1961 not holding brake pressure

[My61bird]

I’ve been going through the brakes on a 1961 Thunderbird I pulled out of the original is barn where it’s been since 1974, and so far I’ve changed two metal brake lines, every soft line, Which were clogged, and every wheel cylinder and bench bled the master I thought it was working, but after bleeding each wheel I’m having problems getting them to work as pressure is coming out when I pump them up along with air and I could feel the front hubs working when it’s up on Jack’s but the rear brakes aren’t locking up and the pedal isn’t coming back up on its own, and while taking a break with a stick holding down the pedal I noticed The front brakes were engaged when I took the break but when I came back they were spinning freely. So is this an indication that my master cylinder is not holding pressure or could I be doing something else wrong?. Thanks for any help.

 

[sre]

It does sound like the master cylinder is bleeding back. Did you take the master cylinder apart?? If it's the original then it is probablu leaking back. You may be able to buy a kit and rebuild it, however I would take it apart and inspect the cylinder bore to see if there may be pitting or corrison inside.

 

[74 Harley]

If you haven't changed the master cylinder then just do it. It's far too old to be safely serviceable. Booster as well. While you are in there did you remove and clean the proportioning valve? If not, well you know the drill...

 

[My61bird]

Yeah thanks, I think your all right about the master cylinder which as far as I know is the original that doesn't surprise me would be bad seeing how just about everything else so far became toast just sitting in the old man's Barn for close to 50 years I just started a new one.

 

[Ward 57]

Yeah thanks, I think your all right about the master cylinder which as far as I know is the original that doesn't surprise me would be bad seeing how just about everything else so far became toast just sitting in the old man's Barn for close to 50 years I just started a new one.

Good luck, it's an enjoyable journey. Lots of frustration but once you figure it out, a short celebration then off to the next project.

 

[My61bird]

So through the magic of Amazon prime I already got the new master cylinder I ordered last night I might take a break from working on as I’m exactly like my T-Bird today after yesterday, as in old and worn out, But just wondering what you think about this rubber boot that came with the new one? As I have a feeling after watching a few videos mine won’t have it and wondering should I leave it on if it doesn’t and do you think I’ll need to adjust the pushrod when putting it on? Thanks again for all your help.

 

[Ward 57]

The boot should most definitely be there. It's intended to catch any possible leakage. As a general rule the throw is adjusted under the dash at the pedal.