Hey everyone- recently picked up the above referenced truck, seems to run OK, I have to do the throttle cable hack still to get full travel back, but the issue is with the clutch. I know the master and slave cyl. on this truck were replaced, the new slave cyl. is the style with the boot and blue plastic behind the throwout bearing.

The clutch works fine, releases fully, no issues getting into gear at all. Watching the throw through the access window, looks like I have a good 1/2" or better of movement, that should be plenty to disengage the pressure plate, and it seems to be doing so, no drag at all with the pedal all the way down. The issue is how close to the floor it is. It sits about even with the brake pedal, resting against the master cyl. piston. I can pull it back toward the seat a distance equal to the travel from where it rests to the floor. Is there supposed to be a spring or something to keep it from flopping around? The bracket the pedals hang from is in fine shape, no wear.

Also, the interlock switch works, I gotta step on the clutch to start it or get it to go into 4wd(electric transfer case with manual hubs), but the switch slides up and down the shaft an inch or 2. Does this have something to do with the lack of free play before the pushrod starts to push the master cyl.piston?

I'd actually like to do away with the interlock switch, is it as simple as just jumping the circuits closed to keep the computer happy? Or can I just disconnect it and still be OK? Don't ask me why I want to disconnect it, I'm old and crotchety and like things the way I like 'em, and I like not having to push the clutch in to start a vehicle. Back in my day folks were smart enough to start their stuff with driving over the neighbors kid!(That's a joke, so no one gets offended or anything)

These symptoms don't seem consistent with air in the system, I can't "pump up" the clutch like you would a brake system with air in it, but it seems from my research that air gets blamed for all sorts of issues with the clutch setup on these trucks, maybe due to the P.I.T.A. factor of trying to bleed it in the truck-seems like that is a crap shoot at best. Would pulling the master cyl and bleeding it get me any more pedal? The aftermarket service books do not address the factory pedal height, so I don't know if it is just supposed to be as low as it is, or if it is out of whack somehow.

Be nice to get the engagement up a little higher than an inch off the floor.
Thanks in advance for any insights.
Pat D.

 

Hmmmm ...perhaps I should re-phrase the question. Let me ask this then- how far off the floor should the clutch pedal typically rest, and how far off the floor should it start to engage upon release? And is there any way to raise the pedal off the floor without installing a longer pushrod? If not, do I need to fabricate a longer pushrod, or is there one commercially available?
Thanks again,
Pat D.

 

The clutch is self adjusting like front disc brakes. If theres no air in the system i have no idea what the problem could be.

When i replaced the clutch on my 87 I could'nt get all the air out of the damn thing. Took it to a local mom & pop shop & paid them 30 bucks to bleed it. Best 30 bucks i could have spent.

On my 87 the pedal goes to the floor & starts to engage approx 3 inches off the floor. Release the pedal & there is almost no free play.

 

I know this is an old thread, but maybe it will help someone else. You would need your clutch switch if you have cruise control. It will disengage the CC when you push the pedal so you wouldn't get that high rev from releasing the clutch.

 

If your clutch pedal is close to half way to the floor I would bet you have air trapped in the
clutch master cylinder ...Air trapped here is a pain in the but,,,i had to remove mine again after replacing it and bench bleed it,,,( watched you tube video for bench bleeding) should have watched video first !!!! You might try removing the line from trans and have a buddy pump up the pedal and use a small screwdriver to press the checkball,,,this will blow fluid and trapped air out but is not the proper way to bleed it,,,but it worked for me when everything else did not !!!

 

Spooktn, I agree, the master cylinder is about as big a P.I.T.A. job as you will find. I also watched a few of those videos on You Tube. The best I got mine to bleed was hanging the whole mess up like they said, with the cylinder pointing in a direction where the air would be forced out, then submerging the lower end of the hose into clean brake fluid. On the opposite end I had a vacuum pump attached, to draw the fluid upward. Once I got some vacuum stored up in the hand pumped canister, I used a hooked wire to push in the check valve on the low end of the tubing that was in the brake fluid, letting the vacuum draw it and the air upward and out of the tubing. Yes, I almost needed more hands for that. At least with this method, the air is going upward, as it would do naturally. The MC was totally full of fluid, you couldn't push the piston in more than 1mm if that.

Another tip I would give everyone is to change the fluid in the whole system like once a year; mine had water and gunk in it that ruined the slave cylinder seal. I have some good Dot 4 that I use that is supposed to absorb less water, and therefore work better and last longer. I have put it into all my motorcycle brake systems and it performs great!