Re: [MV] Split braking system; some considerations.

From: ddoyle9570@aol.com
Date: Wed Nov 13 2002 - 06:19:18 PST


In a message dated 11/13/2002 9:01:13 AM Eastern Standard Time, super_deuce@hotmail.com writes:

> Question: Has anyone tested the hand brake at any speed other than for
> parking?

I suspect that somewhere around here I have an APG test report that addresses this. I'll see what I can dig up.
I do have in front of me at this moment the specifications for the 5 ton trucks. The parking brake is refered to as just that, a parking brake (not an emergency brake)...it says: "Application of the hand brake shall hold vehicle motionless on a dry concrete 40 percent grade, when deaded up or down grade with rated payload less towed load." The parking brake shoes are the same on both the G-742 and G-744 series trucks, so I suspect performance to be the same. It been a long time since I studied any of this type thing, but I suspect the forces required to hold 30000 stationary on a 40% slope are minor compared to those required to bring 20000 lbs at 50 MPH to rest.

How good is it at slowing the vehicle in case of service brake
> failure?

> Also, has anyone ever experienced total brake loss with the
> deuce?

Not with a deuce....I have lost power assist on a M62 five ton wrecker (makes a believer in power assist out of you), and I have had a total brake failure in an M123A1C ten ton tractor. I can tell you for a fact that at 30 miles per hour with no brakes in one of those, the parking brake lever is just something else to hold onto.

Regards,
David Doyle



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