Usage:
769C, 773B, 777 Trucks;
768C, 772B, 776 Tractors
Description of Change: The parking brake valve on the above machines has been improved to eliminate possible oil leakage. This leakage was caused by pressure spikes in the drain cavity. The new valve has internal relief passages to prevent pressure spikes and a drain line from the valve body to the hydraulic tank.
Adaptable To: The new 9T2174 and 9T2175 Brake Valve Groups are a direct replacement for the former 1U2646 and 1U2649 Brake Valve Groups respectively. The effective PINs for both the new and former brake valve groups are shown in Chart A.
768C Tractors And 769C Trucks
To convert an earlier 768C Tractor or 769C Truck with a 1U2649 Brake Valve Group to the new valve and drain line, refer to Chart B.
1. Install the valve, hose and clip as shown in Illustration 1.
Illustration 1. Installation of valve and drain line, 768C, 769C.
2. Connect the elbow, seal and connector as shown in Illustration 2.
Illustration 2. Connection of drain line to 9T2174 or 9T2175 Valve Group.
3. Install the connector and seal as shown in Illustration 3.
Illustration 3. Connection of 768C, 769C drain line to hydraulic tank.
4. Connect the hose assembly to the hydraulic tank at port (A) in Illustration 4.
Illustration 4. Location of drain port on hydraulic tank.
772B Tractors and 773B Trucks
To convert an earlier 772B Tractor or 773B Truck with a 1U2649 Brake Valve Group to the new valve and drain line, refer to Chart C.
1. Install the valve, hose, clips, bolts, washers, and nuts as shown in Illustration 5.
2. Connect the elbow, seal and connector as shown in Illustration 2.
3. Install the connector, seal and elbow as shown in Illustration 6.
Illustration 5. Installation of valve and drain line, 772B, 773B.
Illustration 6. Connection of 772B, 773B drain line to hydraulic tank.
4. Connect the hose assembly to the hydraulic tank at Port (A) in Illustration 3.
776 Tractors And 777 Trucks
To convert an earlier 776 Tractor or 777 Truck with a 1U2646 Brake Valve Group to the new valve and drain line, refer to Chart D.
1. Install the valve, hose, clips, bolts, washers, and nuts as shown in Illustration 7.
Illustration 7. Installation of valve and drain line, 776, 777.
2. Connect the elbow, seal and connector as shown in Illustration 2.
3. Install the connector, seal and elbow as shown in Illustration 8.
Illustration 8. Connection of 776, 777 drain line to hydraulic tank.
4. Connect the hose assembly to the hydraulic tank at Port (B) in Illustration 3.