I've got an 87 f150 4 speed. Will it hurt the transmission. If I go a model year later with the slave and master cylinders for the clutch? The hydraulic line for that year was only produced that year and I can't find one anywhere so the easiest option right now is to just go up a year with slave master and hydraulic line. Will that damage the transmission?

 

If the master and slave piston bore sizes are the same and what you are replacing, it shouldn't hurt anything.

 

The Master Cylinder shouldn't matter the slave is the key. Does it mount outside of the tranny or do you have to drop the transmission? If it mounts to the side like my '92 you shouldn't have a problem at all. The piston sets in a cup so the bore size of the piston doesn't matter. (FYI, just don't cut the plastic strap on the Slave cylinder before you get it installed)

 

Matching the master and slave bore sizes does matter. Later models use a smaller master cylinder bore, but '88 should be the same as '87. Still doesn't hurt to double check so there are no surprises.