Brake chamber question

Whats the difference square port vs round. Gc3030 standard stroke. Had #2 axle chambers replaced over 4 years ago and I ended up with 1 of each. Replacing the pair again and looks like both will be round. TIA

 

Round is normal. Square is long stroke.

https://www.cvsa.org/wp-content/upl...tin-2014-02-ID-Long-Stroke-Brake-Chambers.pdf

Both chambers on the same axle should be of the same type.

 

Wrench told me the long stroke are the parking brakes.

True????

 

False I'd say. Square port just means they stroke 3" on a type 3030 vs 2.5" on a standard 3030.

I hope I'm listing the correct stroke lengths. Its been a few years lmfao.

 

If you use a long stroke on a regular brake setup you may wind up camming over the S cams. Then you have no brakes. You cannot substitute Willy nilly .

 

Round should be short stroke, square should be long. The tag is probably long gone, but you can check for stamped indentifiers on the steel housing. Scrape off the rust and grease and read the stamping.

FYI and very important: do not mix short and long on the same axle!

 

A longer stroke brake pot cannot over cam brakes. The only way to over cam a brake is by severely worn brake shoes or drum.