Trailer bleeding brakes. Part 2

[demarko210]

This is my first shot at bleeding brakes the objective is simple, remove the air from the brake line. I purchase this item to do the bleeding. Port side bleed normal like I would see on youtube. Port side is the furthermost away from the cylinder. Starboard side was acting up. I am bleeding because this side locked up on me going to use the trailer to haul some wood. Disconnecting the caliper from the bracket I notice bad slider pins threads which damage the caliper mounting bracket on both sides. Purchase new pins and brackets and got them in. Grease the piston under the boot and slide pins as I put back on both sides.

When I bleed the starboard side I did not get any fluid out at all. I was convinced that I need to replace the caliper. I would pump the actuator while the valve was open pulling air and still not fluid would come out. Again thinking I was going to need a caliper, I pulled the valve all the way out and saw the bottom hole was clogged. I stuck a screw in and freed up the hole but I did not have anything to really clean and blow it out at the time. I put the valve back in and tried to bleed again. Now I am getting fluid but with a lot of air. I bleed for about 30 minutes but the air bubbles would not go away from this side. As I bleed the caliper would lock and free up when I closed the valve but the air bubble remain.

I was thinking maybe replace the valve. Any ideas? I am going back over today and clean the valve out good and add some Teflon tape on the thread. I am thinking its leaking from the threads. Any ideas would be great thanks.

Tie down 46304 calipers. System was installed 2021. Hardly 1k miles on it.

 

[Scott Danforth]

This is my first shot at bleeding brakes the objective is simple, remove the air from the brake line.

Disconnecting the caliper from the bracket I notice bad slider pins threads which damage the caliper mounting bracket on both sides.

I am going back over today and clean the valve out good and add some Teflon tape on the thread. I am thinking its leaking from the threads. Any ideas would be great thanks.

First, have the master cylinder low (as on the ground) when you bleed trailer brakes

Make sure both calipers are in working order

Never use Teflon tape on any hydraulic connection. Teflon tape is for water systems.

 

[demarko210]

First, have the master cylinder low (as on the ground) when you bleed trailer brakes

Make sure both calipers are in working order

Never use Teflon tape on any hydraulic connection. Teflon tape is for water systems.

Setting at its lowest point.

Seems to be working both.

Thanks. I was unsure if Teflon would be okay. Looking at some thread sealant now.

 

[Scott Danforth]

Thanks. I was unsure if Teflon would be okay. Looking at some thread sealant now.

you should not need sealant.

the three types of fittings in the brake system are the bleeder which is a tapered seat, and the inverted flare nuts or crush washers in the lines. none need sealant.

 

[Lou C]

Sometimes the problem you can have with bleeding disc brakes is where the calipers are mounted on the mount in terms of location, if they are on the 9:00 or 3:00 position they may not be high enough for air bubbles to rise to the top. On drum brakes this is not a problem because the wheel cylinders are always on the top of the backing plate higher than the brake lines. See if the mounting bracket allows you to mount the caliper higher up. I have always had drum brakes and never had trouble bleeding them with a little Lisle one man bleeder. Make sure the master cyl does not run dry when bleeding.

 

[dingbat]

If the bleed port with clogged with junk, hard telling the condition of the caliper internally.

What did you do to "grease the piston"

No way to get air in the system unless the actuator is low on fluid, back up solenoid is leaking or you've loosened the bled valve(s) up too much. Shouldn't need more that just barely cracked.

Bleeder values block by tapered obstruction, not the threads. If it's leaking in the threads, the bleeder is either too loose or damaged

 

[demarko210]

you should not need sealant.

That thought occurred to me later in the day. As this is a part (bleeder) that should be movable.

 

[demarko210]

If the bleed port with clogged with junk, hard telling the condition of the caliper internally.

That obvious never even cross my mind. That was my decision maker to buy 2 new ones.

What did you do to "grease the piston"

No way to get air in the system unless the actuator is low on fluid, back up solenoid is leaking or you've loosened the bled valve(s) up too much. Shouldn't need more that just barely cracked.

Bleeder values block by tapered obstruction, not the threads. If it's leaking in the threads, the bleeder is either too loose or damaged

I just pulled the rubber piston boot up with a seal remover and add some of the brake lube in the area exposed.

I know how air got into the system. When I loosen the bleeder all the way i move the actuator while it was off to see if a hose was clogged. I was getting no fluid with the bleeder all the way up so I thought the a rubber hose would be clogged. Assuming when it released it sucked in air. But I think I may have had the bleeder off to far also. As I keep loosing it to the same spot and pulling fluid.

 

[demarko210]

Sometimes the problem you can have with bleeding disc brakes is where the calipers are mounted on the mount in terms of location, if they are on the 9:00 or 3:00 position they may not be high enough for air bubbles to rise to the top. On drum brakes this is not a problem because the wheel cylinders are always on the top of the backing plate higher than the brake lines. See if the mounting bracket allows you to mount the caliper higher up. I have always had drum brakes and never had trouble bleeding them with a little Lisle one man bleeder. Make sure the master cyl does not run dry when bleeding.

Drum brakes from what I was told wont hold up well in salt/brackish water which is why I went with disc brakes. Drum brakes seem more complicated to me but I could be wrong. Never worked on either. This is my first. My wheels are on a small hill with the axle on jack stands. The front is lowered all the way down.

 

[demarko210]

 

[Lou C]

from what I see there the calipers look like they are mounted too low for them to bleed easily, is it possible to rotate the caliper mount to put the caliper at the top? If not you could disconnect the caliper slide bolts, slide it up to the top of the rotor, bleed it and then re-install....might work....or, remove caliper and put a piece of wood the same thickness as the rotor in between the pads, lay the caliper on top of the frame rail, bleed it then compress the pads, remount caliper...it may be mounted like that because the caliper might not clear the frame rails if it was at the 12:00 position...
I do use drum brakes, galvanized with zinc coated drums, they work fine and last longer than non-stainless disc brakes around here. Drum brakes are self energizing vs disc brakes which are not.

 

[Scott06]

Sometimes the problem you can have with bleeding disc brakes is where the calipers are mounted on the mount in terms of location, if they are on the 9:00 or 3:00 position they may not be high enough for air bubbles to rise to the top. On drum brakes this is not a problem because the wheel cylinders are always on the top of the backing plate higher than the brake lines. See if the mounting bracket allows you to mount the caliper higher up. I have always had drum brakes and never had trouble bleeding them with a little Lisle one man bleeder. Make sure the master cyl does not run dry when bleeding.

Gotta make sure bleeder screw is on up side of caliper. Many time ( not always) they can be swapped side to side and bleeder may not be on up side of caliper.

i think the hose comes in on top instead of in bottom of caliper ? my tie downs were in same location. are you bleeding properly put pressure on the lever through slot in top then open bleeder will take many strokes to get fluid all the way to caliper . Crack line at master to see if you have fluid there first. With discs will be a reverse lockout valve is that flowing ok ?

when I bled mine I stroked the master with a big flat head and left a 4 ft cheater bar on it to keep pressure as I opened screw working alone … was not sexy but it worked.

 

[demarko210]

from what I see there the calipers look like they are mounted too low for them to bleed easily, is it possible to rotate the caliper mount to put the caliper at the top?

Yes I think I can. Here is what the manual says.

1. On a bare axle attach mounting plate to the brake flanges on the axle. Preferred position is at
“12:00” high or to the back side. Exact positioning will be determined by the brake flange. Use
7/16”x1-1/4” zinc hex bolts, lock nuts/washers and torque to 40 lbs.

I will mount the new calipers on the top if the brake hose does not get in the way. Being on top, what screw do you bleed from?

 

[demarko210]

I actually ordered a pair of Kodiak calipers back on the other post but I sent them back because I realized after I had them they will not fit the Tie Down caliper bracket. I am going to order a pair of the same calipers Tie down and order a rebuild kit for the old ones. The old ones I will clean and fix and place on my other boat trailer when I start the work on that trailer.

 

[demarko210]

Also I was thinking since my tongue is at its lowest point and the wheels are on jacks the fluid will flow forward while air moves back. Maybe I have the tongue too low also.

 

[demarko210]

Went over this morning just to try and bleed again. I raised the tongue of the trailer a bit. Bleed the port first. Got a good stream no bubbles. Starboard side crack the valve and got fluid but not a steady stream. It was bubbly then i tighten the valve a bit and got a slow stream with no bubbles.

 

[demarko210]

Back at the trailer everyone. Got my 2 new Dexter calipers 46304 in last Friday and went over yesterday to install them and here is what happened. Removed the bad caliper from the brake hose. I did lightly strip the nut a bit and I notice the line did not even drip when I pulled it off. I went over to the good side (this side is the furthest away from the T-Fitting) to do the same without stripping the nut and the line constantly dripped when the caliper was off. Seems to be the 24" brake line connected at the T-Fitting. Once they both were off I press the piston in on both calipers and they were full of fluid. I ordered a hose this morning now I am debating on getting my $300 back for the caliper since it was only the brake hose.

With that being said when I had the brakes installed the 24" hose was put in with a loop below the axle and frame. Same picture as above. I think this is what cause the issue of the hose callasping. I will try to keep the new hose on top of the frame and only flow down to connect to the caliper. Next post should be the test drive.

 

[Lou C]

A delaminated brake line can stop the return flow of brake fluid and fool you into thinking that the caliper is sticking when it’s not.

 

[bruceb58]

You need a small loop in the hose. It allows the brake line to absorb the deflection from the suspension. You do NOT want it on the top of the frame

 

[ESGWheel]

Sorry for being late to the party but here are a few thoughts for consideration.

• An internally collapsed hose is not a result of the routing unless it was an extremely tight bend or exposed to road damage. It may have simply failed.
• The picture of your hose seems to have too much play and is low to the ground which may have exposed it to road debris damage
• And just to be sure: while the word “loop” is being used it does not mean a literal loop like a roller coaster going upside down. It simply means enough play in the hose to account for the suspension movement + the in/out of the caliper which is critical.
• They make hoses with a 90 bend at the caliper end (link) that you can use to get the hose back to the axle with enough ‘play’ to account for the needed flex. Alternatively, they also make a 90-degree fittings to accomplish the same thing. The key here is to get it to look like the below mockup. And since you have a torsion axle more play than my mockup represents is needed.

I have the same bleeder device you do that creates a vacuum and have used it successfully. However, IMO, nothing beats creating pressure with the actuator (aka master cylinder) and cracking open the bleeder screw. I use the actual trailer hitch ball mount I put in my truck for this. Lock the ball into the actuator as if you were going to tow and now have a lever that can push down on to create the pressure. I have someone do that while I am at the bleeder screws cracking them open. I have them pump up the pressure 2 or 3 times and keep pressing down on the last stroke and then crack open the bleeder no more then a 1/4 of a turn and then close bleeder prior to helper releasing pressure to stroke again. So it’s a quick open/close. Repeat until no air. I use the vacuum device with the hose connected to the bleeder as a collection device as well as being able to see any bubbles in the clear hose. Note: use the closed end of the wrench for this process > just put it on prior to putting on the hose on the bleeder.