Where is the slave cylinder on 1985 300zx - 1985 Nissan 300ZX

Not normally. The clutch slave cylinder is externally mounted. Get one or the tyre chains to change it.

https://www.mycarspecs.com/cost/geo/storm/1992/3-dr/clutch-slave-cylinder-replacement-cost

https://www.google.com/search?q=92+geo+storm+replace+clutch+slave+cylinder

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Try bleed

1. Check the fluid level in the master cylinder. ...
2. Locate the bleed screw on the slave cylinder. ...
3. Attach the hose to the bleed screw. ...
4. Open the bleed screw on the slave cylinder. ...
5. Have a friend press the clutch pedal in and hold it. ...
6. Close the bleed screw. ...
7. Have your friend release the clutch pedal.

Bleeding Clutch by Blocking the Slave Cylinder

Jamie, are you losing any fluid from the clutch master cylinder? By small resistance I presume you mean the pedal feels soft?

If you're losing fluid from the master cylinder you have an obvious leak somewhere and air is getting into the system.

Most leaks occur from the clutch SLAVE cylinder as it does all the work .. If there's no leak from the clutch slave cylinder, suspect the seals inside. It's like a bicycle pump ..the seal inside wears and it won't pump..

You may be able to get an overhaul kit. I'm in the UK .. but here's an Ebay link for a slave cylinder overhaul kit just to show you what it looks like:
FORD CORTINA MK2 CLUTCH SLAVE CYLINDER REPAIR KIT SP2085
Here's a link to show you what the slave cylinder itself may look like (it may NOT be for your vehicle..)
CLUTCH SLAVE CYLINDER FORD FIESTA ESCORT
It's easier and quicker to fit a new slave cylinder than it is to strip down and replace seals with a kit. Be aware, after overhauling or replacing a slave cylinder you have to bleed it - remove the air.

The easiest way of doing this is to make sure the reservoir is fill of fluid, crawl underneath the car with a spanner/wrench, place a rag over the bleed point and get somebody to pump the pedal a couple of times while you undo then tighten the bleed nut.

If it's not the slave cylinder at fault- then it's the master cylinder. Master cylinders also have a 'piston' and rubber seals which wear/perish.
However, it's more than likely that it's the slave cylinder at fault

the main leak will at the slave cylinder past the piston cup
if the slave cylinder is out side the bell housing the simply replace it with new one and bleed out the air
if the slave cylinder is inside the bell housing then unfortunately the gear box has to come out to fit the new slave cylinder

First thing to do is to see if you have a clutch slave cylinder or cable operated clutch. Second the slave cylinder is on the end of the lever that goes into the clutch housing Before you change the clutch make sure that the problem is not in the slave cylinder or clutch master cylinder or cable as the case may be.

on a manual transmission the Clutch Slave Cylinder is located on the drivers side front of the transmission. You can locate it by first finding the clutch master cylinder on the drivers side of the firewall. Then fallow the plastic line to the front of the transmission.

To remove the slave you will first twist it then pull it out of the transmission.

The clutch slave and mater cylinder are replaced as an assembly.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

No, you don't need to replace the clutch itself.
Don't be surprised if the slave cylinder replacement doesn't fix it.
Could be the master cylinder.

The easiest way to deal with this problem is to order the complete preblead slave cylinder kit.
You can, just go with a new slave cylinder but because of the age of the other parts. You may run into other problems down the road. Why have to do it twice.
To replace the slave cylinder only:
Its easy, just carefully push/remove the small metal pin that hold the plastic line to the slave cylinder. then push-in and turn counterclockwise, to remove slave cylinder. Then install new slave cylinder and reverse the procedure. Now bleeding the system will take a while. But all you will do is just keep pumping the clutch pedal until the pedal returns.

Slave cylinder should be on the left side of the bellhousing (follow the line from the clutch master if necessary) If you don't see fluid but you have lost some, also check where the rod from the pedal goes through the firewall to the master...they often leak there and will not drip on the ground.

sounds like you have a air pocket or you fail to engage the slave cylinder push rod If you disconnected the slave cylinder from the hose proceed to bleed out the slave cylinder if you didn't take you slave cylinder and whit out disconnecting the hose and make sure the push rod is against the clutch push arm.