for a while.

And yes I should have gone with new stuff, but sadly the college budget wasn't working out for that. I would order the cylinders now, but I can't wait for the shipping times to get them here. I might just have to find a confirmed working pair local and go with that.