Park brake not holding

Got a 2002 c7500 with air brakes, the parking brakes are not holding... are they just to loose? Thanks for any recommendations

Probably. Try adjusting them.

If they are air brakes with maxi cans and the park brake does not hold, it won't stop very well either. It may need adjustment, of it may be that the pads are worn past the limits and there is no more adjustment left.
Check the stroke on the air can. With the wheels blocked and brakes released, mark the rod, then apply the brakes and measure the stroke. 2" is the normal limit, and properly working brakes around 1" to 1.5" travel. If you have more, adjust them up tight and check again, but not before making sure there is enough material left on the shoes.

To adjust, with brakes released, tighten the adjustment bolt until tight, then loosen 1/2 turn. Measure the stroke again to be sure.

I'm not sure what brakes it has other than air, and it's an auto so I have to have a functioning parking brake...

You really need to educate yourself on the brakes if you're going to be driving this truck. It is YOUR responsibility to have your brakes in working order.

Shimmy1 said:

You really need to educate yourself on the brakes if you're going to be driving this truck. It is YOUR responsibility to have your brakes in working order.

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^^^^^^
What he said! If you need better advice take some pictures of the brakes and post them so people can make more informed suggestions.

Thanks guys... I understand the importance, I'm trying to figure it out. It won't roll on a hill but in gear it will move if that's a better description I just don't want it to be able to move. I've got pics but can't upload them...

Each wheel will have a slack adjuster. You need to chock the wheels, release the brakes, and set them up. Depending on how old the truck is, the slacks will either be manual or automatic. Most automatic ones have two pins (big one and small one) to connect the pushrod to the slack adjuster. There will be a little bolthead sticking out the end opposite the pins. Takes a 5/16" wrench. On the side, there will be a disk that's about ¾" in diameter. That's the lock. You pry it out with a small screwdriver to release the adjusting bolt. The best way to adjust the brakes is to jack up each wheel and turn the bolt until it's tight. Then, pry the lock back, and back off the bolt until you can turn the wheel. A tiny bit of drag is ok. Good luck.

It could possibly have wedge brakes (air operated) as well; I believe that with the advice given here and some google searches you should be able to determine what kind of brakes you have, and then go from there.

I assume they are air given the size of the truck, but if they are hydraulic it may just be a matter of adjusting the end of the actual parking brake lever to tighten the cable leading to the parking brake, which may be a drive line brake.

Before I make this any more confusing, try to identify for sure what type you have and then the folks here can steer you correctly on the adjustment procedure.

Given that it is a 2002 though you should have conventional air brakes. If so, I thought that auto adjusters were mandated by then, but I may be mistaken on that.

I could also be that the springs in the maxi cans are broken.

Old Doug said:

I could also be that the springs in the maxi cans are broken.

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That was one of my ideas too, even if only one or two are broke it might move easy.

Air chamber with 2 air lines going in the chamber is held by 2 studs the threaded rod is going to a lever that operates the drums. It is conected to 2 pins. Their is a 14mm bolt in the slack aduster? And a 10mm on the top? Trying to load pics. The brakes stop like a dream. Drums have 3/4 an inch of material left