Contents
What does the hand valve do?
Closing the hand valve releases the brakes by closing off application air. Air pressure in the chambers and lines will exhaust, also as explained in the previous foot-valve application.
Where is the trailer hand valve located?
steering column
The hand valve, as shown in Figure 2-7, is normally located on the steering column and its function is to apply the trailer brakes only, while the foot valve operates both the tractor and trailer brakes.
What is hand control valve?
The hand valve, or “spike” (Fig. 39) is added so that you can apply the trailer’s brakes independent of the tractor. The hand valve is typically supplied from primary and secondary circuits and plumbed to a double-check valve (which is also fed from the foot valve).
How do you connect glad hands?
When connecting the glad hands, start with the two seals together and the couplers at a 90-degree angle to each other. A quick, downward snap will join and lock the couplers. Vehicles equipped with dead-end couplers should have protection plates in use whenever the vehicle is used without a trailer.
What is the principle of control valve?
A control valve is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller. This enables the direct control of flow rate and the consequential control of process quantities such as pressure, temperature, and liquid level.
When inspecting the air compressor the driver must look for?
When inspecting the air tanks, the driver must check for insecure mounting. When inspecting the air compressor, the driver must check for a loose, frayed or cut drive belt, as well as insecure mounting bracket or fasteners.
What do glad hands connect to?
This term refers to the coupling device used to connect the service and supply lines of the trailer to the truck or tractor. These couplers have a snap-lock position and a rubber seal that prevents air from escaping.
What is the hand valve on a tractor?
The hand valve, or “spike” (Fig. 39) is added so that you can apply the trailer’s brakes independent of the tractor. The hand valve is typically supplied from primary and secondary circuits and plumbed to a double-check valve (which is also fed from the foot valve).
What is the hand control valve on a trailer?
Trailer hand-control valve. The hand valve, or “spike” (Fig. 39) is added so that you can apply the trailer’s brakes independent of the tractor. The hand valve is typically supplied from primary and secondary circuits and plumbed to a double-check valve (which is also fed from the foot valve).
When to use the hand valve or the foot brake?
The foot brake sends air to all the brakes on the vehicle (including the trailer (s). There is much less danger of causing a skid or jackknife when using just the foot brake. Never use the hand valve for parking because all the air might leak out, unlocking the brakes (in trailers that do not have spring brakes.)
When to use trailer hand valve or air brakes?
The trailer hand valve should be used only to test the trailer brakes. Do not use it in driving because of the danger of making the trailer skid. The foot brake sends air to all the brakes on the vehicle (including the trailer(s). There is much less danger of causing a skid or jackknife when using just the foot brake.