I need a education on trailer brakes

[Magard]

The trailer is a 1993. I believe it’s pre abs.

[JMBT]

If the brake chambers are old they may be leaking internally. That can cause the brakes to be grabby by slowing release time of the chamber. You can take off the emergency line at one canister and have someone press and hold the brake pedal, put your finger over the hole on the chamber where you removed the emergency line and see if you feel air. Check each chamber the same way.

[MCRENT]

I had an issue with 1 wheel locking up on my step deck, Replaced all the shoes and and drums on the trailer, One wheel would lock up when empty. Replaced everything related to brakes. Ended up being the the shoes were arced wrong (manufacturing defect I guess) . New set of shoes and problem solved. Bummer is I flat spotted brand new tires in the process.

[Brewster64]

If you are used to an ABS trailer you are gonna find a pre ABS a bit grabby, just the way it is. What you can do is flush the hell out of it( supply/ Emergency line only) with air brake antifreeze to make sure valves aren't gummy. They get varnished up from oil contamination. Then make sure crack pressure isn't more than a couple lbs lower than your truck service relay. IE: if the truck is 6psi, trailer should be no lower than 4. You can check that with # from valves with your local supplier. Probably somebody has put a low crack pressure valve back there because it looked right and fit, but they didn't really know what they were doing. Don't put a valve on your trailer that is a higher number than the tractor, you don't want that. Crack pressures on trailer service valves are designed so you get sequential braking and are great for overcoming that 50 or 60 feet of distance the service actuating pressure needs to travel. In Canada with all the trains running up here we see alot of guys having issues because guys don't really get this, relay valve is a relay valve mentality. Just a quick note on your "goofy" blue gladhand. That's a quick release valve, that makes your brakes come off quick. Lots of guy replace that with the $9.99 Truckstop special: DON'T. You won't enjoy that the first time you lock that pre and trailer up on ice. You should actually make sure that one stays there, as well as 2 on both lines on your tractor protection valve. I actually like an extra one midframe or back by the bogies on service side, especially on Midland Berg systems where there are 2 service relays on trailer, just gets those brakes back off in a hurry. One other thing to be aware of, especially on an older trailer is that I've seen guys put bigger brake chambers or longer slack adjusters on because we all know bigger is better. Unfortunately, this can lead to twitchy application as well as broken foundation brake parts( shoes, drums, cams, bushings, s cam tubes or mounting flanges) Also, if this is an air ride trailer, too high of a ride height and worn shocks can make er twitchy too! Just my 6.5 cents.