Can anyone offer help? I am trying to rebuild a 51' f-3 master cylinder. I have okay shop experience but feel I am doing something wrong here. Cylinder was bone dry upon removal and I have cleaned it and the guts and put back together. All I get out of it is air. The fluid can't get past the piston to be forced out. When I remove the clip and let piston forward some, fluid can get behind the piston and then be plunged out, but not when fully assembled. Is this a assembly problem, master cylinder problem or am I missing something simple. I see two holes that are clean, but they also let fluid fill up behind piston, not in front where it needs to be. Does anyone have a solution or good picture of the way it is supposed to be put back together? i replaced all the same way it came out, Going from brake switch to boot-round like screen-spring-flat round metal on top of spring-rubber boot(which way?)-piston, one end has holes, the other a rubber seal, -washer (rubbertype)-large metal washer-clip -boot- plumger. I can't for the life of me figure it out all day. Any help most appreciated. Rob

 

Did you get a rebuild kit or are you just using the old parts that you've cleaned up? If it is the latter, using the old parts cleaned up, that could be the problem. The old parts tend to shrink over the years. I have a '55 f-250 and got a rebuild kit from a local parts store, probably Advance auto (can't 100% remember, but there are only a couple of places I buy parts locally). Once you have the rebuild kit, get a small hone and hone the master cylinder and when putting it back together, "lube the parts in fresh brake fluid. Bench blead and reinstall on the truck. I did this and my truck stops. I must admit it doesn't feel like my newer vehicles, but I have pretty good pedal and she stops everytime (knock on wood). Try that and see what happens. The rebuild kit was about $10- $20 I think. It's well worth the investment. The hone was probably around $10. You need to hone the cylinder because over the years, these things get ridges and grooves worn in them. Hope this helps!

 

Rob

fowl1 is right you should get a rebuild kit. napa should have it. since your cly. was dry it may be pitted. if it's pitted you can't hone it.

 

A rebuild kit is definitely the way to go as the guys said. This illustration might help as well.

Couldn't find your F-3 (catalog code Y) illustration directly, but the master cylinder part number is the same as the one in this illustration.

 

Well, if it were me, I'd replace the master cylinder with a new one, not a rebuilt one. And I would not rebuild the original 52 year old master brake cylinder. Just imagine how much wear can be put on a brake cylinder in 52+ years!

When my master cylinder blew the seals on my '50 F1 I replaced it with a brand new master cylinder. If you plan to use your truck on today's busy roads and quick moving/stopping traffic you might want to reconsider buying new. Especially if this unit is going into a heavier F3 truck.

 

I'm with Ron, I bought a new master cylinder for my 60 from Carquest store for about $50. My truck is only 43 years old but it gives more peace of mind to know the brakes are new. Since the I have converted to front discs so if anyone needs complete front brakes from a 60 F-100 I have it.