Lull 6K Service Manual - Manual (Page 581)

Brakes
Service Manual — Models 644B, 6K, 844C, 8K, 1044C, 10K 9-7
1. With the engine off, connect a 0–600 psi gauge to the test port marked
“BRAKES” located behind the cab step. Pump the brakes until the
gauge reads 0 psi.
2. Remove the brake pedal assembly (Item 1) by loosening the four (4)
1/4” nuts (Item 2) on the two (2) U-clamps (Item 3) and pushing the
pedal mounting pin (Item 7) out.
3. Remove the rubber boot (Item 9), being careful not to damage it.
4. Use a spanner wrench to remove the piston guide (Item 10) from the
body (Item 19).
5. Remove the flange head capscrew (Item 8) from the piston (Item 13).
Record the number of turns the capscrew was backed out.
Note: The flange head capscrew has thread sealant applied to the threads. Grasp
the piston around the large diameter end so as to not damage the sealing
area on the piston.
6. Remove the thread sealant from the flange head capscrew and piston.
7. Reassemble the flange head capscrew into the piston, turning it in the
same number of turns that was used to turn it out.
Note: Do not apply thread sealant at this point.
8. Install and use a spanner wrench to secure the piston guide to the
piston.
Note: Do not install the rubber boot at this time.
9. Install the brake pedal assembly (Item 1) onto the actuator base
(Item 6) by pushing the pedal mounting pin (Item 7) through the
U-clamps (Item 3) until centered in the actuator base.
10. Tighten the 1/4” nuts (Item 2) on the U-clamps (Item 3). Adjust the
deadband setscrew (Item 4) out so that it does not contact the flange
head capscrew.
11. Connect a 0–600 psi gauge to the brake test port located behind the
cab step. Start the engine and record the maximum brake output
pressure with the brake pedal fully depressed. If the pressure is
outside the range of 330–375 psi, adjust the flange head capscrew.
Note: Turn the flange head capscrew into the piston to decrease pressure and out
to increase pressure.
12. Repeat Steps 1–4.
13. Remove the flange head capscrew (Item 8) and record the number of
turns the capscrew was backed out.
14. Apply blue thread sealant to the threads of the capscrew, being careful
not to get thread sealant anywhere on the piston sealing area. Install
the capscrew in the piston and turn it in the recorded amount.
15. Install and use a spanner wrench to secure the piston guide to the
piston.