Bleeding brakes!!!

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David Boxall writes:

I have recently replaced the brake boosters on my '69 1750 Spider, and I
am having trouble expelling all of the air from the brake system...

^^^^^^^^^^^

David, were the boosters new or rebuilt? If 'rebuilt' you might want to
remove them (yeah, I know) and remove the small diaphragm (as opposed to
the large one). The rod from the diaphragm rides on a small aluminum
part called the plunger valve. It also has a rubber seal on it. This
valve is extremely prone to sticking if the car / brakes have not been
used for some time. It is also very easy to overlook when rebuilding,
unless one is aware of the problems.

You will never bleed the brakes if this valve is frozen.

If you have managed to find brand new boosters, skip that and ask
yourself how old are the seals in your master cylinder? If you are
positive they are in good condition there is one last (in all
probability) source of fluid not getting to where it should be and that
is in the brake bias valve near the back, but before the rear flex hose.

Remove and disassemble. Handle all with care, because it is extremely
doubtful you can find replacement seals. It might well be plugged up
with yuck. That is a technical term which means what happens when water
and brake fluid do when they try to unite and have sat around for some
time thinking about it.

Clean it out with denatured / isopropyl alcohol, put it back together.
Try bleeding once more (personally I'm a big believer in the significant
other pumping method) and I'll just bet...

Let us know which (if any) step solved it,

Biba
Irwindale CA

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