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Air Brake Issues

redneckchevy9

Well-Known Member
Joined
Sep 4, 2013
Messages
144
Location
Prophetstown, IL
Occupation
Draftsman/Boom Truck Driver
Today I locked up my rear brakes thanks to a nice lady that turned in front of me. I was going 60mph & when they locked, only the driver side left skid marks & nothing on the passenger side. I checked air pressure and all 8 were the same. So, do I have a canister going out or already out or what? Never locked the brakes up in this truck, but I don't think that is normal.
 

mitch504

Senior Member
Joined
Feb 27, 2010
Messages
5,776
Location
Andrews SC
did you check stroke on each?

If you have a restriction or longer hose on one side it can cause those brakes to come on just a little later. This is called "brake balance" in case you want to search for it.
 

FWD

Senior Member
Joined
Jan 6, 2009
Messages
289
Location
Barron County, Wi
you need to lay under the truck and have someone apply the brakes. The rod that comes out of the chamber is where you do your measuring. If it is a type 30 chamber, which it probably is, then from when the brakes are relaxed to when they are applied, the distance has to be less than 2". That's where you have to start. Bad cam bushings can cause this problem along with miss matched hoses. Miss matched brake shoes could be another problem.

FWD
 

Dad5

Well-Known Member
Joined
Jan 15, 2011
Messages
79
Location
Nova Scotia
Measure drum diameter as well. I have seen new drums that were out of spec still in the box.
 

redneckchevy9

Well-Known Member
Joined
Sep 4, 2013
Messages
144
Location
Prophetstown, IL
Occupation
Draftsman/Boom Truck Driver
Thanks for all the helpful things to check. Wish has a heated shop at work for this type of stuff, especially this time of year.
 
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