Re: '56 Patrician Brakes

Posted by BH On 2012/10/18 9:21:51

JP -

OK, that jogs my memory of your firm pedal issue from another thread. I only asked because some people complain that the power brakes seem touchy.

There's no factory-provided adjustment that I know of - not even internal. I suppose there's a way the assist could be tweaked, but have never needed to do so. More likely, there's a problem somewhere.

To check the integrity of the reservoir, just remove and plug the hose and then test drive to see if that has any effect on pedal feel.

You really shouldn't have to add a vacuum pump to the power brake system. The V8 should develop more than enough vacuum to operate the power booster - UNLESS there's a pretty substantial vacuum leak somewhere. The vacuum reservoir (tank) is only there as a reserve. The vacuum pump on the OE oil pump is only there as an auxiliary source for the vacuum wipers.

Also, make sure the horsehair filter on the side of the booster shell isn't clogged. For the power piston to move in the direction of vacuum (and help apply the brakes), there has to be a way for air to enter the opposite side.

I should add that I once experienced a loss of power assist in one of my V8s, and when I removed the toe plate and end cover, with the BTV still in-car, I found that the hose that supplies vacuum to the power piston had slipped off the fitting that goes through the shell. Turns out some PO had foolishly replaced the large-diameter, thick-walled, formed vacuum hose with common fuel hose. Not only was the fuel hose a bit hard/stiff, but it didn't fit the booster fitting very well - even with mechanic's wire that had been twisted on each end (when the OE part never used any clamps). I slipped the hose back on (until I was able to scavenge a good used OE hose) and problem was solved.

WRT to dim instrument lights, are you sure you don't have a problem with the rheostat in the headlight switch? That's a common failure. Decades ago, as parts had become scarce in this area, rather than replace the entire switch on his 56 Exec, my dad removed the common (black?) feed wire for the instrument cluster lamps from the headlamp switch and plugged it into a separate rheostat control that he scavenged from an old electric heater. However, I can't recall where he picked up the feed for that rheostat - perhaps another terminal on the headlamp switch. Just as a test, you might temporarily unplug the dash light feed wire form the headlamp switch and wire it up to a hot circuit just to see the full brightness possible within the current limits of your electrical system.

Hope this helps.