Problem with hydraulic clutch - Nissan 200SX

Okay, I am not familiar with the Nissan, but the same principle applies to all. It does sound like there is still air in the system.

You may need to rebleed your system. Some systems put the bleed nipples at a slightly lower position than the cylinder when the car is level. You may need to jack one end of the car up higher to compensate for this.

Consider a power bleeder system. They use about 15 lbs. of compressed air to push the fluid out rather than sucking it. When you use a bleeder that sucks fluid like the MightyVac, it will draw air from around the nipple threads and make it impossible to tell if you are done.

Some times the master cylinder fails and debris from that cylinder float down to the slave and cause it to fail. Don't discount that the master is bad if you can't find anything else wrong.

When bleeding the system, replace all of the fluid. Brake fluid is hydroscopic and should be replaced every two or so years.

Check all the lines between the master and slave cylinders as cited by the other poster.

Finally, on all of the Porsches I have owned, bleeding the clutch system is a huge pain. Getting all of the air out is really hard. I usually finish the operation by bleeding manually. Have one person pump the clutch pedal a number of times, then hold it flat on the floor. Open the bleed nipple for a second and then retighten it. Repeat this until you either get the system working or until your helper leaves.

I have found that I had to just stop the bleeding process and button it up, then just drive it for a few days. Eventually the last of the trapped air works its way back up the stream towards the master cylinder and life gets good.

Good luck!!!

I have an 88 pontiac fiero, and with a mid engined car clutch and brake bleeding is a major chore. But, heres some things that work for me:

When bleeding the slave cylinder, make sure the piston is pushed into the cylinder to minimize the chances of trapping air. I bleed my slave by first opening the bleeder valve, then pushing the piston in, then having a friend depress the clutch pedal and hold it, then I close the bleeder valve and release the piston. A block of wood between the piston and the clutch arm usually does the trick, because with the bleeder valve open there is very little pressure on the piston. You may have to do this several times untill you no longer see bubbles coming out. On my car, the bleeder valve is basically the same as the bleeders on my brake calipers, so I was able to put a speed bleeder valve on it and eliminate my need for a friend. Speed bleeders have a spring loaded tip that prevent air from getting sucked in when they are loosened 1/4 turn.

Your master cylinder may need bleeding as well. Some of them do not have bleed valves, which means you'll have to bleed it by loosening up your clutch line and basically repeating the slave cylinder process of opening/closing the line and depressing the clutch. The seals in your master cylinder may be going bad as well.

When bleeding the system make sure you are always topped off on fluid. If you run dry once, you have to start all over again.

Something else you should check: Many cylinders for both clutch and brakes have aluminum housings, and the fittings are usually steel. It is very easy to cross thread them or over tighten them to the point of failure, and you wont always be able to see it from a cursory visual inspection. I would wipe down all the joints to ensure they are clean, then pump the clutch several times, then go back and check all the joints with a clean paper towel. If you see fluid, no matter how little, you've found your leak. Also inspect the flare on the ends of your lines, as any slight deformation will create leaks. I suppose you could put a little machinists blue (or scribble over them with a sharpie marker) and install them, then remove them to verify that the fittings are seating properly. If they are, there should be a clear, even ring around the fitting where the dye/marker was removed. All fittings should be checked, including the bleeder valves (especially the bleeder valves). If you find you have blown the threads somewhere, its time to replace that part. I've seen plenty of guys out there who see a leak and immediately think "Oh, I'll just crank it down and that'll stop the leak" only to have this problem happen.

Avery Montembeault