installing new brake calipers and break line.. bleeding?

[TNReb]

I am installing new calipers and a new brake line tomorrow. The only brake line I'm replacing is the one that goes from caliper to caliper - across the axle. I am not replacing the master brake line.

Anyone have any tips for properly bleeding it?

My thought is to connect everything, then have someone open the valve on the last caliper (farther from the master cylinder) while I hold the lever on the tongue and pump the thing with a screwdriver. Then have them close the valve while I release the thing and pump again (as they open it).

Once I've done that caliper, do I also need to do the other caliper? I'm confused on that part since the Dexter UFP caliper doesn't have an extra bleed valve (that "hole" is used to connect the brake line to the other caliper).

Is there any easier/smarter way I'm missing?

[Woody b]

Vacuum bleed them. You hook a pump to the bleeder(, with a reservoir attached to keep brake fluid from entering the pump,) and just pull the air out.

https://www.harborfreight.com/brake-...=&utm_content=


Just bleed from the one bleeder you have. To aid in getting the air out lightly peck on the other caliper, lines, ect to dislodge any air bubbles.

[TNReb]

Vacuum bleed them. You hook a pump to the bleeder(, with a reservoir attached to keep brake fluid from entering the pump,) and just pull the air out.

https://www.harborfreight.com/brake-...=&utm_content=


Just bleed from the one bleeder you have. To aid in getting the air out lightly peck on the other caliper, lines, ect to dislodge any air bubbles.

I thought about that also. Im still confused on whether to bleed only the last one or what. How would I bleed the first one since the bleed valve connects to the other caliper? Bleed it first, then connect it to the other caliper and bleed that one?

[mactlman]

start the farthest away and work forward. I used a few 2x4s and had my son push the tongue in and hold to bleed mine out when I did a fluid change was fast and easy. gravity bleeding first saves lots of time also

[TNReb]

start the farthest away and work forward. I used a few 2x4s and had my son push the tongue in and hold to bleed mine out when I did a fluid change was fast and easy. gravity bleeding first saves lots of time also

I guess I don't understand how to "work forward".

The closest caliper to the master has two fittings - one with the main line in, and another with a line that goes out and to the second caliper. The second caliper has the line in, and the bleed valve.

Do I only bleed the second caliper? I don't see how it'd be possible to bleed the first one. Since it's all one connection, it makes sense (to me) that I'd only bleed the last caliper.

[Woody b]

I thought about that also. Im still confused on whether to bleed only the last one or what. How would I bleed the first one since the bleed valve connects to the other caliper? Bleed it first, then connect it to the other caliper and bleed that one?

The way it's laid out you can start at the last one and get all of the air out. Since the bleeder location on the first caliper is feeding the second caliper bleeding the last/second caliper will get all the air out. Just lightly tap/peck on the calipers and lines occasionally to dislodge any air bubbles. Just use the vacuum pump until you think you have all the air out. Pumping the master cylinder will aerate the fluid and make it much harder to bleed.

[TNReb]

The way it's laid out you can start at the last one and get all of the air out. Since the bleeder location on the first caliper is feeding the second caliper bleeding the last/second caliper will get all the air out. Just lightly tap/peck on the calipers and lines occasionally to dislodge any air bubbles. Just use the vacuum pump until you think you have all the air out. Pumping the master cylinder will aerate the fluid and make it much harder to bleed.

Thanks for the explanation. I grabbed the vacuum pump earlier this morning. Shouldn't be too tough.

[TNReb]

Got the new calipers installed. Bled the lines until all the old fluid was out and the new was in.

Stupid breaks still don't work.

Might be a problem with the actuator, but I just replaced it last spring. I'm at a loss for what to do next.

Got a big trailer sales/service place nearby. Taking it to them next week. I give up!

[Cajunhunter67]

I put blocks of wood behind the trailer tires.
Hooked the trailer to my truck.
Leave the trailer light connector disconnect.
I would back up and until the brake master solenoid is compressed.
Engage the parking brake. Truck in park. Go to the caliper and open the bleed valve.
It will squirt out the oil just like bleeding brakes on a car.
Close the bleed valve before all the pressure is gone.
Disengage brake pull forward slightly. Allow surge brake to move forward. Top off reservoir and repeat until all air is out of system.
You will notice that as the air gets out the system it starts loading the brake calipers with pressure.
It’s a slow process but a sure way to get all the air out.

I have also used the pump for servicing the lower unit in a large brake oil container. Pumped it in a catch can until no air was present.
Installed the clear hose on the open bleed valve and pumped oil thru the entire system until it was coming out the reservoir. Put a catch can underneath to catch excess oil. Close the bleed valve before removing the clear hose. This worked quickly to remove air.
I then carried out the bleed procedure above. Brakes work excellent on the trailer.

Don

[krindgen]

I guess I don't understand how to "work forward".

The closest caliper to the master has two fittings - one with the main line in, and another with a line that goes out and to the second caliper. The second caliper has the line in, and the bleed valve.

Do I only bleed the second caliper? I don't see how it'd be possible to bleed the first one. Since it's all one connection, it makes sense (to me) that I'd only bleed the last caliper.

Sounds like your trailer has one bleeder at the left, front caliper. Phoenix was doing this also. Mine never worked right and I couldn't fully bleed the system using that one bleeder. MM sent me bleeders for the other three calipers and it worked better. Before that I noticed, even after going to a high dollar dealership, that I was only getting brakes to apply on one side of the trailer.

You might do better without the vacuum bleeder. It might work better to just use the master cylinder as your pump and push the fluid through. I seemed to have had better luck doing that instead of the vacuum bleeder.

[Bass Cat Boats]

We use a pressure bleeder ball to bleed all brakes.

BCB

[skeeterBill200]

Go on you tube look up Asian guy how to bleed boat trailer brakes. I did it myself works perfectly. Tools required is a medium screw driver 3mm socket wrench or brake line tool and extra brake fluid and ( maybe a syringe ). Which I didn`t use. Just remember to keep fluid high in filler so you don`t put more air in lines !!

[krindgen]

Go on you tube look up Asian guy how to bleed boat trailer brakes. I did it myself works perfectly. Tools required is a medium screw driver 3mm socket wrench or brake line tool and extra brake fluid and ( maybe a syringe ). Which I didn`t use. Just remember to keep fluid high in filler so you don`t put more air in lines !!

The bleeder hose has to be submerged in fluid so you don't suck air back into the system.

I think it was Asian Fishing Guy. Seems like he disappeared from YT.