Hydraulic trailer brakes

[Mitch schiffer]

I just picked up a bigger trailer and I currently has non functional air over hydraulic drum breaks. Im wondering if anyone has experience with the electric over hydraulic systems. I need to convert it to just electric or electric over hydraulic. The hydraulic is more expensive but I may be able to use some of the existing parts.

[Bill Dufour]

https://www.etrailer.com/faq-Adding-Electric-Over-Hydraulic-Disc-Brakes.aspx

https://www.easternmarine.com/electric-hydraulic-brake-actuators (https://www.etrailer.com/faq-Adding-Electric-Over-Hydraulic-Disc-Brakes.aspx)

[Tom M King]

We have the Dexter actuator on a horse trailer, and it's been troublefree. I do keep that trailer under a shed, and never put anything on the road when there is salt added.

I was going to recommend the Brakesmart controller, but I looked for a link and see that it's no longer on the market. In any case, I'd recommend one that is not inertia based. The Brakesmart tied into the hydraulic system of the master cylinder, and made the rig act like one unit with ideal braking co-ordination.

I did find this one that is supposed to work the same way, but it's electronic rather than mechanical. I didn't spend any time looking at it, or reading about it, but it seems to be highly recommended.

Proportional is what you want rather than inertia that depends on the truck decelerating first.
https://tusonrvbrakes.com/products/direclink-dl-100

[Kev Williams]

Back in the early '60's when my dad bought our family's first travel trailer, he had installed, what I would call anyway, a hydraulic-over-electric actuator, since it worked in reverse of electric over hydraulic- The trailer brakes were electric, but the actuator was plumbed directly to the truck's master brake cylinder, so the actuator operated exactly the same as the truck's brakes via actual brake fluid pressure. It mounted below the steering column, and had a 6" or so joystick. When you applied the trucks brakes, the joystick would move to the right, the more brake pressure applied, the farther the joystick moved. More movement equaled more voltage applied to the trailer brakes. To adjust the initial voltage you simply rotated the joystick, left less power, right for more. Easy to fine-tune trailer braking on the fly, and the stick was within easy reach of the driver, allowing you to apply only the trailer brakes. I got to tow my parents 4000# Aljo travel trailer not long after getting my drivers license, first time I towed anything, and other than hearing the initial 'clack' of the magnets grabbing the brake drums, the truck/trailer combo slowed and stopped exactly as the truck did by itself.

I've never come across a similar actuator since, and some just-now googling turns up nothing like it... Tom's description above is the closest I've heard of...

I've done a lot of towing but nothing with electric over hydraulic braking...

[Tom Stenzel]

Back in the early '60's when my dad bought our family's first travel trailer, he had installed, what I would call anyway, a hydraulic-over-electric actuator, since it worked in reverse of electric over hydraulic- The trailer brakes were electric, but the actuator was plumbed directly to the truck's master brake cylinder, so the actuator operated exactly the same as the truck's brakes via actual brake fluid pressure. It mounted below the steering column, and had a 6" or so joystick. When you applied the trucks brakes, the joystick would move to the right, the more brake pressure applied, the farther the joystick moved. More movement equaled more voltage applied to the trailer brakes. To adjust the initial voltage you simply rotated the joystick, left less power, right for more. Easy to fine-tune trailer braking on the fly, and the stick was within easy reach of the driver, allowing you to apply only the trailer brakes. I got to tow my parents 4000# Aljo travel trailer not long after getting my drivers license, first time I towed anything, and other than hearing the initial 'clack' of the magnets grabbing the brake drums, the truck/trailer combo slowed and stopped exactly as the truck did by itself.

I've never come across a similar actuator since, and some just-now googling turns up nothing like it... Tom's description above is the closest I've heard of...

I've done a lot of towing but nothing with electric over hydraulic braking...

My Dad had the same system in the 1964 Bel-Air wagon but I remember the controller being hooked to the brake pedal lever using a cable. There was also a box on the tongue that had a cable to that attached to some part of the hitch. If the trailer somehow un-attached itself it used the trailer battery to apply the brakes. If the hitch came off the car I don't know what would happen other than a lot of not good.

I remember replacing the magnets as the friction surface wore down. That was a long time ago.

-Tom

[Kev Williams]

My Dad had the same system in the 1964 Bel-Air wagon but I remember the controller being hooked to the brake pedal lever using a cable. There was also a box on the tongue that had a cable to that attached to some part of the hitch. If the trailer somehow un-attached itself it used the trailer battery to apply the brakes. If the hitch came off the car I don't know what would happen other than a lot of not good.

I remember replacing the magnets as the friction surface wore down. That was a long time ago.

-Tom
The electric brake failsafe for a trailer completely leaving the tow vehicle is a small 12v battery mounted to the trailer and a switch, that the cable you mention would be attached to in order to apply voltage to the brakes if/when the vehicles separated...

[Brian Elfert]

Back in the early '60's when my dad bought our family's first travel trailer, he had installed, what I would call anyway, a hydraulic-over-electric actuator, since it worked in reverse of electric over hydraulic- The trailer brakes were electric, but the actuator was plumbed directly to the truck's master brake cylinder, so the actuator operated exactly the same as the truck's brakes via actual brake fluid pressure. It mounted below the steering column, and had a 6" or so joystick. When you applied the trucks brakes, the joystick would move to the right, the more brake pressure applied, the farther the joystick moved. More movement equaled more voltage applied to the trailer brakes. To adjust the initial voltage you simply rotated the joystick, left less power, right for more. Easy to fine-tune trailer braking on the fly, and the stick was within easy reach of the driver, allowing you to apply only the trailer brakes. I got to tow my parents 4000# Aljo travel trailer not long after getting my drivers license, first time I towed anything, and other than hearing the initial 'clack' of the magnets grabbing the brake drums, the truck/trailer combo slowed and stopped exactly as the truck did by itself.

I've never come across a similar actuator since, and some just-now googling turns up nothing like it... Tom's description above is the closest I've heard of...


Maxbrake and Brakesmart both made a brake controller that had a pressure transducer that tapped into your brake system. Brakesmart also made one that worked with air brakes. I still have a Brakesmart in my motorhome that has air brakes. I had a Maxbrake in an F-350 at one point.

There is a newer brake controller called the Tuson DirecLink that interfaces with the OBD2 port.

Edit: Fixed name of brake controller by Tuson.

[Tom M King]

Brian, I also have a Brakesmart. When I looked for a link this morning, it looks like both Brakesmart and Maxbrake (a later variation by Brakesmart) are no longer on the market, but are still supported for parts. Mine is over 20 years old, and still works fine.

[Brian Elfert]

That is why I said made as neither appears to still be in production.

[Scott T Smith]

I have electric over hydraulic brakes on two of my trailers. One is a dual tandem 40’ gooseneck trailer, and the other a 23’ tandem axle tagalong trailer with 7k axles.

LOVE THESE BRAKES!

The dual tandem axle has Hyd disk brakes, the other is one converted from hydraulic surge drum brakes.

The master cylinders are easy to add and work with a standard electric trailer brake controller.

I highly recommend them.

[Mitch schiffer]

I have electric over hydraulic brakes on two of my trailers. One is a dual tandem 40’ gooseneck trailer, and the other a 23’ tandem axle tagalong trailer with 7k axles.

LOVE THESE BRAKES!

The dual tandem axle has Hyd disk brakes, the other is one converted from hydraulic surge drum brakes.

The master cylinders are easy to add and work with a standard electric trailer brake controller.

I highly recommend them.

Is there a big difference in the hydraulic drum vs disk between your 2 trailers?

[Ronald Blue]

What's the issue of the air over hydraulic brakes that you currently have. I have experience with them and they worked well on the heavy equipment. The air simply operated a master cylinder in the same fashion that your foot does in a normal vehicle. I changed out numerous air/hydraulic master cylinders. Usually the diaphragm ruptured and it was easier to change the unit.

[Mitch schiffer]

My truck isn't set up for air brakes plus the whole system excluding the breaks them selves are in pretty bad shape.

[Scott T Smith]

Is there a big difference in the hydraulic drum vs disk between your 2 trailers?

Much less fade on long grades with the disc brakes.

When loaded, the brakes on the trailer are so good that just using them (manual override on the trailer brake controller) will stop the entire rig in a reasonable distance.