95 F-150 351w 5spd 4x4.

Truck is driven on weekends, maybe 15-20 miles per week.

85k original miles.

Every now and then it will act like the clutch isn't engaging. Push the pedal in and go to change gears and it's like you haven't engaged the clutch at all, hard coming out of gear and grinds going in, especially in reverse. Pumping the clutch a few times seems to get it to go into gear.

Will do that a few times and then act normal.

Fluid in clutch reservoir is good, pulled little boot to confirm.

Strange that it just does it every now and then, no consistency to being cold, warm, etc.

Thoughts?

 

Check the firewall for cracking around the clutch master cylinder.

 

Also, have someone push in the clutch while your under the hood, checking for firewall flex.

 

look under the dash at the swing arm that hooks to the cylinder rod. there is a plastic bushing on it that will ware out. after it wares out the cylinder rod will start warring a groove in the swing arm. also make sure the arm is bolted tight to the clutch pedal assembly. You will need a flash light to see up under the dash. another place to check is the slave cylinder push rod bushing under the truck. there is a plastic bushing on the end of the rod where it pushes on the through out bearing fork. make sure it is there.

 

Great tips will check them out and post back.

 

Ok- checked out the bushings/linkage everything looks good, no obvious signs of firewall flexing.

The problem is definitely more common now, almost constant, but if you press the clutch very firmly, almost mash it into the floor it engages ok. There is no slipping on takeoff.

Maybe a pressure plate?

 

if the linkage and bushings all look good then i would think the master cylinder on the firewall or slave cylinder on the bell housing. the master cylinder may be bypassing or have air in the line. i don't think it's a pressure plate issue.

 

Is it getting real cold where you are?
Have you ever flushed the fluid in the system?
Glycol fluid is pretty hygroscopic.
The O-rings get old and brittle.
If there's moisture and it freezes they have a hard time sealing.

 

it's down near 5 at night and in the high teens tomorrow. will be in the 20s for the rest of the week. looking at 1 - 3 inches of snow tonight and tomorrow. i have not flushed one of those cylinders in 15 years. i do know there is a bleeder screw on the slave cylinder.

 

I only ask because it seems every year when it gets real cold the forum sees a bunch of hydraulic clutches that won't release, or bleed down in use.

 

That could very well be, I'll check into it but it was doing this earlier when it was much warmer also.

 

It was the clutch.

Replaced it, pp, pilot bearing and the slave cylinder.

Truck drives a lot better now, thanks for the help in narrowing it down, hate to bite off a project like that without eliminating some variables.