Clutch wont disengage.. Need ideas!!

[MorganRyle]

i recently inherited a 1988 Ford F450 7.3 idi 2 wheel drive. The truck had been sitting anywhere from1 to 2 years. At first it wouldn’t crank at all, so I attempted to roll it off into third gear to pop the clutch only to find that even though you can change from gear to gear and back to neutral the clutch wont disengage. I finally got the truck to crank and as soon as i put the truck in gear it starts moving weather the clutch petal is depressed or not. I Drove it around the pasture for a hour changing gear from 1st to 2nd to 3rd and to neutral. All gears shifted with light force but still no release of the clutch. I am well aware that a clutch replacement is probably in my near further however i would really like to understand why it is forcing the truck to move even with the clutch pedal pressed all the way down. Any advice or ideas will be greatly appreciated.

 

[Jesus Freak]

It's a hydraulic clutch master cylinder, so there's probably air in your system. So it'll release just a little but not enough.

 

[MorganRyle]

Excellent point!! How do you purge the air from the system?

 

[Jesus Freak]

Well, if you feel around on the slave cylinder there's a Allan screw somewhere in a awkward spot, that's your bleeder. When your helper pushes the pedal down to bleed it the clutch won't come back up. So tighten the screw back up and pull the pedal back up. Top off the reservoir and you should be good, if it's just air. It could be bad seals in the master/slave cylinders.

 

[ROCK HARVEY]

I’d also check for play in the linkages between the clutch pedal and the master cylinder. There are bushings in the pedal assembly, and a notorious bushing on the pushrod going into the master cylinder. All these bushings are plastic and likely have play. Look up “heim joint mod” for the one on the master cylinder, that one is a common failure point.

 

[franklin2]

Make sure there is plenty of fluid in the clutch master. Since you are driving it, if it's not completely dry any residual air will work it's way out. If it's a air problem you will not have hardly any resistance when you push the pedal. If you have resistance, it may simply be the clutch disc as rusted to the flywheel. You can usually break them loose by holding down the clutch pedal, and while in a middle gear, say 3rd, keep goosing the throttle and letting up. You are in for a jerky ride, but it might break it loose if it's rusted.

You can also get someone to push the clutch pedal down with the truck off, while you are under there on the driver's side watching the clutch slave move the clutch fork. Very little movement would indicate a loss of fluid/air problem.