Air over hydraulic brake information for possible M35a2 swap?

From: Bob Ternes (racecadet@yahoo.com)
Date: Tue Oct 05 2004 - 15:22:48 PDT


Hi Folks,

Me again - the troublemaker.

Well, it's been a hard lot to fill my need for a
.69 transmission (in the spirit of Formula 1 Tom,
I am fasterizing my M35a2 with a Cat 3208 but
need the high OD tranny), so I've started some
other projects in the meantime. I've sworn off
women for the time as trumping even my Jeep for
unpleasant surprises and so when I'm off work, I
own my time wholly. ;) I have been working on my
rockcrawler project and I should have a rolling
chassis (built from tube and M35 axles) by
Wednesday, and I've started to twist my head like
a slippery noodle around a new forking problem:
brakes on the deuce.

I was in a junkyard a few days ago and I saw a
beautiful Cab over engine Hino with some
functioning air over hydro brakes, and amazingly,
air still in the system. I pumped the brakes a
few times, checked everything out, and it looked
"good". I am dearly excited to put 1990's era
brakes on the deuce, if only to lessen the risk
posed by one hydraulic circuit brakes. The only
problem is that it was a single rear axled truck.
Will this pose a huge issue? Do I need to find a
system from a twin screw rear truck?

Does anyone know the ins and outs of air assisted
hyraulic brakes - like:
· Do I need a special proportioning valve, or
just hook em up and go? That would be my
druthers, and then work things out, say, if my
rear end developed a nasty lockup habit.
· Are there different PSI ratings for different
braking systems, or are they all programmed to
run at 60+ psi??
· I shouldn't need the double tank system that
this COE truck has, do I? I was just going to run
a single air line (like stock) to the new brake
valve and then branch off there?

Bottom line is that there's no snow on the ground
yet, and if I go grab that system myself it will
be cheap as. If it works, I'll grab it now, and
put it on as time permits, splitting up the stock
brakes into F and R circuits. I bet that I could
swap things out in a weekend, which means that I
could probably have this done by November if I
start now. ;)

Thoughts?

Thanks,
Bob Ternes
Boulder CO
1968 M35A2, undriven for a near record 10 days



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