Clutch hits the floor

[MattInAustin]

Truck in question is a '72 F100, 302 converted to 4-speed (T18 I think).

Last month leaving a restaurant I gave the truck a little too much oomph taking off in 1st gear. The clutch instantly hit the floor and there I was, rocketing down a busy street at forty miles an hour locked into first gear. It was quite exhilirating, but I'd rather not do it again. Happy ending: I killed the ignition, coasted into a parking lot and called a wrecker. The next day I see the bar connecting the pedal to the linkage which depresses the lever on the transmission itself had popped loose from its mounting points (this the bar that is mounted to a plate on the frame on one side, and the transmission housing on the other - sorry, don't know what it's called - Z-bar?). So, simple fix, right? But, a little testing in a vacant parking lot with a bucket of hand tools showed that every time I take off quickly this bar pops out, clutch hits the floor, and off I go with the transmission locked in 1st at high speed. I can also feel the gear shift moving to the right whenever I'm taking off in first gear.

The bushings on the clutch bar are certainly worn out, but no way there's enough slop to let the whole piece slip out of position. I inspected the engine mounts and they *seem* okay, but I don't really know what to look for, either. My guess is that at a certain torque the engine moves enough to let that bar slide out from one side of its mount.

Any thoughts on what's wrong here or how to fix it?

Matt

[1972hiboy]

It does sound like its twisting and causing the bar to pop out. id first check the motor and transmission mounts.

[70_F100]

It does sound like its twisting and causing the bar to pop out. id first check the motor and transmission mounts.

Left side motor support.

[72BahamaBlue]

When I used to borrow my friend's bump, I'd carry tools to reinstall that z-bar. Start it while in granny, limp to the side of the road, crawl under...
Bad clutch, squishy motor mounts, manual steering, lots of hills...was a handful for a novice driver.

[Whateverman]

i had a severely thrashed 71 f100 parts truck that got put into daily driver duty for awhile that had a 300/t-18 & used to pop the z-bar fairly regularly (especially if i took corners too quickly) because the cabmounts were pretty much non-existant and all the flopping around would tweak the linkage enough to pop it free ....
- the truck ran great but the body was beyond hope and i didn't want to waste time $$$$ and effort on the truck so i ended up shoving some chunks of 2x4 under the cab and punched some holes in the floor so i could chain the cab to the frame - yeah,it was hokey and probably really unsafe (although i survived) but it cured the problem for the most part

quick temp fix for your problem that will let you diagnose whether or not your engine mounts are soft and thats what is causing you grief (and will buy you time while you wait for new ones to arrive if neccessary): torque chains- bolt a chain(s) between the frame and engine block on whatever side lifts when you punch the throttle (drivers side maybe?? can't remember right now,last time i had to put them on both sides of the block ) ---i usually throw a turnbuckle into the mix so i can get the chain tight

[WoodhouseTruckShop]

I can say with my 68 F100 4x4 both busted motormounts made quite an issue for shifting and the clutch as wel. Easy way to tell is put it granny gear and let go of the clutch almost like your going to pop it. Just jerk it out and right back in at idle. If your driverside mount is busted the tranny will jump to the right and you will probably hear a clunking noise. Use reverse gear to check the passenger side mount.