If you do decide to just replace a diaphragm NEVER NEVER remove the clamp on a chamber with 2 sets of them.
NEVER .
Putting it another way if the chamber has only 1 air line going to it you are safe, If it has 2 air lines going to the chamber LEAVE IT TO SOMEONE WHO IS SURE WHAT THEY ARE DOING. If you pull the wrong clamps on a chamber with 2 sets of clamps it could kill you.
Here is all it takes to relieve the tension from the spring on that SERVICE BRAKE diaphragm so you can switch it.
I have finished up with the steer axle and I neglected showing some important steps that I can demonstrate with the tag.
Simultaneously take a large screwdriver shove it in the cleaves of the slack adjuster and pull back with one hand (just like you were checking slack) and with your other hand clamp the push rod with some vice grips right at the housing so it can't spring back
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Now when the 2 clamps are removed the tension is gone.
The 2 diaphragms on the steer were dated 1981 so that means they were not only original but sat on a shelf for 4 years before they were used. The new ones I'm installing were manufactured in 07. No good Mr. Parts guy, no good. I expect my parts deli fresh, thank you.
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