Master cylinder woes

[91Bear]

Okay, so I went to replace my old rusty MC today. I got the lines taken off, but I couldn't figure out how to get the piston out of the old MC. Can I just pry the boot off and pull the piston out, or do I need to disconnect the piston rod from the brake pedal?

I tried to unbolt the rod from the pedal and the nut is frozen solid. I put so much force on it, I think I rounded the corners with my socket. I didn't think that was possible! It's not like I was using pliers.

I'm beginning to think I should just dip the whole truck in a vat of penetrating oil!

[FORDification]

To remove the master cylinder you do have to disconnect the pushrod at the brake pedal. If you've rounded off the nut, then the nut will have to be replaced anyway, so I'd just go in there with a good pair of ViceGrips and force it off. Good luck!

[91Bear]

The brake light switch is right there next to the bolt and it's difficult to get enough leverage. I would take the switch off, but it is covered in what looks like melted plastic. This must've been worked on at some point, because there are droplets of this same melted plastic stuff on the floor.

[FORDification]

On these old trucks, one repair often leads to another. You just gotta do what ya gotta do to fix it. If the switch has to come out to give you more room, so be it. If it breaks coming out, then replace it. With it being all melted up it's probably on it's way out anyway.

[91Bear]

Well, I got the MC out, but now I can't figure out how to get the shaft out of the old one and installed in the new one.

[68F250]

Your new one didn't come with one in the box?

[91Bear]

OK, well I would say ignore all stupid questions from me in the future, but please don't. I'm so green at this I may injure myself!

(Seriously, I have a Master's degree, it's just that it's not in wrenching!)

[flyboy2610]

That's okay. We all had to go through the learning curve.
And most of us are still on it!

[91Bear]

It turns out that I buggered up the threads removing the bolt, so now it looks like I will need a replacement. Great. Who sells these things?

[FORDification]

Can you just clean up the bolt threads with a tap and die set?

[91Bear]

I guess I gotta go to Harbor Freight again...

[91Bear]

Luckily, the tap and die sets are on sale this week for $10.

By the way, that bolt that holds the master cylinder connecting rod is 3/8" - 16. The threads were salvageable, the nut was not.

[91Bear]

Okay, I'm going to keep posting dumb questions to this thread. I mean, since I am on a roll...

My Chilton's manual shows a bushing that goes around the bolt holding the master cylinder piston rod to the brake pedal. I don't think mine has a bushing there. I want to replace all the bushings (clutch and brake pedals) while I am under there. Can I buy these at an auto parts store, or do I need to get them from Dennis Carpenter or a specialty store like that?

[shrektruck]

NAPA sells em.

[91Bear]

By the way - four years later - that "melted plastic stuff" was epoxy from someone trying to glue the wrong brake light switch onto the brake pedal. It worked...most of the time.

If you do things right the first time, they generally won't have to be redone later!