BRAKE INSTALL TIPS
KEYS TO GOOD BRAKE LIFE Read your old shoes and drums. There is a story.
BEFORE DISASSEMBLY 1. Apply brakes per CVSA procedures @ 90 PSI to check slacks for: a. Applied angles. They should be equal on all wheels. b. Equal stroke length. c. If manual slacks, they should not violate the 90° rule. 2. Check wheel endplay. If too loose or tight, replace all bearings and races. 3. Check all air hoses for wear or cracking. 4. Check air chambers for wear or leakage, including center seals of springbrakes. PULL WHEELS, BUT BEFORE REMOVING SHOES … 5. Check shoes for: a. Uneven wear top to bottom per wheel b. Uneven wear across axle c. Uneven wear front to rear if a tandem d. Glazing e. Heat checking 6. Check drums for: a. Wear over .080 or uneven wear b. Glazing c. Heat checking d. Hard spots or evidence of overheating REMOVE OLD SHOES AND HARDWARE 7. Replace drums as needed. 8. Inspect spider for wear and squareness. 9. Check S-cam for wear at both bushing surfaces. 10. Replace all cam bushings. 11. Inspect brake chamber brackets for damage. 12. Check for wear at clevis pin area of slack adjusters. 13. Inspect bearings and cups. When replacing any bearing, always replace the cup. 14. Replace all oil seals. 15. Check axle vents if drive axle and/or replace all filler plugs in hubcaps. 16. Replace hubcap if leaking or face is cloudy.
RE-ASSEMBLE FOUNDATION BRAKE 16. Replace all shoes. Be careful to replace like for like design as many shoes look similar! 17. Replace all attaching hardware lubricating the applicable components. 18. Inspect/replace axle nuts and keepers as needed. 19. After wheel is reinstalled, adjust bearings per axle manufacturer specifications. 20. Adjust all slack adjusters. ROAD TEST WHEN READY, AND AFTER ROAD TEST … 21. Re-check air chambers for proper operation and equal stroke. 22. Re-check applied brake slack angle. Do not violate the 90° rule if manual slacks. 23. Re-check and re-adjust bearings if needed.
TECH TIPS When replacing drums, replace both across the axle, preferably all 4 if tandem.
ALERT: If you find irregularities in
steps 5 or 6, troubleshoot foundation brake and air system before removing shoes. Something is wrong! Also recheck friction selection.
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