Trailer Brake Valve

[Rob]

In the cab of my R model, there are two trailer brake valves. One is in the normal area on the steering column, and the other is a bit lower. The handle of the second one blocks clear access to the starter key switch. I think the truck was a dirt, or lowboy hauler, but have no idea what the second control was used for.

Any ideas?

Thanks,

Rob

[HK Trucking]

In the cab of my R model, there are two trailer brake valves. One is in the normal area on the steering column, and the other is a bit lower. The handle of the second one blocks clear access to the starter key switch. I think the truck was a dirt, or lowboy hauler, but have no idea what the second control was used for.

Any ideas?

Thanks,

Rob

Rob, that tractor was more than likely used to pull a removable gooseneck lowbed equipment trailer.

one trailer valve (trolley) is probly for the trailer brakes, and the other one is probly for the drive axle brakes on the tractor, this way when the trailer is detached, the tractor brakes could be applied.

Does that tractor have spring (maxi) brakes?

We had a DM at the place I worked back east that didn't have spring actuated parking brakes & we had a setup like what you're describing to hold the tractor brakes while it was detached.

[Rob]

Rob, that tractor was more than likely used to pull a removable gooseneck lowbed equipment trailer.

one trailer valve (trolley) is probly for the trailer brakes, and the other one is probly for the drive axle brakes on the tractor, this way when the trailer is detached, the tractor brakes could be applied.

Does that tractor have spring (maxi) brakes?

We had a DM at the place I worked back east that didn't have spring actuated parking brakes & we had a setup like what you're describing to hold the tractor brakes while it was detached.

Hi Herb, that would make sense as the truck does faintly have a construction company's name on the doors. There is also a air shift pto handle in the dash but the lines are capped under the truck and the pto/pump is gone. There is however, a handle sticking up through the floor that is not connected to anything. The truck does have spring brakes on the front drive axle, and the rear chambers are not spring type. I plan to convert these to spring brakes as I'm going to use the truck as a winch tractor. I do not see evidence of any "risers" ever being installed, and there is no damage in the rear to the frame area. There is a deckplate behind the cab that has a 4 inch hole like a hydraulic tank fill neck would protrude up through, or maybe a hydraulic coupler for a dump trailer. I had never seen two trolley valves and I had wondered if it had something to do with the tractor brakes but they do not apply when the handle is pulled. It also could be disconnected.

Thanks,

Rob

[Guest Bollweevil]

Second valve operates the Caterpillar brake saver

[Rob]

Second valve operates the Caterpillar brake saver

Just like a light bulb comming on, I think you're right!! The gauge on the dash that says "Brakesaver Pressure" does have an airline running to it. Duh!!! I never thought anything about that. After work today I will have to see if it in fact works by driving down the road and applying this thing.

Do you have any experience with them?

Rob

[Guest Bollweevil]

1693 Caterpillars were rated at the rear wheels, It was not uncommon for a well prepared 1693 to put 550 to 600 hp to the ground. The major drawback was the 3.5 to 4 mpg, that went with such a set up. Not as much of a problem at 25 cents gallon, as now.