I was driving to work this morning and my hydraulic clutch linkage messed up on the 1999 f-250 super duty 7.3 with zf 6 speed. It acted like any clutch master cylinder when they go out, the pedal went to the floor and the clutch would not release, but it also became very hard to shove in the clutch pedal, so I speed shifted it without the clutch and made it to work. So I figured no big deal I will swap out the clutch master and slave cylinder complete assembly in the parking lot, except I had to get a ride 30 miles to an auto parts store that had it in stock. I changed out the complete assembly and same problem with the new one, extremely hard clutch pedal, so I did not dare to push it anymore and risk damaging the new cylinders, and left the truck at work. I am thinking broken throw out bearing jammed into the clutch, or dislocated throw out arm causing the problem. The clutch disc, pressure plate and single mass flywheel were replaced by the previous owner 3 years and 15,000 miles ago. any suggestions would be greatly appreciated. Thanks, Jim

 

I've seen trucks (not Ford Super Duty) where a clutch spring fell out and jammed behind the pressure plate fingers, causing the symptoms you're describing.

 

Sounds like your clutch fork broke. It's fairly common with the early ZF6 and there is a new version to fix where it breaks. The bad news is you will need to pull the trans back a bit to get the new one in. I'm not too sure you will be able to see it without pulling the trans short of a borrosocope but if you pull out the slave you might get lucky seeing it with a flashlight and mirror.

 

Thanks, guys, I pretty much have decided that I will pull the trans, not looking forward to that job since I don't have a hoist, and I remember how much work it was to pull the zf5 out of my old 89 7.3 IDI many years ago.