I have a '56 F-100, with the original master brake cylinder. It's leaking out the front, so it looks like I need to rebuild it. I have ordered a rebuild kit. Can anyone give me some tips or hints to make this an easier job? Also the truck has drum brakes. What is the best process for bleeding the air out of the master cylinder and brake lines when I get the master cylinder installed?

 

I havent rebuilt one but I do know they tend to get pitted in the bore so look for that and I think that your supposed to hone it lightly to clean any rust that might have formed over the years.
Once back together bench bleed the master put it in a vise at the flange plug the line holes with correct threaded plugs and fill the master about half way and slowly push the rod in and out not more than 1/4 inch dont want to over do it and you should see the bubbles coming out inside the master when the bubbles are gone the rod pressure should get fairly solid the install back in truck hook up the lines and have someone put light pressure and crack the lines to bleed out there first a couple of times then what I usually do is top the master off leave cap off and open one bleeder screw at a time and let it gravity bleed watching the level at the master this will push some of the air out at the wheels then top off master close lid and bleed with foot pressure starting at the right rear,left rear, right front then left front
make sure you dont run the master dry just check it often
I know this is a long read but I hope it helps
Jeff

 

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Have rebuild master cly's many times but not a 56. A hone if needed is sold at Advance auto. Be sure keep everything clean, it's easy to rebuild. If you're like me I like to have the experience at least once with hand's on in rebuilding everything. Have rebuild starters, alternator's, ect. But now like today I picked up a rebuild master cly for my 58 at OReilly Auto $27.00. I did looked around could not fine a rebuild kit for a 58. Good for you I know you will enjoy you truck more because you did it yourself! Let us know how it go's! Im rebuilding the brake's on my 58 panel truck. The wheel cly's $14.00 each, Brake hose $20.00 each at Advance Auto. I sure you know when the rubber brake hose get's old it swells and close's up. Hope this helps!

 

 

I agree with just replacing it. If it's leaking, that means there's pits in the bore. You'd have to remove a lot of metal by honing to eliminate a pit... imagine removing a pothole in your driveway by digging away all the rest of the drive down so it's level with the bottom of the pothole.

For a really long term restoration, consider getting the bore sleeved with stainless or brass. Local automotive machine shops may do that, but it'd be safer to go with a shop that advertises that service in Hemmings.

 

if it's like our 55 it's pretty easy to do. take it apart and see if it is pitted. our had a bad cup but no pits. it was $13.?? at auto zone. had it next day. o'reill'y didn't have a listing on it nor did advance. we don't have a napa so auto zone saved the day for me. it was easy to do. bench bleed was all we had to do on ours.

 

Haven't done one in a long time but it's not too tough of a job. Sometimes buying a rebuilt MC is about the same price as the kit...

 

Hi Jeff!

Thanks for the reply. I really appreciate you taking the time to write this up. I think what you wrote is really going to be helpful! I didn't think about the MC getting pitted inside. Maybe I should of just replaced it. But I've been spending a bunch of cash on this thing, and I'm trying to economize where I can! Thanks again!

 

Hi!

I just wanted to Thank You all for the replys,information and support. The great thing about this web site and threads is there is much information to be learned. All one has to do is ask!

 

^^^ your welcome glad to help
Jeff