Can a Miata clutch slave cylinder fail without leaking?

A little ways back, it was getting difficult to shift my NA Miata into 1st or Reverse, though the difficulty was not always consistent.  Slave cylinder and clutch lines do not appear to be leaking, as fluid level does not seem to be dropping, and there's no telltale stain on the driveway.  So, I assumed internal failure on the clutch master.  I bench bled a new one, installed it, then vacuum bled the whole system.  Seemed like it might have gotten a bit better for a little while, but honestly, I haven't been driving it much.  Now, the problem is definitely back.

So, even though it doesn't appear to be leaking, is it possible the clutch slave cylinder is also failing?  Is there anything else that could explain the problem?  Maybe a DOA clutch master cylinder?  Vacuum bleed not good enough?  Clutch has not been slipping, so I assume there is still enough friction material on it.

It will leak if it fails. Have you squeezed the rubber boot? I've had them hold a lot of fluid before a drip appears.

I like to bleed clutch systems by opening the bleeder, pushing the piston in, put my finger on the bleeder, let the piston return. It will pull fluid into itself. It usually only takes a few pumps to fill the system and send fluid out the bleeder when you push the piston in. Close the bleeder with the piston pushed in and you're done.

We actually had one fail on my son's NA and it wasn't leaking...........or at least not enough to see it.

I had one fail w/out leaking on an NC, but can't remember if it was master or slave. 

Mine failed without leaking. It was going bad at least, I was still able to get the car home.

Yup - had those fail on both my 92 NA and 88 e30 with neither of them showing any obvious outside evidence. Seen a couple people keep them stashed as spares as they seem not to last too long on an NA.

I don't recall the one on my NA8 leaking when it failed me suddenly and at a very inopportune place / time.

Hade one fail without leaking on my XJ. Just wasn't quite releasing the clutch.

Sounds like I'm swapping out the clutch slave when I get the chance.   Actually have had one laying around for a while just in case.

NB, thought it was my slave, might've been, but the master was bad too.

Look front side and backside of firewall to see if you have any leaks.  Just faint enough to leak and peel paint, not obvious enough to notice when looking around.

Easiest car part replacement I've ever done was a Miata clutch master.  Ridiculous.  I would presume the NA set up is the same.

And in stark contrast to the E21 clutch master, which has to be the absolute WORST part I've ever replaced.  I digress...

jgrewe said:

It will leak if it fails. Have you squeezed the rubber boot? I've had them hold a lot of fluid before a drip appears.

I like to bleed clutch systems by opening the bleeder, pushing the piston in, put my finger on the bleeder, let the piston return. It will pull fluid into itself. It usually only takes a few pumps to fill the system and send fluid out the bleeder when you push the piston in. Close the bleeder with the piston pushed in and you're done.

Turns out that was not a good idea for me.  Didn't successfully bleed it, and now my fingertips are in major pain.  Vacuum bleeding was out, too.  Bleeder threads were so E36 M3ty that it was just pulling air past them.  EastsideWife helped with a two person bleed, and it did get some air out, but then also stopped working before the slave cylinder was able to move the clutch fork.  So, some air is still trapped.  Really hoping I didn't screw up when swapping the parts to have had the clutch master get air in it, but I may have, the reservoir was pretty much empty by the time the new clutch slave was on.