One man brake bleeding

[Frank Murch]

20 years ago I had a brake problem, got a life time master booster and cylinder from PepBoys and all was good.  My wheel cylinders are all rebuilt with stainless steel sleeves and the springs, shoes and drums are all "new" (unworn, but over 10 years old).  The pep boys master started to fail and I got it on exchange. It is from a 1968. So I had a 63 master and booster rebuilt and swapped them in today.  Now I have nothing on the peddle and I am getting nothing out of the wheel cylinders with 20,40, 60 brake peddle strokes. 

Any ideas what is wrong??  Massive amount of air?  Any way to force brake fluid from the wheel cylinders??

I got nothin'

[24ro8f5mbs2jc]

My first thought is that the push rod is set incorrectly. It has to have the correct distance otherwise it will not move the floating piston to the correct position and open or close ports.

Check page 6-15 (1964 manual) on how to adjust the push rod.

When I did it on my car I took an old hotel key card and cut to specifications.

[24ro8f5mbs2jc]

No idea why the pictures upside down. Maybe it is to help Kevin see them?

Anyways the first measurement is in inch and the other in millimeter. Choose what you need.

[2o93f8rdftyzj]

Pictures are ok down here.:-)

[Frank Murch]

Because it was professionally rebuilt I would hope the setting is correct (maybe a bad assumption) I have an electric vacuum pump and I think I will start by a hard suck through the right rear wheel cylinder and see what happens.  If this is not enough, I am thinking to prime the master manually and if that does not work - pull it off and start looking inside

[1bt7pektvt387]

Frank,

Did you bench bleed the new master cylinder? I've always done this on American MCs because without it they sometimes will pump only air and no fluid.

You need a couple short lengths of spare brake line. Attach them to the outlets and bend the end of each into the fluid in the reservoirs. With the MC clamped in a vice, push and release the piston until only fluid and no air bubbles are going into the reservoirs. I use a wooden dowell to avoid damage to the bore. This will prime it and hopefully solve your issue.

[1bt7pektvt387]

Come to think of it, since the MC is already mounted you can perform the procedure I described with it still there. Disconnect the lines, fit the bleeder lines and use the brake pedal to bleed.

[Frank Murch]

Thank you - I think this is a great idea and likely the source of my issues!!

[Frank Murch]

No, I did not even think about it. But I think what you are saying makes perfect sense

[Kurt]

Yes. Definitely. If you did not bench bleed the master cylinder before installing it, that's a problem. I remember that was step #1 when I replaced mine a few years back. It took several minutes to bleed all the air out of the MC.