Hello, I'm in the process of rebuilding my 57 treadle vac master and hit a stopping point - the vacuum piston. I have the manual and the instruction sheet from the Kanter rebuild kit. Just to give you an idea of where I'm at in the process: resivoir cover is off and drained, back plate off, air breather off, vacuum port off, hose off, felt washer off. I pushed the vacuum piston in a few inches and cleaned the bore with a wire brush to prevent rust from damaging the piston seals. The 57 manual says to remove all of the above and just "pull out" the vacuum piston. It feels like there is a hard stop on the piston and it won't release. Anyone know what I'm missing here?


Thanks!

 

Sorry, I don't but bringing the post back to the top. Hopefully someone who knows will see your post and reply.

John

 

A member(Karlskorner) had a post in 2012 called '57 Olds master cylinder rebuild (complete with Pictures). Excellent article.Shows step by step for rebuilding. Larry

 

Yes that is an excellent post. I read it before I started work. It covers the master but not the disassembly of the vacuum booster. Update, I removed the comp valve and can see no plunger on the hydraulic piston end - just metal. There also weren't any pieces in the check valve. Just the body of the valve with a brake line attached. This gets weirder by the hour. Still feel a hard stop on the vacuum booster and see no obvious way to release and remove it.

 

I sent a PM to Karlskorner to ask if he remembered any details about removing the vacuum piston. I will certainly post info here for future reference of others.

 

My Booster is currently off the car.I looked at it and the only thing that seemed to be holding it once you have the hose connection ( the metal part removed) seemed to be the small screw that holds the filter cover on.Mine is A '55 but it should be the same. When you once get it apart,Several have recommended using neatsfoot oil to lubricate the leather seal. You might try turning to left or right while pulling,it should pull out. Larry

 

Ok, not sure why I didn't think of this sooner, but I put compressed air to the vacuum tube and pulled a few times. It came loose! Looks like quite a bit of white powdery corrosion on the onboard face of the vacuum piston causing a lock up with the actuator for the hydraulic piston. Lesson learned and hopefully can help others. A bit of an algebraic engineering solution.

 

The Neatsfoot oil softened the leather seal,but do not soak the packing underneath we made this mistake and it swelled up to where the piston would not move in the cylinder. We then cleaned the packing and it works ! Larry