Re: New Member - Help with disassembly of Power Brake Unit

Posted by BH On 2007/4/9 19:11:56

Boro-

From what I can see of the spring in your pic, I gotta say it looks fairly robust. The springs I've removed from other (unrebuilt) units were much more delicate. I wonder if your spring has already been replaced with some repro as part of a past work by a qualified rebuilder.

The minor kit should include a new poppet for that valve and you should use it. Just hold the existing valve poppet against the seat and depress the spring from the C-washer retainer, and you can slide that retainer out of the groove, near the end of the stem. Then, remove the spring and inspect it for any weak points caused by corrosion (or nicks). During reassembly, be sure to take the extra step or two in the Packard shop manual to install the valve properly and verify that it works. Otherwise, you'll likely end up removing the unit from the car again. (I'm not sure how accessible the valve is with the unit installed. I've removed the reservoir cover with the unit on-car, but the steering column is an obstruction to doing much else.)

Your C-washer retainer doesn't look too bad to me. I suspect any protective plating has merely failed. If you're upgrading to DOT5 (which requires replacing EVERY rubber part in the hydraulic system and flushing the steel lines to remove all traces of DOT3), there will be no problem. If you're sticking with DOT3, then - every few years - you'll wanna siphon the contents of the reservoir and push a fresh pint of brake fluid through the system, via a full bleed, to remove moisture-contaminated fluid from the system - as the reservoir is NOT completely sealed to atmosphere.

Be very thorough about your brake work on any old car - no matter what system it has.