I had an 87 D150 just like yours. The slave cylinder on mine was at a 90 degree angle to the fork when not depressed, running parallel to the engine/trans centerline. When the clutch is depressed it only moved the slave rod about 1 inch which didn't change the angle too much. If you have binding in the the throwout or pressure plate, the slave bracket will move one way or another. Remember, the clutch pedal is moving about 8 inches for 1 inch of slave travel. Assuming the bore of the slave and master are the same, if you push with 100lbs on the clutch pedal, you are pushing with 800 lbs on the clutch fork. It shouldn't require that much with a stock pressure plate. Try pushing the fork with a prybar, about 2' long should work. If you are pretty strong, you can push the clutch fork by hand. You could always lock some vice grips on the end of the fork to extend it some, then push on them. The extra leverage should allow you to push the fork back. If it won't budge, something is binding in the clutch. It could be a worn fork and ball stud, worn snout over the input shaft the the throwout bearing rides on, etc.

One other question. Do you have the return spring that goes from the fork to the slave cyl. bracket installed? If not, you need it or the fork will fall off the ball stud and you will lose all your leverage.

I hope this helps.....Joel

I took a break from looking at this for a few days to keep my sanity.
I did drive the truck a little around town. Still won't go in reverse without grinding, does pull out of reverse fine with engine on , no grinding. Also noticed 1st gear is mechanically tougher sometimes to engage. All other gears shifted fine.

I will be checking out the things mentioned here later this week. Interesting comments on the slave cylinder mounting as that's really troubling me that my slave rod sits at such an angle. I was thinking the bracket maybe bent but maybe not after reading the post earlier. I don't have any external springs on the clutch fork connecting to the slave mounting bracket? Am I supposed too? Inside the bellhousing I did see the fork ball inside and I believe I remember seeing a return type of spring behind the fork when it was all apart.

I'll try to figure out adding pictures in the meantime as I have a couple of the new cylinder being installed which shows the angle.


Thks

You can find picture posting instructions HERE.

Danny

Update:
We were about to test prying the clutch fork a little more when in first gear with motor running and then shift into reverse to see if it still grinded. That’s when we discovered there was a very small extra push available while pressing the clutch pedal to the floor. I would not consider this normal to push this hard and far to the floor. I certainly did not have to do this before the clutch replacement. Also this last approx. 1/8 inch push didn’t really feel smooth. Well with that little extra push pingo it went it reverse from 1st without grinding! So happy at that for now a drove for a few days and then one time when preparing to go into reverse I pushed really hard on the clutch pedal and it felt kind of funny like something broke in the clutch mechanism. I shut the truck off and climbed underneath for an inspection. Everything looked good and I noticed that the clutch pedal now felt smooth even with the extra push to really bury the clutch pedal to the floor and the truck shifts perfectly smooth including reverse now. Don’t know what happened but for now all seems to be working fine.

Well all good things must come to an end and I’m glad they did as I did not feel comfortable. While driving the truck I slowly lost shifting gears easily including 1st and 2nd not just reverse anymore. Made it home and looked under at the slave cylinder which was dripping brake fluid. Took off the slave cylinder and then removed the slave cylinder bracket. Found the bracket had cracked where the two bolts go thru it to mount off the side of the bell housing. Also the bracket has a whole for slipping over a stud/spacer and then gets tightened down by a nut. That hole/metal tab was also bent. I believe this is the source of my whole problem as the slave cylinder never seemed mounted correctly as I commented earlier when I 1st started the clutch replacement. Unfortunately I didn’t have a good bracket to compare too. I think I overextended the slave cylinder rod with the bracket being bent causing loss of fluid. I looked around the junk yards for another bracket but could not find one. Ended up bending everything back to what I think was normal and welding. The slave rod is now straight out to the fork and no longer at a wicked angle. Shifts nicely all gears including reverse with motor running. Just something that was wrong when I got the truck that didn't show up until new clutch went it. I ordered another slave cylinder but so far it’s not leaking since fixing the bracket.

Thanks again for the inputs - hopefully end of story