I have a 99 maxima with the 5 speed MT. I have had the problems in the past of the Clutch Master Cylinder Reservoir being drained down and having no clutch. At the beginning of this week I started to notice that my clutch was slipping. I would be in 3 or 4 gear and if I would accelerate hard(with out my foot on the clutch), you could see the RPMs go up and then slowly come back down to the RPM of transmission and then it would hook up with the transmission completely. Yesterday, I was driving normal, and the clutch when down to the floor and would barely disengage the clutch. It had the distinct aroma of burnt clutch. As far as I can tell, with the clutch pedal in the engaged position (all the way towards me) it would barely grab the clutch, and there is a slight vibration in the whole car. With the clutch pedal all the way to the floor it disengages a little more, but when you start the car it will move the the car forward ever so slightly.

I got it home today, I removed and disassembled the clutch slave cylinder(the one just below the front valve cover) and also removed and inspected the hydraulic line from the slave to the 1" square box where the other hydraulic line comes from the Master Cylinder. I am a Hydraulic student so this style of set up is not alien to me. The slave cylinder after disassembly looks to be in working order, the seals are plyable and not cracked. The Copper piston looks to have normal wear on it(for a 7 year old car), the pin looks to have normal wear on it also. The hydraulic line did have some small holes in it on the slave cylinder crimp connection. I placed a rubber hose over the holes and tighted a hose clamp down onto it, to see if i can get some better pressure. I removed and disassembled the Clutch Master Cylinder and inspected all parts, everything looks to be normal and almost no wear and tear in the Master cylinder.

Once I got everything back together and reinstalled on my car I have tried bleeding to no avail. I bleed the bottom valve into a half full can of clean brake fluid first. Once there are no bubbles coming out of the lower bleeder valve I move to the top bleeder valve. And repeat bleeding till I get no more air bubbles out of the top bleeder valve. It still goes down to the floor before it starts to disengaged and it still burns the clutch on the flywheel being as it didn't fully disengage.

I am trying to figure out if my pressure plate has gone the way of the dinosaurs or not. I would like to know if the clutch fork is supposed to(without your foot on the pedal) retract as far back as it can and fully compress the piston on the slave cylinder. Because when I have someone press on the clutch pedal and release it i can physically move the clutch fork towards the slave cylinder a good 5/8 -7/8 of an inch more. Do you think the tines on my pressure plate have worn through and are not forcing the slave cylinder all the way back or do you think its just that hose? Any Help you can provide me and links are very much apprieciated. Sorry for the long post.

MadMaxima - Mike

 

Replace the hose, bleed the system with a power bleeder.
Once you have master/slave pressure you can determine wheather or not the clutch is bad. From what your describing, accelerating, RPMs going up faster then your car takes off, you clutch is slipping and needs to be replaced.