M275 trailer towing

[cphillips]

I recently purchased a 1967 M275. It runs great and just last weekend I sand blasted and painted it now it is going all back together. My question is that I plan on pulling a small civilian lowboy trailer behind it to haul my classic tractors on and I do not see any way to apply the trailer spring brakes when parked. I looked on here and saw some guys putting tractor protection valves or parking break valves, what ever you want to call it on their 5-tons, but nobody putting them on a deuce tractor. I do not really understand how the brake system actuates for the trailer since the truck is air over hydraulic but the trailer is full air, I assume there is a valve somewhere but I just not familiar with it. Have any of you M275 owners pulled a civilian trailer with full air brakes and if so what did you do about parking brakes?

 

[mhassett]

I have the same question.
MHassett
Bush, LA

 

[NDT]

I do not live in a hilly area so I just use the manual parking brake. I suppose the only way to apply the trailer spring brake is by disconnecting the emergency line. I retrofitted a tractor protection valve on my 275.

 

[cphillips]

NDT, I am mostly likely going to be putting a tractor protection valve on mine too, but obviously that is not the same thing as the dash controlled parking brake valve, I would like to have both a tractor protection valve and a parking brake valve for the trailer and set it up like any other semi where you pull the tractor protection the parking brakes apply. I think you would tap into the same lines as the trolley valve but I really am not to sure, I was hoping somebody had put a trailer parking brake in one of these things at some point. Or if I could plumb up the tractor protection to cut supply to both the service and emergency that would work too.

 

[Recovry4x4]

FWIW the M275A2 has a shuttle valve and a tractor protection valve from the factory.

 

[MWMULES]

I just do what the manual states,
Truck parked on level ground, engine off, handbrake
set, wheels chocked. Easy peezy

 

[cphillips]

The truck does have tractor protection, is it integrated into the trolley valve, I was not aware that it had one.

 

[NDT]

Exquize me? You can open the emergency gladhand valve and drain the air in seconds.

 

[cphillips]

NDT, if the truck does already have tractor protection built in like recovry4x4 says then absolutely ill just crack the gladhand open and drain it but if I was going to add tractor protection I just figured I'd add a valve in the cab too, and be set up like any other semi.

 

[Recovry4x4]

From the manual.

 

[cphillips]

Thanks Recovry4x4, I read most of the manuals but never saw that, it really makes me feel better towing a trailer with it knowing I never will loose total air pressure.

 

[NDT]

Recovery, I see the tractor protection valve in the 34P, but my A2 s/n 10277 never had one, it was plumbed like the slick and A1.

 

[NDT]

cphillips, does your truck have the valve? It should be under the catwalk.

 

[Recovry4x4]

Recovery, I see the tractor protection valve in the 34P, but my A2 s/n 10277 never had one, it was plumbed like the slick and A1.

Are you sure? They are well hidden on a crossmember under the 5th wheel. The valve under the porch is a shuttle valve. I don't recall ever checking my 52 M275.

 

[cphillips]

NDT, Ill check tomorrow or saturday, there is a valve like thing in between the air line and the gland hand under there by the fifth wheel. I have never encountered a situation where the valve would kick because I always tried to avoid them because I thought the tractor didn't have the valve in the first place. My truck was redone in 88 by the military so maybe it was added then, who knows. I'll try pulling the emergency gladhand while pressurized and see what happens, if it stops flowing I guess it does have one. Looking at the valve though I thought it was what controlled the service line but I never actually traced the lines coming from and going to it. I'll update this weekend.

 

[NDT]

Are you sure? They are well hidden on a crossmember under the 5th wheel. The valve under the porch is a shuttle valve. I don't recall ever checking my 52 M275.

Im sure. I sandblasted every inch of that frame personally. Maybe it was a mwo or running change.

 

[Recovry4x4]

OK. Guess you never know with the DOD.

 

[cphillips]

NDT, Recovry4x4, I checked this weekend and mine does not have the tractor protection, the box under the fifth wheel simply splits the air to go to the gladhands for the tractor trailer and the fifth wheel trailer at the rear.

 

[73m819]

NDT, Recovry4x4, I checked this weekend and mine does not have the tractor protection, the box under the fifth wheel simply splits the air to go to the gladhands for the tractor trailer and the fifth wheel trailer at the rear.

This was the way my old m52 was setup, NO protection valve