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Tag Axle parking brake chamber replacement
I just finished changing out all of my norgren valves and ride height valves under my bus and found that a tag axle parking brake chamber is leaking air. I have never replaced one before. I’m debating changing it myself; it looks simple enough. Can someone offer advice or the steps needed to do this correctly. Thanks.
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7 Replies
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I did all mine also, Like Don said Piggyback not hard, cage brake chamber
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They are relatively simple to change. Two nuts hold them in place. You likely will have to cut the threaded push rod.
Get your parts at a truck parts store, likely having to make one from parts from a “piggy back” and a service brake chamber unless you don’t mind the couple of hundred dollar penalty buying them from Prevost.
But never ever get complacent about the energy stored in a compressed parking brake spring. Make sure when you cage the brake the “T” bolt is correctly seated.
If in doubt ask a friend or someone with some experience to give you a hand. I suspect you are going to replace all brake chambers if this is the first time any of them has leaked.
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I just finished replacing the brake chambers on the tag axle. All went well until the final step on one side. I turned the adjusting nut on the slack adjuster until it stopped and was then going to turn it back 1/2 turn, but I could not get the adjusting nut to reverse direction at all. Therefore, this one side is stuck with the brakes on. What should I do?
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Pull the pin and see if you can get the slack adjuster to release.
The tag slack adjusters pick up a lot of road dirt. I had one lock up on a trip. I replaced all 8 but only about 6 months later. If needed you can drive with the pin pulled on one side. I don’t think you notice a difference the tags don’t have much weight on them.
We don’t ever talk about changing them as a PM item but we have several reports of the early to mid 90’s units locking up.
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Thanks, simply loosened the bolts on the chamber, took out the pins, cleaned it up and I was able to get it to move. All is well.
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Automatic slack adjusters are like a ratchet, they move freely in one direction(tighten) only. To loosen them the desired 3/4 turn, there is a “pawl” needs to be released, pulled out.
This caution is on p.53 of this 68 page Meritor mx manual: Meritor mm4m manual
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