Leaky Disc Piston! Help!

[Johnm]

Hey everyone!

So I finally finished rebuilding/replacing all of the brakes on my 69 F250 longbed 2wd. It has the stock front discs and drums in the rear. Before I did the rebuild everything was pretty much crap, but no fluid was leaking.

My problem is with the front driver caliper. After honing it out, I cleaned everything and replaced the seals on the pistons. For some reason it now leaks from the piston. I disassembled the caliper, cleaned and inspected, then reassembled. Leaking again, less this time though. The inside surface of the caliper was in fair/good condition so it seems to me like it should work.

Am I missing something?
*notes*
-I haven't had a chance to do a full bleed yet since I don't want to waste the fluid if it's just going to leak out.
-passenger side was in worst condition before rebuild and is fine.
-I haven't driven the truck in a year. Suspension bushings were replaced so suspension needs to settle still.
-booster and master cylinder were not replaced.

Help please! I wanna go drive

[Ranchero50]

If you over hone it, it will leak. Try some grease on the seal. Probably not going to make much difference but might help if it's rolling in the groove.

[Johnm]

I'll try that today. I didn't do too much honing or at least I don't think I did haha. Who knows what the guy before me did though! I'll grease it and try again!

[Johnm]

Well, you were right! The bore is too large. Now to find a replacement. Any suggestions from anyone on a source?

[Busboy]

Auto Zone has them as does O'Reillys. Napa does also but they are more expensive.