HELP!! Clutch engagement issue

[Smitty1021]

Trying to be a little urgent about this since I need the truck this upcoming Friday. Although may be a long description, I'll try to include as many details the first time around.

Did a 92' nv4500 swap a couple years back. Everything worked fine except having a tad of an issue getting the truck into 5th gear and 5th gear only. I parked the truck last October to put a LS motor in. It sat outside during the winter and spring until a couple weeks ago. While installing the new motor, I installed a new slave cylinder due to the push rod getting lost on the old slave cylinder. Finally got it running last week. Started breaking the motor in and now at about 225 miles on the motor and slave cylinder (master clutch cylinder and hydraulic line are the old ones), I'm having issues.

This morning on the way to work (about a 15 minute drive), right before I arrived at my shop, the clutch wasn't engaging. I would have to slam my foot through the floor to try and get the clutch to engage. On the way home, same thing except happened sooner. Thinking there's air in the system since I have read these systems are a PITA to bleed, I attempted to bleed the system.

I bled for close to an hour.

I would depress clutch

open bleed screw with pedal depressed

Close bleed screw

Release clutch pedal

Repeat once more

Pop the cap on the master clutch cylinder at firewall and refill with dot 3 brake fluid.

Put cap back on and repeat this process.

Drove truck after doing this process for about 30 minutes. It worked alright at first and as the truck warmed up, it steadily got worse, just like this morning. Not as bad as my ride home from work but still undriveable. Tried bleeding again for another 15-20 minutes, no change. Tried popping the cap off the master cylinder and rapid pump for thirty seconds or so. Not much of a change in clutch pedal feel.

Truck has headers so I'm unsure if heat is an issue. I did not notice any apparent leaks in the system.

Is my bleeding procedure incorrect or should I try another method. All input is helpful and hopefully somebody whom has had a similar problem will chime in. Again sorry for the long post but I'm heading out on Friday for a semi decent drive and obviously can't drive like this. Thanks again

 

[muddtruck]

i bled mine the same way. do you have much pedal play when you first push it?

 

[Justin S]

Might be a bad master

 

[Smitty1021]

i bled mine the same way. do you have much pedal play when you first push it?

0 pedal play. Firm pedal all of the way down.

 

[Smitty1021]

Might be a bad master

That's what I was possibly thinking. Idk what could have happened to it by simply sitting for a year.

 

[Smitty1021]

Update: drove to work this morning. Same thing as yesterday. Towards the end of my trip after the truck was warmed up, I began to have issues with the clutch engaging.

It seems like my grabbing point for the clutch slowly disappears. I can feel the pedal give when the clutch engages but as I get further in my trip, that point where it gives and the clutch engages disappears and it's just solid pedal all the way to the floor with no grab point and no clutch engagement.

 

[Ironhead]

Do you mean "disengagement?" If you have drive, the clutch is engaged. If you have trouble shifting, even with the pedal all the way to the floor, then the clutch is not disengaging. Hydraulic issue is most likely, and like most things, you kind of have to start at the most obvious, and work your way all through the system.

Fluid level, master cylinder, lines, slave cylinder. Is your truck one with the external slave cylinder, or the one with the slave inside the bell housing? Hopefully the outside type, because it should be easier to diagnose and work on.

 

[Smitty1021]

Do you mean "disengagement?" If you have drive, the clutch is engaged. If you have trouble shifting, even with the pedal all the way to the floor, then the clutch is not disengaging. Hydraulic issue is most likely, and like most things, you kind of have to start at the most obvious, and work your way all through the system.

Fluid level, master cylinder, lines, slave cylinder. Is your truck one with the external slave cylinder, or the one with the slave inside the bell housing? Hopefully the outside type, because it should be easier to diagnose and work on.

Your right disengaging sorry. Yeah it's an external slave. I picked up a hand vacuum pump for a brake system and am going to give that a go. If not, I'm probably just going to pick up an entire pre-bled system. Hopefully the vacuum pump does the trick.

 

[Ironhead]

I've had good luck bleeding brakes with my Mitey Vac, so I'm hoping it works out well for you.

 

[Chewy1576]

What transmission was replaced with the NV4500? I swapped an NV4500 in place of an SM465 and retained the SM465 master and slave. I had the same issue, after driving for a while I couldn't get the clutch to fully disengage and it became hard to shift without gears grinding. I put in the correct master and slave for an NV4500 and the issue has gone away. I didn't do a side by side comparison of the slave cylinders or push rods, but I did research and found a difference in bore sizes of master and slave cylinders and I bet the push rods are different lengths also.