When Should S-cam bushings be replaced?
If the radial play is 0.030 of an inch or more, the cam bushing or camshaft is worn and needs to be replaced.
How can you tell if S-cam bushings are bad?
The warning sign on s-cam wear is the shoes starting to stick out of the drums on the inside and wearing unevenly (more wear on the bottom than the top shoe). The worn parts put more pressure on the inside (axle side, not wheel side) surfaces, wearing the drum into a bell shape.
What is an S-cam bushing?
An S-cam is part of a braking system used in heavy vehicles such as trucks and wheeled machinery. It consists of a shaft, usually around 4 to 25 inches long, turned at one end by means of an air-powered brake booster and lever with an ‘S’ shaped cam at the wheel end.
How long do you grease an S-cam?
All S-cam tubes should be lubricated at 25,000 mile, re- gardless of brake brand. Fully lubricated brake S-cam tubes ensure that moisture and contaminants do not enter the cam tube, potentially causing corrosion, slow return, and seal damage.
How should you check that your service brakes are working properly?
How should you check that your service brakes are working properly? Wait for normal air pressure, release the parking brake, move the truck forward slowly, and apply the brake pedal firmly. You just studied 70 terms!
What does it mean when your brakes cam over?
Excessive brake drum depth and very thin lining of the brakes will cause the brakes to cam over. Cammed over brakes will cause the brakes to lock up and you won’t be able to move the trailer. When the s-cam cams over, it rotates past the rollers on the brake and wedges the brakes against the drum.
How much does a brake job cost on a semi truck?
Expect a brake job of replacing brake pads and rotors to cost $250-$400 per axle on average.
Which of the following is the best practice when instructed to block the wheels on a tractor trailer combination?
Which of the following is the best practice when instructed to block the wheels on a tractor/trailer combination? Place a pair of wedged wheel chocks on one tractor drive axle and one trailer axle wheel.
When spring brakes are on you should never?
Never apply the brake pedal if your spring breaks are activated. Brakes can be damaged if they are subject to both springs and air pressure.
How does vehicle weight affect stopping?
The effect of vehicle weight on stopping distance. The heavier the vehicle, the more work the brakes must do to stop it and the more heat they absorb. But the brakes, tires, springs, and shock absorbers on heavy vehicles are designed to work best when the vehicle is fully loaded. Wet roads can double stopping distance.
What should I do with my S cam bushings?
Worse case scenario- get an 1.500 flap disc at lowes or somewhere, chuck it in drill press, get a cup of water handy (to dip it in and cool it off) and take them out til they have enough clearance like .002 . THen hit them a lick with a brake cyl hone or whatever is handy to sorta true them up laterally.
When to replace Cam bushing on Foundation brakes?
If the radial play is 0.030 of an inch or more, the cam bushing or camshaft is worn and needs to be replaced. Keep in mind that even if the radial play is below maximum, the next brake servicing may be several hundred thousand miles down the road, and too much radial play leads to uneven brake shoe wear,…
When to replace the grease seal on the S-cam?
Seals inside the cam tube are engineered to let excess grease out of the area, meaning new grease should be added until any dirty grease or condensation is visibly purged out of the end cam tube near the slack adjuster. Grease purging at the opposite end of the cam tube, near the S-cam head, indicates a bad grease seal that must be replaced.
How are the S-cams attached to the drum?
S-Cams The S-cams rotate from the torque applied by the slack adjusters, resulting in spreading the brake shoes which applies the braking force to the drum. The S-cams are supported by two nylon, grease lubricated bushings. Due to the high forces exerted on the cam bushings, periodic inspection, lubrication and maintenance is