Clutch Won’t Depress After Master & Slave Replacement

[yacob555]

I replaced both the master and slave cylinders and hooked up the clutch pedal to the master, began to fill up with Dot 4 from the bottom via the slave cylinder and had about of fluid in the reservoir.

The clutch won’t depress and I’m not sure why or how to troubleshoot, would love some tips on where to look if anyone has knowledge of this system.

Thanks!

[uwbuurman]

What is the exact problem? Is it the pedal that won't go? Is is the master cilinder that won't go in or is it the dlave that won't come out?

Check if the slave is mounted the correct way. You can take it of the gearbox with the line still attached, but be carefull, don't step on the pedal, as you will blow out the pin from the slave.

[yacob555]

Thanks for the reply - the problem is that the master cylinder won’t move with pressure either via pedal or by hand. It’s “stuck” with the pedal fully toward the driver. So, the master won’t go in (not sure if it’s because the slave won’t go out).

When installing the slave, the pin did come out of the slave (it had a protective rubber casing that I couldn’t get off without pulling which pulled the pin. I pushed it back into what felt like the correct place). Could this be causing the issue?

When you say make sure the slave is aligned correctly, what am I aligning? Does the pin need aligned with something in the bell housing? Otherwise I’m not sure how I could install it misaligned.

Thanks again

[uwbuurman]

Oh, there is a good chance that you ruined that slave. The plastic cap needs to stay on the pin. Alignment: the pin needs to be on the clutch fork, in the bellhouse. My first suggestion is that the slave is not working properly. Changing it again, I think...

[yacob555]

Oh interesting, the I definitely ruined it if the plastic needs to stay on.

The one I took out had no plastic, it was just a metal pin. Would the plastic on the other one have just worn off?

Thanks!

[Jeroen]

Probably the old cap died of old age, and the new one's now shot too. Luckily these slaves aren't too expensive. Fit the new one with care so it finds the fork correctly (you can pry with a screwdriver beforehand to get a feel). Since both cylinders have been replaced, bleeding the system may be a pita. Make sure to start off with the brake fluid tank filled to max.

[yacob555]

Oh well that’s good news then! Hopefully that’s the issue.

I got a new space cylinder, will try installing tonight. Fingers crossed, thanks!

[yacob555]

Okay so kinda confused on what happened.

I unscrewed the old slave cylinder (but kept the line installed) and the master cylinder depressed as designed.

After installing the new slave cylinder and screwing the top bolt only (lost other one) the master cylinder was still working fine.

I screwed in the bottom screw on the slave cylinder and added some fluid to the slave cylinder via the bleed screw - now the master is not depressing again.

Would love some ideas on the culprit here.

Thanks!

[Jeroen]

Weird! A few things come to mind here:
- pin doesn't position correctly in the dimple of the clutch release fork therefore gets stuck
- incorrect clutch slave, they all look the same but pin lengths vary

[nic65]

the device you see in the photo is held in position with a spring, are you sure it hasn't moved?

[yacob555]

Is the device in that photo inside? I haven’t seen such a thing.

I just uninstalled and reinstalled the slave (and master) and it all seems like the other.

I’m wondering if something inside is wrong? I don’t know what to expect. But can’t really see inside very well.

[yacob555]

[yacob555]

I think that is the edge of the clutch release fork? Should I go in with a screw driver and see if I can depress it manually?

[uwbuurman]

This is the inside of the bellhouse. Leftupper dent in the fork holds the pin of the slave cilinder. As he slave pushes the pin out, it forces the fork to push the bearing in the middle forward, releasing the clutch plate (not on the pic). The other end of the fork is held by a spring, you can see the ends coming out of the holes, opposite side of the bellhouse.

[yacob555]

Really appreciate it!

So, the pin should be pushing on the fork to disengage the transmission to put it into netural, that makes a lot of sense.

What should I be investigating to identify the issue? I'm somewhat unsure how to proceed, but here are my ideas.

1) The fork could be fully engaged without depressing the clutch - would that mean that I should be able to put the car into any gear as it sits?
- Maybe the pin is too long - when I installed the slave, there was resistance for about 3/4 - 1" of install, is that normal?
- It's possible I installed the pin incorrectly or the part is wrong and so the fork is already fully extended at install.

2) Can the fork be broken/immovable? Should I try to move it with a screwdriver to verify it is functional?
- Not sure how that would have happened - and the failure type (immediate pressure loss) doesn't really support that. The line was also bone dry when I changed things (but it had been sitting a while).

3) An issue with the master cylinder?
- It functioned normally without the slave installed in the transmission but hooked up to the fluid line, so I'm assuming it's good but don't know enough to say that for sure.

Thanks!