Military-Vehicles: [MV] Dual master cylinder conversion for M37 ???

[MV] Dual master cylinder conversion for M37 ???

Alan Bowes (alan_bowes@phast.com)
Wed, 23 Jul 1997 11:09:41 -0600

Hello, y'all:

I'm interested in getting your opinions regarding a possible conversion =
to a dual master cylinder for an M37. It appears (though I haven't =
confirmed this) that a late-model WM300 dual master cylinder might =
install fairly easily in an M37.

Obviously, front-to-rear proportioning could be an issue. Does anyone =
know how proportioning is handled on the dual-master-cylinder WM300? =
(Integral? Separate valve? No proportioning?) How about proportioning =
ratio?

Is it a bolt-up installation? If not, what alterations are required? I =
haven't had a chance to actually inspect a WM300 dual master cylinder, =
so all I have to go by is a not-too-detailed photo that I saw somewhere.

If installed correctly, I think that a dual master cylinder could be a =
valuable safety modification...one that I'm willing to make in an =
otherwise original daily driver. I'm also looking into seat =
belts/harnesses for the same vehicle. Any suggestions?

By the way, I've received widely varying opinions from several =
knowledgeable people on this topic. Apparently, some folks think the old =
single master cylinder is perfectly safe, while others favor the =
redundancy of the dual cylinder. As to personal experience, over the =
years I've experienced two brake failures that fortunately took place in =
non-critical situations. One was due to metal fatigue in a steel brake =
line going to the front wheel cylinder of an MB (perhaps the retaining =
clip had been left off at some time in the past, though it had one when =
I got it). The other involved spot welds breaking on a brake shoe (very =
unusual). In both cases, it would have been helpful to have a dual =
master cylinder.

I've heard about failures in dual master cylinders, too. However, one =
common scenario is when there is a problem in the rear circuit that goes =
unnoticed since most of the braking power is handled by the front =
wheels. Then when something goes wrong with the front circuit, you have =
no brakes at all.

Having owned and flown several small aircraft over the past dozen years, =
I guess I'm a little more tuned in to the idea of redundant systems than =
some folks. I suppose one becomes accustomed to having some kind of =
backup.

Opinions?

Alan

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