This was supposed to be an easy weekend project.
In the fall of 2005, my friend Carl and I filled the master cylinder of the 58
Plymouth with Castrol LMA (low moisture activity) brake fluid and bled the
brakes for the first time. When Carl tried the pedal, it sunk to the floor.
Thus began a frustrating ordeal that would last almost two months and take us
thru many bottles of LMA.
The first discovery was that several of the lines were leaking, including the
main line from the master to the brass four-way connector mounted
Above: Carl
is poised to step down on the brake pedal when I give the signal. This brake
bleeding scenario was repeated a number of times over the course of nearly two
months as we tried to resolve the brake problems.
Left: One of the issues encountered was a missing check valve in the
master cylinder, which is seen in this illustration from a parts book.
on the frame. After tightening, though, there was still no pedal.
Then a brand new wheel cylinder was discovered to be leaking and was replaced.
Another round of bleeding but still no pedal.
The next step was to remove the NOS master cylinder that I bought on eBay.
After disassembling it, an interesting discovery was made. The check valve was
missing. Could this be the problem ? Replacement and reinstallation still
proved fruitless. This was getting interesting…
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Thanks to unusually warm weather, we had some extra play time in my
unheated garage. More leaking brake lines in the rear led me to believe that
the stainless steel lines were not sealing properly against the wheel
cylinders, at least in the back. So conventional steel lines were made up.
Another trip to the auto parts store and another round of bleeding. This time
after several consecutive pumps, we started to get some resistance in the
pedal. But after releasing and waiting a few seconds, the pedal would sink to
the floor.
As the end of October closed in, there was no resolution in sight. We even
tried adjusting the free play on the power brake pedal, with no change. The
folks at the auto parts store were recognizing me by now from all the bottles
of brake fluid that I had purchased.
Along with earlier sunsets, November brought the beginning of the cold weather
season. It was time to get to the bottom of this. I fabricated plugs to shut
off one or more of the brakes in an attempt to narrow down the problem. First,
I shut off the rear brakes, leaving only the fronts operative. When I pumped
the brakes, there was, for the first time, solid pedal, which remained instead
of immediately fading.
This pointed to the rear brakes as the area where the problem resided.
Remembering how easily the rear drums came off, I decided that the shoes needed
adjusting. I snugged them up to the drums, then backed off a bit. I had a good
feeling about this, thinking that we may have found the final piece of the
puzzle. Sure enough, when I reconnected the rear lines, there was a solid
pedal. Tried several minutes later and the pedal was still holding. Problem
solved ! And without a moment to spare, as the next day the temperature dropped
significantly, ending the car working season until the spring.
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