brake line troubleshooting

[gdeangel]

I just took the mothballs off a 2007 single axle trailer with hydraulic disk brakes. The pads look ok, the disks have some rust, but before I get to changing them, I need some help troublshooting the brake lines.

So I openneed the master cylendar resevoir, and it was bone dry. I refill and, after screwing around with trying to actuate and bleed the brakes with my car and some wheel chocks, it took about 1/2 a bottle of fuild in the reservoir and there were some bubbles and it looked like it was going to make it through the lines, but then nothing ever came out of the bleeder valve-- it just started backing up and the resevoir overflowed a little. So I'm wonderring if the most likely culprit would be corrosion inside the lines due to air/condensation, vs an issue with something mechanical, like the master cylender, the calipers / bleeder, etc. There is no sign of corrosion or paint bubblling on the outside of lines. The calipers are a little dirty, and obviously not actuatinng without fluid -- so maybe a seal or something? I tried bleeding from both the farthest and nearest wheel... so intuition tells me it's either somewhere in the line upstream of the wheels or in the master cylendar.

I'm looking for tips and suggestion from anyone who might have dealth with a similar issue in the past.

Thanks

 

[alldodge]

With it being dry, it will probably take a bottle or more to bleed, also depends on what size bottle.

To bleed the brakes, take just the hitch and ball and place in the coupler. Use your hand to raise and low the coupler causing it to bleed. If you put the tongue higher then the wheels, gravity will cause it to work slowly. Loosen the caliper bleed screws and wait for fluid to exit.

 

[Thalasso]

http://www.championtrailers.com/techsup.html

Important.
Submerge the end of a hose in a glass container of brake fluid so that air bubbles can be observed.

Disconnect the trailer from the tow vehicle and hook the safety chains (NOT the actuator breakaway cable) together to form a loop. The loop should be centered below the actuators coupler.

Place a sturdy board such as a 2 x 4 into the safety chain loop below the coupler. The board should be four feet long or more so it will extend well above the actuator. Position the board to press against the front end of the actuator’s coupler and use it to force the coupler case into the actuators outer housing. This pumps the brake fluid into the trailer braking system. Manually pull the coupler case back to fully extended position and repeat the process.

 

[Alumarine]

I prefer AD's method. I find it simpler and easier and I don't need a 2x4.
I do use a short piece (18") of square tubing or something else to fit in the ball mount to give me more leverage.

Might want to remove the bleeder valves completely in case they're plugged up.

 

[Scott06]

as above you need to find a way to actuate the coupler. Some have a slot where a big screw driver will actuate the master cylinder, should be markings on it so you can look that units service manual up online.

You can try to bleed it but but I suspect it has sat dry and will be roached. I paid $500 for complete new system coupler hoses rotors and calipers. You maybe your time ahead starting with a clean slate.