Hello, I am wondering what adverse effects could be expected from using generic ISO rated hydraulic oil (32,46) from a farm supply store in place of manufacture specific oils? My employer is always looking to save a buck and often I am told to just fill it with aw46 when for example the JD backhoe recently in the shop called for hygard engine oil in the hydraulics, or the Lull loader called for Mobilfluid 424 tractor fluid in the hydraulic system. Would an oil specifically designed for hydraulic systems not be a better choice? Obviously the oils stated in the manual are there for a reason, I’m just trying to better understand this.
Is this your employers equipment or a customers machine? Customer might be a little ripped to find out that you filled his $250k machine with oil from Joe's Gas and Groceries. In general farm store brand oil is not highly rated. Employers machines - well it's his money and he pays for repairs so if he wants to risk it -his choice. There a very good competitve substitutes for many oils if you check specs and certifications. Take some work, but you don't always need what is in the manual. In general though good oil costs about the same from any brand. Comes down to brands you can get close by. Avoid anything that says “also recommended for” or things like that.
Depending on the machine could have major issues if the oil doesn't meet OEM specs. Hygard and similar oils aren't standard hyd. oils. They are designed for multi applications like transmissions and differentials in addition to hyd's.
It depends on the machine and what system you are putting the oil in. If you are working on an old fork lift with a gear pump and only a couple of cylinder functions, then any AW46 will work. If you are working on a couple of year old excavator with axle piston pumps and motors and a load sensing system, then you had better be a little picky about what you put in there.
hygard is not engine oil. also, the hygard is compatible with wet brakes and clutch packs whereas straight hyd oils are usually not.
Hy-gard is often referred to as "tractor oil" which like 56wrench says is not just plain hydraulic oil. It is designed to work with differentials, transmissions, wet clutches and brakes. Do not substitute with plain hydraulic oil or you could mess up any clutch/brake linings and worst case lose brakes. ISZ