Read several posts and just curious if it can be done. I'm going to be moving and would like to back the trailer up my inclined driveway. It is fairly steep, probably in excess of 15% grade. I've never tried it. The trailer will be a uhaul 6x12 which is equipped with surge brakes. If i understand it correctly, surge brakes are triggered by a shift in the trailer's momentum orward upon braking. What I don't know is how much it takes to trigger this. If I back up the incline slowing and steadily, will they engage? Once on the hill will they engage and lock to where I'll encounter difficulty driving the trailer out?

It may sound like a silly question, but at least I can back a trailer! I was at the Uhaul place and watched two guys drive into a dead end which required a straight reverse of about 40 feet. I think it was 8 tries before they got it out. Even the Uhaul guys noticed it and said they wished they could require a trailer skills test before turning people loose.

 

My jaco tent camper has surge breaks. There is a lock on the tunge to stop the breaks from working when I back up.

 

There should be lock-out pin or lever, be sure to ask the agent about it as he may think you already know about it
Mine has a lock-out pin and it automaticaly resets when going forward

 

I have had two trailers with surge brakes. If your system already has a built-in lockout, that is great, but neither of mine did.

First, let me guarantee that you will sooner or later find out that backing is a problem with surge brakes. I learned this early with a 5,000-pound sailboat on a tandem-axle trailer. I had a rather steep drive-way, up from the street, into my level back-yard. The first time I decided to back it in, I noticed that I was fighting the surge brake when I backed up-hill.

When in normal use, it is the momentum in the trailer that produces the force that applies the trailer brakes when the tow vehicle's brakes slow it, causing the surge brake to "telescope" and actuate the master cylinder. When backing up-hill or over any obstacle, the surge brakes may start to actuate. Once the brakes start to actuate, they will grab and set up hard. In my case I could push the trailer up the driveway. With brakes only on one axle, I left skid marks the whole way. I planned on adding brakes to the other axle so I new I had to "fix" this problem.

If your brakes are disks, they may have less self-actuating effect and you may be able to overcome them. There are "free-backing" drum brakes which have both shoes set up in "leading" fashion. (These are not common, so if you do not understand, do not wory too much.) Most drum trailer brakes have both a leading and a trailing shoe and are self-actuating in both directions - this is why we have backing problems.

I did not want to fight my brakes every time I came home, so I used a simple solution that was quite effective for backing up when you have the time to manually apply a lockout. (Lockout systems that require you to get out of the vehicle are fine, but they will not be much fun if you are suddenly put into a situation out on the road where you have to back up. I'll do a follow up post to discuss non-manual lockouts.)

My "system" counsisted of a small piece of hardwood flooring and a large "C" clamp. The hardwood was trimmed to fit in between the outer piece of rectangular steel tubing that comprised the body of the telescoping system, and the pair of pins going through the inner rectangular steel tubing. The "C" clamp held the block in place. This approach applies to significant portion of surge brakes. I used my manual lockout too many times to count.

In general, all you need to effect a manual lockout is anything that prevents the mechanical motion required to set the surge brake. I planned on making up a pin which would be inserted into a hole drilled all the way through both both pieces of rectangular steel tubing, but I never did get around to it because my "kludge" system worked well. The best place to drill these holes without weakening the coupler is at the middle height position through the vertical walls - a half-inch hole should be adequate - the pin could be an 8" long grade 8 bolt. You need to make sure you do not hit anything when drilling, so a dis-assembly is required. If you do not feel comfortable with doing this, please seek another solution.

 

The next level of locking out surge brakes is to install an electric solenoid valve between the surge brake master cylinder and the rest of the trailer brake hydraulic system. This valve must be designed for hydraulic brake installation and, while they are not easy to find, they are available through RV-supply outlets. Another source is the "line lock" used by the hot rodders to assist in holding position at the starting line of a drag race. (Also some Chrysler products actually used a hydraulic solenoid valve to lock the service brakes for parking, but you didn't hear that from me in an FTE post.)

Most solenoid valves will be normally open and you will need to run another wire back to the trailer to energize the valve when backing. A momentary switch would be best because you do not want to forget and have your brakes locked out when going down the road. If you want to use a regular toggle switch, I would suggest a bright light and/or a buzzer to remind you to turn the lockout off. This system is "fail-safe", meaning that should a wire break, the solenoid is open and you have functioning brakes.

Finally, there is an option to provide automatic operation. If you can find a normally closed solenoid valve, it can be hooked to the brake-light wiring already in your trailer, so no additional wires are required. The only time the surge brakes should actuate is when the tow vehicle's brakes are actuated, which will open the solenoid valve, allowing the surge brakes to work. This system would not be fail-safe, but remember neither are electric trailer brakes which depend on a single wire as well.

I have purchased the solenoid valve, but at this point am still using my manual lockout. I would be interested in others' experiences and opinions.

P.S.: I experienced a high speed fishtail and rollover accident with my second trailer. I still tow the same trailer, but NEVER do I allow the trailer weight to be greater than the tow vehicle weight. If I had not had surge brakes, I could have applied the trailer brakes and damped out the fishtail before it got wild. I still like surge brakes for some applications, but my two vehicle is now an F-350 and I will be building a fifth-wheel trailer which will NOT have surge brakes.

 

Archie -

Another solution would be to install a 5-pin flat connector along with the solenoid. If it's wired correctly and you used a 7-into-5 adapter, the surge brakes would be shut off anytime you shifted into reverse (power comes from the TV's center pin on the 7-pole). My 24' 'Toon has this set-up and makes backing a lot less of a hassle.

My only concern about using a normally-closed solenoid is, after long idle periods, it might become frozen and not open just when you need it most - JMHO.



Steve

 

Steve,

I agree with your analysis. If you have backup lights, the extra wire to the solenoid can be hooked to them, then you have a reliable AND automatic system. Trailers lead a tough life, sitting up, ususally outdoors, for long periods. A once-a-month short trip would keep a lot of them from having so many maintenance problems.

I just thought of another manual system: Use a small high-pressure ball valve right behind the master cylinder. You would still have to leave the driver's seat, but it would be cheap AND reliable. ("Automatic" version: have a passenger trained to run back and operate the valve!)

 

> The trailer will be a uhaul 6x12 which is equipped with surge brakes.

I rent these frequently, both the open and covered, so I can answer with 1st hand knowledge.

> If I back up the incline slowing and steadily, will they engage

Most likely, the vehicle will feel like it is bucking, they will also engage going down a hill while trying to turn, off road, if the vehicle stops at all.

> What I don't know is how much it takes to trigger this.

Not much.

The U-Haul comes with a disengage lever (that pushes directly on the mstr cyl) noone ever uses, as such it is rusted into place. I made the mistake of moving it by hand and it nearly broke my forearm when it snapped free. I had to triple check it for a compound fracture as I couldn't feel my arm.

I would suggest using a long screw driver or breaker bar to avoid personal injury to pry it up and keep body parts out of the way. If it snaps up and you are in the way it has enough pressure to break something. fwiw

Bring something to turn the **** for the hitch ball. Once it is screwed down tight, it is impossible to turn again by hand with the lockout tab engaged. I bring a pair of water pump plyers. Sometimes I have wacked it with a block of wood (chock).

 

rebocardo,

Sorry I fooled you by reviving this old thread, but I thought it would be a chance to put out some useful info. Your info is good too, but I think he returned the trailer to U-haul by now . . .

 

Funny - I always thought of them as: "U-CRAWL" trailers