Use Of Hydraulic-Electric Brake Controllers on Dodge Rams

[HBarlow]

For anyone who remembers the days when we used the old-fashioned hydraulic-electric brake controllers made by Kelsey-Hayes which tapped into the tow vehicle's brake system and is afraid to use one of the old fashioned brake controllers on a modern Dodge Ram, this post is to advise you that it can be done.



SRehberg started a post recently in the Towing, Hauling, and RV forum titled "brake controller" in which he asked if it is possible to tap into the complicated brake systems of our four-wheel ABS equipped Dodge Rams and use one of the old style brake controllers.



I knew that it could be successfully done on a '94 Ford F250 with two wheel ABS but was not 100% certain it could be done on our Rams. Besides, I had been unable to determine a source of a tee fitting that would permit tapping into the system. The posts by several members on SRehberg's thread encouraged me to pursue the issue.



I learned that a NAPA p/n 7921 "towed vehicle fitting" available at any NAPA store for $6 will fit my 2001. 5 Ram with four wheel disc ABS brakes.



Today I tapped into the brake system of my Ram and installed the old Kelsey-Hayes brake controller. I tested the truck independently to ensure I had not introduced a problem then tested the truck and trailer brakes pulling my 8,500# Avion. The old-fashioned brake controller caused no problems I could detect with the factory ABS brakes on my truck and when towing, the trailer brakes worked in a perfectly smooth and modulated manner as if the truck and trailer brakes were connected by a common hydraulic line.



If anyone is interested in reading more details, see my post on SRehberg's thread on this forum titled "brake controller. "



Harvey

 

[Bill Stockard]

Thanks Harvey!



I have been thinking about installing a brake controller on my '03, but have not been impressed with any of the gee-whiz electronic models that everyone says we must use. Since I haul and don't tow, I haven't been in a big hurry to install one; however, I could have used one on my truck last week when I towed a 34 foot, triple axle, '87 Avion for a TDR friend through 5 PM traffic in downtown Fort Worth on I-35W.



I think I will go dig my old Kelsey-Hayes Modular IV out of the trailer junk box, dust it off, and try hooking it up with the NAPA fitting. The factory furnished pigtail should work fine for the electrical connections.



Bill

 

[Paul Herioux]

The reason these type brake controls aren't supposed to be used with anti-lock brakes is what happens when the antilock activates.

On the RWAL systems you are normally tapping into the line between the master cylinder and the RWAL valve. When the system activates the first thing that happens is the isolation valve closes. This causes the line pressure between the master cylinder and RWAL valve to spike. This increase in pressure causes the brake controller to go to full apply on the trailer brakes. Do you REALLY want full trailer brakes when trying to stop on ice or loose gravel????



On 4WAL systems and RWAL systems where you can tap in after the antilock valving the effect is somewhat reversed. The brake pressure is constantly fluctuating, mostly going down, during anti-lock operation. This may cause trailer braking to decrease if the brake controller can keep up with the rapidly fluctuating pressure and not have a siezure. When the brake controller does change trailer brake apply it may not be in corralation with what you actually need.



The other real draw back when hooked into a 4WAL system is that the controller is only hooked into one of the 3 or 4 circuits on the truck. If you hit a patch of ice with the tire that the brake controller is hooked to nearly all pressure from that circuit will be dumped. This will cause the trailer brakes to release(or be knocked back to a very light apply), not a good situation if you are rapidly closing on the accident ahead of you.



The last point I will make on this is: Do you really want to take a chance of the dirt and old fluid from that nasty 20 year old controller getting back up into a $1000 antilock brake unit????



Just my profesional opinion,

Paul

 

[HBarlow]

Originally posted by Paul Herioux

The reason these type brake controls aren't supposed to be used with anti-lock brakes is what happens when the antilock activates.





Paul:



Where is that statement written? It would be beneficial to TDR members who might be contemplating dusting off their old hydraulic controllers and reinstalling them in their Dodges if you would provide a reference or post authoratative documentation to prove the validity of that statement.



Three years ago I spoke by telephone with an engineer at Kelsey-Hayes now Hayes Lemmerz or Lemmerz about using the hydraulic controller on a rear wheel ABS equipped truck. He would not put his comments in writing for obvious reasons but he stated that there was no mechanical reason that I could not use the hydraulic controller with ABS systems. I believed him and installed the controller in a 1994 Ford F-250 with rear ABS and used it for approximately 30,000 satisfying towing miles. That Lemmerz employee had no reason to tell me that other than it was his honest opinion based on his work with the controllers. His company offered at the time, and still sells, several excellent electronic controllers.



As recently as three years ago Chevrolet's new truck brochures included a line stating that a brake controller that tapped into the tow vehicle's hydraulic brake system COULD BE USED as long as the brake controller did not displace more than 0. 02 cubic centimeters of brake fluid. The Lemmerz engineer I spoke with and the literature that came with my hydraulic controller clearly states that the K-H controller displaces less than 0. 01 cubic centimeters of brake fluid.



As I wrote in my post, I am not interested in convincing anyone to replace their electronic pendulum or cable actuated controller. Likewise, I can assure you that you will not persuade me to use one again.



Harvey

 

[Paul Herioux]

Harvey,



I got this information from a Chrysler engineer 10 years ago. I was working for a dealer at the time and had a 91 Ram come in with repeated antilock valve failures. The gentleman had taken the brake controller off of his 73 Dodge and installed it on the 91 shortly after purchase. The reason for the repeat failures was contamination from the sediment built up in the 18 year old brake controller and its plumbing. No more problems after taking the brake controller off and flushing the system. This was back when Chrysler still had field engineers in their zone offices and you could get one into the dealership in a couple of hours for the really wierd problems. This was a face to face conversation so there is no written documentation.



Time to go to work, I have cars to fix,

Paul

 

[Bill Stockard]

Just thinking out loud here... I'm not condemning any statements by Paul.



Written by HBarlow in another post about his K-H brake controller installation, "I routed a six foot length of NAPA brake line through the firewall and connected it to the tee fitting and the brake controller". I assume this means a new brake line from the master cylinder to the brake controller. With the brake controller displacing less than 0. 01 cubic centimeters of brake fluid, how can dirt and old fluid contaminate the brake system?



My K-H Modular IV brake controller has been stored in its original packaging since it was removed from my previously owned Ford F250 in 1992. The brake fluid has been drained from the brake line and capped with the original plastic caps; therefore, contamination shouldn't be a problem.



I DO NOT drive on ice so that isn't a concern. The one or two times a year that we have icing conditions in north central Texas, I do not get out on the roads with the "crazies".



Why am I messing with a brake controller ... I don't even own a trailer with brakes on it!



Bill

 

[Un-Hemi]

The educated opinion of myself and my diesel-truck-mechanic-bud is that a Kelsey-Hayes hydraulic controller wouldn't have any effect on, or be affected by, my '99's rear anti-lock brakes. I was all set to install it until Eric_77 in another recent thread mentioned.....



http://www.masterbrake.com/



... . and my plans changed! This unit uses a pressure sensor on the master cylinder that is wired to the controller, eliminating the hydraulic line into the cab. It's also capable of running electric-over-hydraulic and air-over-hydraulic systems. It's also much more expensive than an ancient hydraulic controller.



Anyway, in the process of cleaning up the K-H hydraulic controller in anticipation of installing it, I easily disassembled the tiny hydraulic cylinder in the controller and cleaned out what muck there was from its long-previous install. I would have no qualms about installing it - if I so chose.



My preference is to mount the controller to the left side of the driver's seat, so it is in easy reach; with a hydraulic controller, a flexible hose would be required , adding to the complexity of the install. The Masterbrake install will be mucho easier, albeit more expen$ive. :{



YMMV, etc.



Tom