• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Clutch slave problem

Will L.

Well-Known Member
Messages
8,070
Likes
7,279
Location
Boulder City Nv
Thread starter #1
nephews 1988 GMC k2500 6.2 with a (smh) manual trans. Yes I like autos. #1 thing I hate about manuals is hydraulic clutches. Sigh...

He has been driving it for a maybe couple thousand miles now since he got the truck. No clutch, trans, transfer case problems at all. Everything feels great.

So he had to replace starter. He Pulled out slave cylinder without undoing hydraulic line. Swapped out starter- I modified the big curved front brace to hold the smaller gear drive. Also- the dust cover where the starter mounts to it was mangled. P.O. cut part of it out. I cut the rest of the trim around starter out so it fits proper now. The rest of it where the clutch slave is looks ok.

Put slave back in and for the starter test-
I told him slowly ease down on clutch pedal and stop if anything felt weird. (Ever get a feeling?). Pedal down just over halfway and he gets a confused look on his face- uh oh. Stepped on pedal a second time and it is like there is a brick under the pedal.
Then we had to stop for the night.

I see an inspection plug on the side of the bellhousing. Iirc that is to align the slave pushrod into the fork dimple. Thinking that was his mistake.

So all you clutch loving folks guide me here please. I know we don’t want to hit pedal with nothing infront of the push rod. Other than that: any tips, anything to watch for?
 

Rockabillyrat

Active Member
Messages
42
Likes
102
Location
Ohio
#6
I've had a few customers trucks do this to me before. Most of the time I can bleed the system and get the pedal back. But I've had to replace the master on a few that never returned pedal operation.

I use a pressure bleeder on brakes/clutches. I found it does a better job in getting the air out. But it's a $400 investment. I've slso had luck with a oiling can full of brake fluid and back filling the system through the bleeder too. Hope this helps.
 

schiker

Well-Known Member
Messages
2,435
Likes
557
Location
Pendleton, SC
#7
So what happens here? Is it The slave extends w/o clutch push back and pulls extra fluid (maybe some air) from master. Then the master pulls more fluid in and there is just too much fluid at full master stroke? Isn’t one purpose of a hydraulic master slave to self adjust travel. Bleeding makes sense.

Worn Master cylinders have failed on me trying to reuse bleeding them once they stroke where they haven’t been stroking. I think they pick up crud from out of normal usage stroke range. Probably related to my poor hydraulic maintenance practices.
 
Messages
5,685
Likes
647
Location
Rural Clifton, Illinois
#8
I've had a few customers trucks do this to me before. Most of the time I can bleed the system and get the pedal back. But I've had to replace the master on a few that never returned pedal operation.

I use a pressure bleeder on brakes/clutches. I found it does a better job in getting the air out. But it's a $400 investment. I've slso had luck with a oiling can full of brake fluid and back filling the system through the bleeder too. Hope this helps.
I did that on the 89 with an electric fuel pump
 

Hink

Active Member
Messages
281
Likes
217
Location
Stevenson, Wa.
#9
Havent been able to touch it yet. This weekend most likely, good thing he can ride to work with a buddy at the moment.
Will, here's an excerpt from a video for the starter install article that I'm finishing up.
In this little cut, I pull the inspection plug and show where the rod needs to seat properly.

I'm sure that is where your issue is, the rod is cocked and wedged.
You may have to reef on it a bit because it may be wedged pretty good, but the whole fix should only take 20 minutes or so. Hopefully he didn't push on the clutch pedal real damn hard and bend the rod. If he did, I'd look into replacing just the rod. I've never done it, but if you can you'd avoid the whole bleeding process which I've never been successful at.

Oh, one other thing... The plug is aluminum and it's likely been in there a while, so use normal precautions to not destroy it, it can round off pretty easily. Kroil, heat, a twelve point socket, and a tender hand would be the ticket here. I'm thinking that other than a junk yard, that plug could be hard to find.
And then I put some anti-seize on it on install for next time.

Video is 54 megs so I couldn't upload here, download from this link should go fast with a normal fast connection.
https://www.dropbox.com/s/5qx776eb7gmh9wf/starter-install-showing-clutch-slave-clip.mp4?dl=0
 

Will L.

Well-Known Member
Messages
8,070
Likes
7,279
Location
Boulder City Nv
Thread starter #10
Hink for the win.
So he didn’t undo the inspection cover on try # 1.
He gets into it 1/2 hour before susnet last night, pulls plug sees the rod against an embossment next to the inspection plug. Lucky guy undoes the 2 mounting bolts, aligns the rod - not bent and more importantly not shot out of the cylinder- bolts it back in and clutch works perfectly!

Then when he tries firing it up we realize he never put thecharger on the batteries from when the bad starter shorted and drained them. Threw on chargerwhile earing dinner, then after dinner she fired up with some coughing.
Next task: seek and destroy air being sucked in. And for those that don’t remember or never saw the old rectangle fuel filters that were on 6.2s- enjoy your ffm. canister has it’s issues but imo is nicer than the can-o-spam.

Thanks everyone, Happy Friday to ya. Don’t forget your green stuff for St. Patrick’s Day tomorrow.
 

Will L.

Well-Known Member
Messages
8,070
Likes
7,279
Location
Boulder City Nv
Thread starter #14
Wonder where the line was drawn. His is GMC K2500.
Factory wiring. I remember changing mechanical lp on several 6.2 but don’t remember details. I know the gassers with mechanic pump havea threaded hole to insert a longer bolt to hold push rod while changing pump and easier install. I could swear some 6.2 had it also. I’m gonna peak at his to see if it has it.
 
Top