# Another clutch question!?!



## minitrkingking (May 10, 2009)

I have read most all the threads now it's my turn I guess. 1986 720 lost most clutch pressure (about 2 in" before floor) within 5 miles of driving with no previous problems. I think it's the slave but I want to bleed it first. The pedal hits the floor with no pressure and will not gain any if I pump it and release the valve (either firewall or slave). If I pump the pivot arm in the tranny manually some fluid will come out when I release the valve but no pressure gains. I just need to know how to build pressure with nothing there. Thanks for the help


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## TheRepairMan (Jun 30, 2009)

minitrkingking said:


> I have read most all the threads now it's my turn I guess. 1986 720 lost most clutch pressure (about 2 in" before floor) within 5 miles of driving with no previous problems. I think it's the slave but I want to bleed it first. The pedal hits the floor with no pressure and will not gain any if I pump it and release the valve (either firewall or slave). If I pump the pivot arm in the tranny manually some fluid will come out when I release the valve but no pressure gains. I just need to know how to build pressure with nothing there. Thanks for the help


Are you seeing the Master or the Slave cylinders leaking fluid anywhere?


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## brookwood61 (Aug 18, 2005)

If no fluid is leaking, your clutch master cylinder is probably worn out. Change both it and the slave if you can, it's probably worn too, and may go soon.
Good luck


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## pulsar86 (Aug 13, 2009)

I agree sounds like either clutch master or slave cylinder. You should see a leak somewhere. Have a look on firewall and floor near the clutch pedal. You may get away with just new rubbers if the cylinder is ok. Hope you can solve it easily, best of luck.


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## minitrkingking (May 10, 2009)

I tried a method today of holding down the pedal as I pushed the slave rod and opened the valve. This is the only way we have seen any fluid come out, I have checked for leaks everywhere and nothing. My master is full but I do have a contributing factor perhaps, the previous owner broke the top off the cap and used duct tape to cover it and threaded the remaining portion around that (not the best seal) I can't find one at a junkyard so I may hit up ebay. I plan on replacing both the slave and master probably the slave first but I still have the question of how to get pressure started for bleeding when there isn't any? Is there a specific answer to "that" question? I'm lost here


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## minitrkingking (May 10, 2009)

Oh yeah, will the new cylinders provide the pressure when replaced if they are the problem? Thank you guys so much for the help, I used to own s10s and the forum for them is massive but the people on here are way cooler!


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## brookwood61 (Aug 18, 2005)

If you open the bleeder on the slave, and it drips, your master cylinder doesn't have an air lock because of the tape repair. If you open the slave bleeder, and have someone push the pedal down, and nothing comes out, or it has a weak spray, it is a bad master cylinder.
As far as building pressure to bleed, like brakes do, Clutch systems don't operate the same way. Open the bleeder, and have someone push down the pedal and hold it down. Close the bleeder, and let the pedal up. After a few times with the pedal, take the cap off, open the bleeder, and let it gravity bleed. Just make sure the master stays full.
Good Luck


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## zanegrey (Dec 5, 2005)

to bleed the clutch system you have to have a bottle of brake fluid by the slave.
you put a tube on the bleeder valve of the slave and emerse it in the brake fluid..

you hold the pedal down and loosen the bleeder valve about an 1/8th and then let the pedal up..

this sucks fluid in and lets the air out...
then tighten the bleeder screw..

repeat until pedal is normal...


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## minitrkingking (May 10, 2009)

Thanks for all the input guys, new parts should be here tomorrow so hopefully it'll be roadworthy again! Not having a vehicle for a week is a pain but I actually love working on this thing, the parts are so cheap and pretty simple to deal with now that I know the process.


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## minitrkingking (May 10, 2009)

New slave is on and I'm using zanegrey's method of bleeding, still no pressure. The pedal springs up and goes all the way to the floor. The old slave had fluid in the boot making me think that it is the problem so I didn't get the master. Problem is, I could not find clear tube so I'm using black and can't see what is going on. Can I do this while slave is hanging or does it have to be mounted even? Right now it's mounted thanks a million times people I don't have mechanic money right now


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## zanegrey (Dec 5, 2005)

fill the system as much as you can from the top..

the bleeding method i explained is the final step to getting all the air out..

also sometimes the mc can be damaged by being dry and pumped..

eveything needs to mounted and in place..


maybe try to open the bleeder a little more before releasing the pedal and tighten immediatley after the pedal is released..

also this take 2 people unless you are me...


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## minitrkingking (May 10, 2009)

I have lil bro helping and we're missing a nice 8ft swell from bill this is horrible!!! I will try this right now, thanks zanegrey again. 90 degrees outside isn't helping.


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## minitrkingking (May 10, 2009)

Is it sensible to buy the master kit or just replacing the whole unit? kit $14 mc $24


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## pulsar86 (Aug 13, 2009)

I would go for the new master cylinder.


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## minitrkingking (May 10, 2009)

Okay thought I'd update for anyone who may need this info later. Replaced the clutch master cylinder and slave cylinder, drained all old fluid and started from empty with new dot 3. Biggest tip was not to push the pedal all the way to the floor and open the bleeder valve quickly and close quickly before the pedal hits the floor. Thanks all who helped, trucks been on the road for a week with numerous trips to the beach (50 miles) and just realized today I had an 8mm hanging off the bleeder valve  oops


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## hebrewtigermojo (May 8, 2012)

I try the method zanegrey describes to get the air out, but all the fluid does is drain out. It doesn't suck any fluid up. I still have no pressure. I have replaced both the slave and mc and still no pressure. This is extremely frustrating. Please help!


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## coupeute (Dec 16, 2009)

*Clutch problem*

Did you ever discover if the problem was the slave or master cylinder ?


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