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ANYBODY WHO HAS EVER PULLED A TRAILER OF any size or land lias likely muttered something to the effect of "Whoa, big fella" at one time or another. Lets face it; typical trailer brakes are relatively old-school engineering. They're drum, operated by electromagnets, and frequently slow to apply or all too eager to lock up - although this is often related to the controller.
Disc brakes are the partial answer, and powering them via hydraulics helps complete the picture. Use of such technology represents quite a leap, but it's not as far-fetched or complicated as it once was. Indeed, it's become a factory option on some trailers, and a viable upgrade for older trailers.
PARTS IS PARTS
Tow BRAKE INTERNATIONAL HAS DEVELOPED A KIT, available for most common trailer axles and wheel-bolt patterns, to convert older frailer brakes to hydraulic discs. The Tow Brake system can be easily installed by a backyard mechanic in a weekend, a point we proved by doing it ourselves, and the only "specialized" tool required is a flare-nut wrench for the brake-line fittings; a vacuum pump is included in the kit.
This is not the first such kit on the market, although the manufacturer claims that its Tow Brake system reaches maximum pressure faster and features a higher maximum pressure than the others.
System component delivery came in multiple boxes, and included paintedfor-corrosion-protection vented rotors; calipers; the HD3000 actuator engine; new bearings, hardware and fittings; more than adequate lengths of wiring and brake line for our subject fifthwheel; and a 24-page installation and operations manual. The only items we required that were not included - DOT 3 brake fluid, axle grease and cotter pins - are standard workshop supplies. We noted that, except for the actuator, none of the parts appeal's to be a "one-off design, so you should find replacements at your local parts vendor. That is, assuming you ever wear anything out.
THE TEST DUMMIES
THE TRUCK AND TRAILKR UNIT WE used was chosen to approximate an average combination in use (not a showroom-fresh model) - one that is driven on a regular basis so we'd know if our "baseline" results were out of the ordinary. The tow rig was a 1998 Dodge 2500 diesel weighing 7,500 pounds as tested (and larger-than-stock off-road type tires), and the trailer was a 1992 Alpenlite 30-foot dual-axle fifth-wheel that weighed about 9,000 pounds. The trailer is used and serviced routinely, so although the design may have been older all the parts were in good condition ... there were no missing shoes, springs, wires, and so on.
First we ran the truck with two occupants and performed a few measured braking tests. The truck provided average 60-0 MPH braking of 193.5 feet on the test surface (the exhaust brake was not utilized for any tests). We then attached the trailer and warmed the brakes on it by driving for several miles in city traffic. The tests of the combined unit provided a best 60-0 MPH braking distance of nearly 350 feet (remember that travel trailers do not yet have, the antilock braking systems featured on most recentmodel pickups). A test of brake fade showed that the brakes quickly heated and stopped supplying any significant braking power on a long grade.
GETTING DIRTY
WE UNDERTOOK THE BRAKE swap fully expecting to run into delays because the system is a generic application designed to fit as many installations as possible. To further complicate matters, we did the work in an RV storage lot with no acuities of any kind, using only normal RV-type tools. First, we removed the old system down to the axles. The wiring was completely hidden inside the confines of the trailer, except for the 12 inches or so at the axle. We removed and capped as much of this as we could.
The backing plates, seals, bearings, rotors and calipers went together perfectly. The only way it could have been any easier is if somebody else did it. The rotor diameter is close to the maximum that could be fitted in the wheel, and thick enough to allow them to likely outlast the trailer. The brake pads will probably never have to be replaced; however, just in case, they have wear indicators that'll squeak when they're wearing low.
A rubber brake-fluid line attaches to the caliper to permit movement without damage. Steel lines run from each axle to the on-board combined actuator/master-cylinder unit. We firmly attached this unit in one of the storage boxes, where it took up less room than we had feared. The actuator has just five wires to attach - simple work by following the directions. The only sticking point on our example was that the emergency breakaway switch was positive and the new unit required it to be negative. A quick re-wire and all was well.
As always, filling and purging the system took time and patience. Since each of the lines was about 20 feet long total, it did take a while, though the supplied vacuum pump sped the process. When finished, the trailer looked the same as it had before, an indication that we had not screwed things up too badly. Tow Brake provides a sticker to be placed someplace conspicuous to let people know the trailer has hydraulic disc brakes, so we placed it on the drivers side of the pin box. We then hooked up the truck to the trailer and we were ready to take a test drive.
LOADING BASICS 101
THE DIRECTIONS STATE THAT YOU should make sure to secure everything in the trailer. We'd gotten so relaxed about even needing the directions we somehow overlooked that part.
Since the new rotors are completely painted and we had no intent of sanding the paint off, we drove around and made lots of easy brake applications to warm them up and remove the paint. We found that were you in an emergency situation, you could hit the button on the dash controller (Tow Brake recommends Tekonshas Prodigy, although, for consistency, we used an older unit already in the truck) and lock the trailer brakes in less than one second. We experimented with settings to get to a point where firm brake-pedal application provided great braking and no lock-up, so complete control was maintained. We also checked the wheel bearings with an IR thermometer to ensure none were improperly adjusted.
The time had come for the "after" test. We went to our favorite stretch of roadway, now sporting some distinguished rubber marks, and did some more tests. Our test showed 60-0 MPH distances of approximately 250 feet for the truck and trailer - more than 100 feet shorter than with the original brakes, and only about 60 feet longer than the truck alone. Although drumbrake design has changed little since this trailer was built, a new trailer and brakes would not show quite the same improvement. On tests for fade, there was none that was measurable. The feel in the truck was incredible.
We then returned to the lot for some follow-up. We found that we had not begun to wear the paint off the rotors, so a trip was planned with testing following that trip to be performed, and that the trailer rotors were immensely cooler than those on front of the truck. Also, we really should have heeded the warnings about securing items, as everything from baseball caps on wall hooks to the dining table previously secured to the wall had moved forward.
We performed the second set of tests after the rig had made a couple of trips, the pads fully seated and the rotors worn in and paint-free. At the same testing surface we recorded 60-0 MPH stopping distances of a little longer than 200 feet, only a few feet longer than the truck solo, and a major improvement that translates to an additional second of warning time at 60 MPH. Even better, the system does not ask any more of the truck's electrical system than the original brakes.
Installed, the system retails for about $2,150, with kits ranging from $1,398 to $3,476. The owner labeled this perhaps the best money somebody could put into a trailer-mechanical-system upgrade, especially for do-it-yourselfers, and in this case we're not inclined to disagree with him.
Tow Brake International Ltd., (800) 927-6778, towbrake.com. Circle 239 on Reader Service Card.
Copyright T L Enterprises, Inc. Feb 2005
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