I bought a 1988 F-150, 4x4, reg cab, long box, t-18 4 speed manual trans almost 2 years ago now and have been having drive-line problems since i got it. I was leaving the pharmacy one day and got on it kinda hard to cross 3 lanes of traffic and the engine essentially free rev'd as it got over 2200 RPM i assumed the clutch was worn and slipping (truck has 100k and was used as a farm truck last 6 years) i replaced the original 10.5 clutch with an 11" got the bolt kit turned the flywheel new pilot bearing, and release bearing. put it all together and still had the problem. the clutch i replaced didn't seem worn excessively or burnt either..flywheel didn't look abnormal either. i then put a new slave cylinder and clutch master cylinder on it. Also the previous owner had a bungie from the fork going forward to around the motor mount, he said it was just to stop a squeak. Am i supposed to have a clutch return spring from the fork to somewhere? and if so, where would it go? does anyone have any ideas on the free rev or slipping i'm getting. it does it when trying to go up the ridge on the interstate here..I've replaced everything i can think of and am out of ideas...HELP lol

 

Welcome to FTE... and Hello neighbor!!!

Do you have any free travel in the clutch pedal, as in an inch or so slack at the top? It almost sounds like the clutch is not fully engaging..... Summit Ridge on 75 shouldn't be "that" big of a deal, now it you were going north, another story.

 

i have about an inch of free play in the pedal, i have checked it at the fork too when the pedal is let out to make sure there is no pressure on the pressure plate via the fork and it has a very light pressure on it but seems to be just keeping the slack out doesn't seem to push on the pressure plate. going up missionary ridge i'm having to downshift to 3rd doing about 35 and can not give it any throttle without it free reving the engine has the power it just cant transfer it..don't even wanna think about going up white oak mtn

 

You didn't specifically say so but I assume you replaced the pressure plate at the same time as the clutch disk... Right?

You said the flywheel looked good, was it smooth and flat all the way across?

 

yes i did an 11" conversion from 10.5", replaced clutch disc, pressure plate, and bolts at the same time. I also had the flywheel resurfaced at that time from a reputable drive-line shop in town. i tried the slave cylinder at a later time when the clutch kit didn't help..and most recently the clutch master cylinder..which also didn't help..i put a new one piece rear main seal and one piece rubber oil pan gasket in when i did the clutch kit. Felton's said they would test the pressure plate if i pull it, just want to avoid pulling the trans again without being more sure..specially with it having the same symptoms prior to the clutch kit being installed.

 

With it being a Felton clutch I don't think there is any need to pull it.... I've NEVER had a problem with their parts and have installed lots of them, both trucks and construction equipment.

You did remove the bungee didn't you? Was it pulling the clutch fork away from the pressure plate or towards it? I'll bet he was trying to quieten a noisy throw out bearing.......

I'm not trying to run you around in circles, I'm just trying to eliminate the common stuff first.

 

This IS an external slave cylinder isn't it? An internal one can bind on the worn nose of the trans and not move back far enough for full clutch engagement..

 

i agree i worked at kenworth and we got our clutch kits from them and never had any problems, that's why i went there, great guys.. i did remove the bungee, it was acting like a return spring which my truck doesn't have (i am not sure if it is supposed to or not) was pulling the fork forward and thus pulling the bearing away from the pressure plate, i agree with you was probably to quiet the t/o bearing, i replaced it as well when i did the clutch kit..at this point i'll try just about anything..the clutch is the only thing i could think of that wasn't a solid mate..the engine runs great and it drives fine under low load conditions and yes it is an external slave cylinder also got it from felton's the fork seems to travel smoothly i removed the slave and the throwout bearing moves freely

 

I would consider a faulty clutch if not for the fact it is doing exactly the same thing as before the replacement...

There almost HAS to be something binding.... But where is the question....

 

my thoughts exactly..i've replaced every part in the system..the rest of the driveline is hard mated though as far as i can think of anyway i'm lost been working on this off and on for almost a year..they did say the clutch kit is warrantied till the 17th of october but it just seems unlikely especially when going to the heavier duty 11"

 

i looked up the pressure plate torque, but that is about the only other thing that comes to mind

 

As long as it's tight enough not to flop around, it shouldn't cause your problem...

I'll get out of here and give someone a chance at the keyboard, but I'll keep it in mind and try to watch this thread...

 

Thanks White