Hydraulics and Safety Bar System

[Angel-HILO]

Hello everyone,
I'm trying to wrap my mind around the HiLo trailer Hydraulic Lifting/Lowering design;
I sometimes wonder if the engineers did enough R&D testing on the hydraulic system back then to test and see if the system would hold up the weight of the top halve (which I suspect is at least 1500 lbs and upward on most HiLos) for a substantial amount of time, say...a week or two, and then check it for any slow downward creep and settling onto the safety bar. I think they figured when testing that if it stayed pressurized for a few days and not settling on the safety bar that it's an acceptable performance.

I have used and owned a lot of good quality hydraulic floor jacks that after a number of days holding up a HEAVY load they would leak down a little and lose some height. Most systems do.
If HiLo designed and intended the pressure in the Ram and the hydraulic system to stay up pressurized in a fully extended position for an extended period of time, and NOT creep downward onto the safety bar; then WHY for so many years have HiLo owners had problems with the top halve slowly settling on the safety bar?? Apparently the newer Hilos also leak down onto the safety bar after a few years of using their HiLo. I realize that hoses, seals and fittings get old and
will eventually start to fail, I think an additional mechanical locking system would have been nice, that way most or ALL of the top halve weight would be resting on it, relieving all the pressure off the hydraulics. Just my thoughts.

 

[DunhamsDen]

To Bar or not to Bar

The truth is, hydraulic valves and check valves DO leak. They are not perfect. And have you seen the line feeding the cylinder? On mine it's plastic. The bar is part of the design. That's what it is there for. For that reason I always lower mine on the bar whenever I raise the top.

 

[Angel-HILO]

DunhamsDen, when I first got my HiLo I too would lower mine onto the safety bar after fully extending it. Now I extended fully and let it settle onto the safety bar on it's own; which happens in a couple of days. I haven't found any leaks visually, and if it's supposed to stay up and off of the safety bar...then I have a small undetectable leak somewhere. I can live with it.

 

[DunhamsDen]

Not a real problem.

These systems have been proven over many years of service.

If you see no signs of leaks, most likely the check valve is slowly leaking back into the resevoir. Don't worry about it as long as you do not have to add fluid.

 

[Seanpk]

I have recently purchased a 88 Funchaser and gutting to the bare structure as it is water damaged. The hydraulic motor is working when I run jumper cables to the battery from my truck, so I guess I need a new deep cycle battery. Where do the safety bars go?

 

[Angel-HILO]

Seanpk,

The safety bars are factory installed underneath the trailer by the hydraulic ram. They are there in case there's a sudden loss of hydraulic pressure in the system. The upper halve would come to a rest on top of it if that was to happen.

Hope this helps.

 

[NTL1991]

As a new owner of a Hi-Lo, I assumed I was supposed to lower the roof back onto the safety bar, much like when lifting a vehicle on a 2-post hydraulic lift. I realized though, that the upper belt molding around the lower half is much too high to make contact with the top half seal when the roof is resting on the safety bar. So up it goes until the pump "whines" as the manual states, and the seal is perfect again. After a couple days up, it will settle down. Up it goes again to ensure a good seal. That's at least how I do it.

 

[JackandJanet]

You're doing it the right way, Nick! The safety bar is just that - a "safety" protection.

- Jack