While a distributor is on order for my daily, I've been driving my '80 ZX to work for about 2 days, or roughly 10 miles per day. No problems.

 

Yesterday after it sat at work for about 10 hours(only a slight incline parking,not a steep incline), I went to put it in reverse and the clutch pedal stayed at the floor. There was no fluid visible at the filler cap of the slave reservoir. There was also no fluid visible on the ground.

 

I added some brake fluid, worked the clutch a few times and it went back to normal operation. I thought for sure I had a leak somewhere so I brought it home and put it in the garage.

 

When I got home the fluid level was still exactly where I filled it to. So I decided to recreate the scenario. Drove back to work, turned around and brought it back home again, let it sit in the garage for 10 hours.

 

I checked the level again and it is still exactly where I filled it to. No puddles, no visible leaks in the engine bay or along the bottom if the car.

 

The clutch engages fine and doesn't slip under light or heavy load. Any ideas what might of happened?

 

 

 

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Did you see any signs of brake fluid on the ground or anywhere in the engine bay?

I didn't. The ground at work was wet, so it would've been pretty easy to see the fluid on the ground. I have a little power steering fluid leak, and confirmed that I was seeing that as opposed to any other leaks. I've been keeping am eye on that power steering fluid leak for some time, so im able to pinpoint any other leaks.

 

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Edit: I drove the car up on some ramps this morning, got underneath it to search for leaks through the system, and also where the trans mounts to the block. Didn't see anything. I removed the starter and observed the flywheel dry, however aside from totally removing the transmission I can't verify the pistion seal at the throwout arm isn't leaking. But the clutch isn't slipping under light or heavy load.

Look around the firewall where the Clutch Master comes through. Be sure to examine in the passenger compartment as well to see if the fluid came in through there.

It might have been leaking for quite while, a drip at a time, until it finally got empty enough to stop working.  The cylinder with the reservoir is the master cylinder.  The slave cylinder is on the passenger side of the transmission.  The dust boot on the slave cylinder can hold a lot of fluid, and any leaks would show up more in the area under the starter.  If you slide the dust boot off of the slave cylinder a bunch of fluid might squirt/leak out.  There's no clamps it's just a flexible seal that you can peel off by hand.  I had a bad slave cylinder on my 280Z and the boot was full but there was no large leak.

There's a rubber boot on the master cylinder too.  It protrudes in to the cabin, you can see it from inside.  So, like SteveJ says, the fluid can end up inside.

And, the reservoirs can get loose and leak.  Or crack.  The fluid will drop down in to that dirty dusty area under the cylinder in the engine bay.

I see what you guys are saying now. Forgive my ignorance and poor use of terminology. That might explain why there isn't any visible leaks on the ground. I'll get back under it here shortly and take a look. Thanks for the good input.

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You guys were right. There most certainly is a leak at the slave cylinder.

The Volvo should be back on the road tomorrow, so in the meantime I will remove the one from the parts car and check its worth, and if its questionable I'll order one from rock auto. Hopefully its availability is still reasonable.

I'll check the FSM when I get inside to see if there are any additional seals that need replacing along with the slave cylinder.

Thanks for the good lead!

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Check the master cylinder too. Pull the rubber boot off the end down by the pedal and see if it's wet inside. IMO, it would be a good idea to replace both cylinders now. In the past, when I've replaced one, the other cylinder went bad within a few months. They're usually the same age.

Thanks. I have ordered both the slave and the master cylinder. I feel like it makes sense to replace both at the same time.

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That is probably the most prudent course of action. That way you only have to bleed the system once.

I've replaced the slave and master cylinders. The hydraulics are working properly.

 

Sadly, while test driving, I noticed clutch slip at hard throttle. Normal acceleration holds fine. I'm afraid the day I knew was coming was here.

 

No big deal replacing the clutch, but I wanted to ask you guys your thoughts on lightweight flywheels, and whether or not they are a bad idea for a stock L28E like I have.

 

If not, then I would like some recommendations on weight for a stock setup, please.

 

Thanks once again for your time..

 

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Edit: I'm looking at Motorsport's Fidanza 10.7lb flywheel coupled with either an Excedy stage 2 or centerforce stage 2 clutch. Perhaps this is overkill for a stock engine.

 

 

I have a light weight, 10 or 11 pounds, aluminium on my 240.  takes a minute getting used to it but is fine after that.  I really like it.  You may could get your OE one to 15lbs?

I like the the Exedy kit, have it on both my 225mm manual coupes.

https://www.amazon.com/EXEDY-06009-OEM-Replacement-Clutch/dp/B001B5D7TE