Hi everyone,

New to the forums. Truck in question is a 1981 F150 Ranger SC/SB, straight 6, manual 4-speed.

I keep breaking the pivot bolt on the block just in front of the bellhousing. The first time it happened, the clutch went to the floor and didn't come back - bolt sheared off. My mechanic was unable to find the exact bolt for an 81, but was able to source a similar (I believe one generation/a few years newer) bolt that looked the same except the smooth end where the bell crank pivots was slightly shorter. Drove fine for 2 days, clutch pedal started binding/sticking, looked under the hood and it looked like the bolt was bending/getting ready to break again. With some guidance from the forums, we decided to replace the old crusty engine mounts. Also discovered a lot of wear in the linkage under the dash. Replaced the flat bar, rebuilt the end of the rod with weld (apparently couldn't find it) and replaced the pivot again. Drove GREAT for 2 days, pedal started binding/sticking again.

Anyone have any ideas? What am I missing? Could the slightly shorter pivot bolt be causing all of this just because it's shorter/from a different year?

Pictures attached of the damaged under-dash linkage and the rebuilt rod.

Damaged linkage under dash (flat bar was replaceable, rod had to be rebuilt)

Rod after being rebuilt with weld/ground smooth

 

I'm not sure which bolt you're talking about. Post pics of it. The only pivot bolt that could shear is the one in the BLOCK just forward of the bellhousing. But the hydraulic linkage uses no such bolt. The only pivot bolt on the bellhousing is inside where the release lever (clutch fork) pivots, but it can't shear - it's in compression. And I think it's identical for mechanical & hydraulic. Look at 7B602 in this diagram:

(phone app link)


But ultimately: the short answer is CONVERT TO HYDRAULIC. It's worth the effort & cost. Start with this caption, and continue reading the NEXT until you've seen the whole photo album:

(phone app link)

 

Thanks! I may have been unclear in the original post- the truck is an 81, with a mechanical clutch linkage. You're right, the pivot I'm asking about is in the block, not the bellhousing. The hydraulic conversion is probably not on the table financially, but it's something to think about. I'll try to grab pictures of the bolt this evening.

 

I'm wondering if maybe the throwout bearing isn't binding on the sleeve on the front of the transmission that it slides on. That would cause the problems you're having. If this is your problem, you may be able to get some lube in there from underneath through the clutch cover. The real fix would be pull the transmission and properly install the throwout bearing with grease inside.

This may not be your problem at all. But I had similar experiences with some old Chevy trucks.

 

There should be no grease in the bellhousing. The throwout bearing is installed dry.

 

Sounds like the throw out bearing is sticking on the input shaft or out of adjustment. I use a spring that has 30 lbs of pull. And have never broke anything other then the throw out bearing. Also uou got make sure once you bolt the pivot down its tight and flush. Make sure the fork moves back and forth smoothly.

Although the throw out bearing is a greaseless install. I always use graphite grease on the input shaft for lube and it doesnt get hard.