Engine/Transmission (1998.5 - 2002) Master/slave bleeding.

[Gomez]

I've been bleeding the system all afternoon. I did do a search on bleeding the system and tried almost every tip that I found. I did get air bubbles to rise out of the master cylinder. I disconnected the slave from the bell housing and manually actuated the rod. When the air bubbles would stop, I then reinstalled the slave. No luck, it still would not shift into gear while the motor is running. This is on a new assembly (master and slave and lines). Does anyone have any tips? I think I have a defective part. But the old one did the same thing.



I built a bracket, with a jack bolt, to fit where the slave cylinder bolts to the the bell housing. I snugged the jack bolt to the clutch fork. I then jacked up the rear til the tires cleared the ground. I then tightened the jack bolt against the clutch fork 1/4 " at a time, then put the transmission in 1st gear and tried to turn the rear tire. It took 1 3/8" of travel to disingage the clutch enough to turn the rear tires. Is this normal? The good thing is, is that the transmission is OK, but the problem still remains.



What else can I look for/ or do to solve this problem?

Any help would be appreciated.

thanks...

 

[340Mark]

I'm not sure how much travel there is normally at the slave cylinder, but if the old system did it the problem may be inside the bell housing. How many miles on the clutch and pressure plate? If I get a chance I'll mesure the travel at my slave cylinder, it's on the lift anyway.

 

[cap-n-cray]

Gomez,



What year truck? My 2001. 5 can't be bleed, it is a close system and need to be replaced. The new system was pre-pressurized and once you connected the the slave and the master together it was a done deal.



Cary

 

[SRadke]

24 valve truck? Take it out of the truck totally. Get it all on grade with the slave at the bottom so the air can go up the line without having the high spot on the firewall. Pump the slave by hand several times and the air will go up to the master cylinder. It will get out on it's own from there.

Very easy to do all this, takes about 30 min

-Scott

 

[SRadke]

I'm going to expand on this a bit. The master cylinder will un-pin from the pedal and the safety switch removes from the rod on the inside of the cab.

Then go under the hood, grab the master cylinder. twist it 1/4 turn CCW, and pull it out. Unbolt the slave underneath and lift the whole hydraulic system out of the truck.

Follow the instructions in my previous post then reinstall in the opposite order.

-Scott

 

[MACHINEST]

Here is a fast an easy way to bleed the system,been there done that... Take your master cyl cap off and pull the rubber disk from the bottom of it... . Drill and tap an 1/8 NPT hole in the top of your black cap... put an 1/8 NPT hose barb in it and use a hand vaccum pump,pump up to 25-30 Hg of vaccum on the gage on the hand pump,you will see a lot of air bubbles leave vaccum on til the bubbles are gone... Take hose barb out and install a pipe plug ,install your rubber bladder under the cap and your good to go. .

 

[Gomez]

Thanks for the replies. It's a 2000 with 6 speed. (How do I post a signature?). The clutch was just replaced with a SBC clutch assembly (complete, upgraded to 13 inch), the funny thing was that the transmission was hard to shift before the swap. Thought that the pilot bearing was out. The hydraulic assembly was replaced, but the problem remains. I removed the slave and hand pumped the unit till no bubbles could be seen. I then reinstalled it but it will still not disengage. I did not install the new hydraulic assembly myself (mistake) but had a shop install it for me. Does the plastic holddown for the slave plunger have to be installed still attached? And is it supposed to break off on the first actuation of the clutch pedal?

Just wondering if this may have been a problem.



I'm headed outside to continue bleeding the system. This has to be the problem.

 

[hsmith]

Minimal wear on the release arm and pivot will cause lots of headaches, just like what you are describing. Were these inspected at time of replacing the clutch?

 

[Gomez]

Replaced the release arm. It should some wear.

 

[jkalchik]

Uh, wait a second... ... you removed that plastic ball end from the end of the slave cylinder? I'm pretty sure that's supposed to remain in place, it's a wear part between the piston rod and the clutch arm. As it's got some thickness, it wouldn't surprise me if you don't get full disengagement if it's gone.

 

[MACHINEST]

Uh, wait a second... ... you removed that plastic ball end from the end of the slave cylinder? I'm pretty sure that's supposed to remain in place, it's a wear part between the piston rod and the clutch arm. As it's got some thickness, it wouldn't surprise me if you don't get full disengagement if it's gone.

You are correct the plastic pc should remain on the end of the Slave Plunger

 

[MACHINEST]

Thanks for the replies. It's a 2000 with 6 speed. (How do I post a signature?). The clutch was just replaced with a SBC clutch assembly (complete, upgraded to 13 inch), the funny thing was that the transmission was hard to shift before the swap. Thought that the pilot bearing was out. The hydraulic assembly was replaced, but the problem remains. I removed the slave and hand pumped the unit till no bubbles could be seen. I then reinstalled it but it will still not disengage. I did not install the new hydraulic assembly myself (mistake) but had a shop install it for me. Does the plastic holddown for the slave plunger have to be installed still attached? And is it supposed to break off on the first actuation of the clutch pedal?

Just wondering if this may have been a problem.



I'm headed outside to continue bleeding the system. This has to be the problem.

Gomez,if you work your clutch pedal by hand you should only be able to depress it about 1/4 to 1/2" before you feel the pilot bearing starting to hit the fingers on the pressure plate... . If it more travel you have air in your system... After i bleed my by method above it was better than when it was new,I have about 1/4" of free play in the clutch pedal.

 

[Gomez]

jkalchik. I was talking about the plastic ties that hold the slave rod in for installation. I wasn't there when the mechanic put it in, so I'm wondering if he removed it and the slave plunger came out of the slave cylinder. There is now brake fluid coming out of the slave cylinder, so if it is leaking fluid, then it is possibly sucking air in with each stroke.

 

[GCroyle]

The nylon ball on the push rod needs to be in place. The straps will break from a normal release stroke actuation. If you see intact unbroken straps, VERY doubtful that the system was fully bled, it was just short stroking. The slave can be removed w/o having the straps in place, just be careful. If you tried to test for release with the engine running when you pushed the clutch pedal down to start the engine the piston may have overextended, not sure. When we have done a running engine test w/o the slave installed, someone has to push the slave cylinder in, hold it and provide resistance to the pushrod extending during release stroke. Be careful.



I like both of the suggestions to bleed on bench with pushback and tilting and the vacuum on top of the reservoir is a trick to try, it's actually included in a GM TSB. Just use a trap to prevent fluid from entering your vacuum source.



Good luck.

 

[Gomez]

OK. I'll start in chronological order.



2000, 6 speed. SO.

150000 miles. purchased new in 2000.

Clutch slipped several times while loaded.

Last month transmission became very hard to shift

Thought pilot bearing may be bad.

Good time to replace clutch.

Ordered SBC upgrade to 13 "

Local shop performed installation.

Could not shift into gear.

Shop installed new hydraulic master/slave assembly.

Still, did not shift into gear.

Mechanics say that they did bleed all air out of system.

Shop says that transmission is bad.

I did not believe them.

Drove truck to my house without using the clutch.

performed my own diagnostic.

Bleed system several times. Still would not shift while motor is running.

Fabricated a steel plate with a jack bolt to depress the clutch fork.

Installed in place of slave cylinder

Jacked up rear end till rear tires could be turned by hand.

Ran jack bolt till it was snug against shift fork. I then took a measurement.

We put the transmission in first gear.

While a helper was trying to turn the rear tire, I turned the jack screw, depressing the clutch fork.

It took 1 1/4" inch travel of the jack screw to disingage the clutch enough to turn the tire.

Started the motor and rowed thru all the gears with no problems!

This tells me that the transmission is good!! (great!).

Pulled dust boot off of slave cylinder. Found brake fluid leaking around the slave plunger.

I think this may be the problem.

I called the shop where the installation took place, and they said to bring it back on Monday so they can replace the hydraulic assembly.

This is becoming a PITA! I make about a quarter of my living with this truck. But I still have my old reliable '79 FORD F350 with the 460 ci to fall back on (8 MPG, ouch!). They should still make them like this. Bullet proof. Soon to get a cummins swap! (Hopefully!)

Thanks to everybody that responded.

Go Card's!!!!!

 

[SRadke]

Fluid leaking at the slave cylinder sounds very suspect.

 

[CFast]

so what happened? Did you get it bled? How stupid was the engineer that designed this system without a bleed screw.

 

[TBartlett1]

A bad slave would be an easy fix. Its possible the fork is weak or cracked and flexing. Was the proper throw-out bearing installed?

As far as bleeding it pumping the slave will push the air out the master cyl. I know this works because I repaired a line that was damaged and it bleed out fine, this was on a 2005.

If you pull the boot back can you see inside with a mirror? Does everything look right???

 

[SRadke]

The 24 valves require master cylinder removal for bleeding. There is a high spot in the line that the air will hang up in otherwise.

 

[CFast]

the engineer that designed this system needs a bleeding port in his head. what crap. Dodge let me down, this is just dumb.