Shop changed my brake chamber the other day so I was under the truck and noticed when it’s released it’s the same length as the rest but when applied its 5-1/2 inches long versus all the others at about 3-1/2. What’s going on here. I get it seems long but if I cut it down it looks like it’ll will push to far in when released. Brakes are type 3030 reg stroke round port. Chamber is the correct one.
Brake chamber stroke to long help
Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Mr79W900A, Jun 16, 2021.
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When released, it goes "all the way". But when applied, it will move until the shoes contact the drum. Seems like you need to cut two inches off, install it, and then readjust your shoes on that corner.
But you seem to know what you're talking about, so is that even possibly the problem? Did you already rule that out? When they're released, do the brakes on that corner have a larger gap than the rest? Have you already adjusted them?
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A few guys on here that know air brakes better than they know how to walk, but I swear I can't keep everyone straight.RocketScott and Rideandrepair Thank this. -
When applying the brake the rod comes our way to far. Whole chamber is new so I’m thinking maybe the slack adjuster is pooched.
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Shawn2130 and Rideandrepair Thank this.
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Th
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Still will require an initial adjustment even if its an auto slack adjuster. I'd start with with adjusting it manually and see how it looks.
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Shawn2130 and God prefers Diesels Thank this.
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The new chambers come with a tag, that explains stroke. Total stroke is something like 3-3.5”, maybe? II forget excactly. So ideally the rods out 1/2”-34” maybe when parking brakes released. Then when adjusted within 1.1/2 stroke, you still have some rod left, should it get out of adjustment. So if total stroke is 3.5” say, you can have a 3” stroke, and brakes will still grab barely. Bottom line, if the rods a little bit too short,or too long, they still work fine if within the 2” max stroke. That’s from rough memory on my part. The tag, explains it all. As long as they all look the same, released. They’re probably just fine. New rod should be the same length as the others. The long stroke your seeing when applied is taken up by the slack adjuster. First manually, then automatically each time you hit the brakes, one 1 or 2 clicks at a time. On my Trailer, I had 4 different rod lengths , from having them replaced so many times. I had no idea which was the correct exact length. Since I was replacing all of them, I started from scratch measuring, following the directions. In your case, the length is probably fine, if it matches the others.
Shawn2130 and God prefers Diesels Thank this. -
I hope I didn’t just totally confuse you. Lol. I honestly never knew exactly how the length was determined. Till I did mine last summer. The tag basically explains how to measure and cut the length. Too long, they’ll apply past a 90 degree angle. Too short, might not make contact, if it gets out of adjustment, and shoes/ drums are thin. So when applied the rod and slack should be just under 90degrees. Like 80-85 degrees. Basically at an L shape angle, any more risks braking power loss. That’s how I read it anyway.
John E. and God prefers Diesels Thank this.
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