It sounds like an air in the hydraulics issue. If you can figure a way to pressure bleed the system from the bottom up it is easier to get trapped air out than trying to foot bleed from the top down. I made a pressure bleed tank from pvc and some fittings that works well. I use it on brakes and clutch systems.

 

the way the slave/master cylinders on these trucks are set up they come new as a sealed unit so i would think if it had air in it, you would probably see a leak somewhere. unless the guy at the shop took the two 13mm nuts off the studs and removed the slave cylinder from the bellhousing then there is no way he could see the rod, even then when you do remove it the rod can just fall out, and i wouldnt suggest pushing the clutch without the slave cylinder being bolted up correctly. now that we know more about the problem i would start with another set of master/slave cylinders since it only takes about 15min to change them out and if thats not the problem its not a bad idea to replace them with a new clutch anyways. if the cylinders dont fix the problem then your going to have to pull the transmission and inspect all of the parts of the clutch system. it could be the throw out bearing, or could be wear on the pivot fork, or even a problem with the pressure plate like on of the pivots inside it being broke. i have seen all of these things cause the problem you are having. when inspecting all of the parts keep in mind that it only takes as much as .025" of wear to cause the clutch to not release

 

Ok, had the m/s replaced w a valair. Same problem, needs new clutch. Now, the guy I talked to where I bought the part said ceramics weren't good to slip the clutch. True? Did I waist money replacing the master?

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Valair has a 12 rated 300 hp 700 ft pounds 3400 pressure plate $280. Organic facings.

 

i've never had any problem with a ceramic clutch

 

The ceramic is one of the toughest materials out there, the negative about them is that they catch hard, meaning they don't engage as smoothly as other materials.

 

A ceramic clutch is either engaged or disengaged. It does not slip.

Luke

 

they do not feel like an organic clutch no, but i wouldnt say they are in or out, try a con-fe feramic clutch now that is in or out but the sacs clutch that i'm talking about is not. they use what looks exactly like the disks that SB uses in their ceramic 12cb dual disk's (which i tow with on a weekly basis) and for the holding capacity they engage plenty easy. I have never had a problem towing with these clutch's even backing up loaded has never been a problem.

 

Ceramic's are a NO SLIP clutch, unless its a multi disc, and still it is limited slip and we do not recommend them for towing. If you have enough power to just let out on the clutch and go, then you will be fine. Most dont. You can also underpower a clutch. Forcing a ceramic clutch to slip when it is not designed for that will burn it up. Some people do use them for that, most wont have good luck. JMO

This is also why they engage so quick, if they had slip in them they wouldnt