Mixed Stroke Length Brake Chambers on Same Axle

I have read that you shouldn't do it. During the process of troubleshooting some other things I noticed that my rear axle on the truck has two different 3030 chambers. I can clearly see the markings on them. One is a 3 in long stroke with the square boss inlets The other is a 2.5 stroke and has round boss inlets for the brake hose fittings.

I am thinking with two different sizes the slack adjusters were used to compensate for the difference. Maybe they are close enough to work but not technically correct? Any thoughts?

I know the MFG specifies a 3in long stroke. I was thinking of changing out the 2.5 with a 3 and readjust the slack adjusters. Do you think that is unnecessary? Thanks for your input and advice.

 

That's a good point I forgot about. Shame on the last mechanic. Shoddy work.

I'll change it out and readjust the slack adjusters. Thanks!

 

I found the regulation that covers this. (In case anyone else wants to know)

49 CFR Part 393 Subpart C

"Brake chambers. The service brake chambers and spring brake chambers on each end of an axle must be the same size."

One could make an argument that as long as they are both 3030 what is the difference, but who ever won an argument with the DOT? It's just easier to replace and move on with life. There's enough other DOT regs to put up with.