Steel Soldiers::Military Vehicles Supersite - View Single Post

kendelrio · 05-06-2009, 09:25

This has not been spercifically addressed yet, so I figured I would throw it out.

Hydraulic safety is a huge concern with M/V's. Besides the obvious hazards of losing brakes to leaks, many of the vehicles have hydraulic rams and actuators on them.

Properly isolating the various components of the system will alleviate a lot of concerns, but remember, complacency is the most dangerous aspect of any job!

If you are using a hydraulic jack to raise your M/V, once it is in the air, place a jackstand that is rated AT LEAST to twice the weight being put on it. For instance, if you have an axle weight of 2,500 lbs and are lifting one side of it, 2,500/2=1,700 (weight on that side of the axle). Use a 2,500 lb jackstand. Anytime you are lifting, you want to use at least a 2:1 safety ratio, and NEVER get under a suspended load!

If you are going to work on a hydraulic ram, isolate the pump unit from the lines/ram and bleed the system to the resevoir. Most of these units use a load bearing valve called a "counter-balance" valve; they hold pressure. That is why on a forklift, you raise the forks and you don't have to hold the handle to keep it in place. On a system like this, it is **imperitive** that you keep in mind the fact there is pressure on BOTH sides of the lines (send AND return). Do not loosen a fitting that contains pressure! This can result in the fitting blowing off which will result in evironmental damage and possibly injury or death.

Never loosen fittings on system that has a load on it as this will result in the load falling.

Checking for leaks

Never ever use your hands to check for leaks. If hydraulic injection occurs, at the least, they will cut the affected area out, the next step is amputation of the finger/hand/limb. Worst case scenario is death. If you have a system with a suspected leak, use a piece of paper or cardboard (I use oil diapers) over the area with your hands clear of the suspected leak.

I've attached a .pdf file of one of our training modules for hydrauilic safety. While it references our ROV's, you can apply the lessons in it to any hydraulic system. I've also posted a great guide from Eaton for hydraulic system maintenance.