Hydraulics - Loader

I blew a Hydraulic line on the weekend. This is a self contained unit, has it's own hydraulic pump attached to the front pulley.

I need help in two areas.
1. The little manual I got with this loader suggests to use Shawee Hydraulic oil. Can I use an off the shelf hydraulic fluid or might this Shawee hydraulic oil be some special oil?

2. This is the hard one. This loader has both up and down pressure. How do I bleed the hydraulic lines? There are no bleeder valves. Is there an article or something which describes this? I am familiar with bleeding brakes.

Any help is appracitated.

Boyde

Here is what I am going to do this weekend, I 'll report back with any results.

After studing the few pages of a manual that I have, in the trouble shooting page there is a mention of a "strainer". I will examine this rig again and see if I can identify where it might be, if I find one I shall clean it.

The relief valve is a ball, setting in a seat. I shall adjust the adjusting screw in and out and make sure I put it back to the exact location. If the spring is stuck, maybe this will free it up.

I shall replace the blown hose. Fill the resovior with a Hydraulic Oil ISO 32.

I shall loosen each coupling one at a time at the cylinder after applying pressure to that hose to expell any air.

I shall tighen everything down (double check), then cycle the cylinders, fully 6 times.

Then we shall see what I have.

Did I miss anything?

Regards
Boyde

The lift is slow and weak, while the down quickly drops and weak. Almost free fall, but controlable.

With the down pressure I used to be able to lift the front of the tractor, now it just tries.

Boyde

Does hydraulic fluid come in different weights or thickness?

I shall do the search you suggest.

Thanks
Boyde

If it will self bleed by rotating up and down a half dozen times then I must have another problem.

Here is the rest of my story.

I blew another hydraulic hose last fall. I replaced the hose, drained and replaced the hydraulic fluid, cycled the cycnlinders up and down a few times. I noticed that I did not have the power to lift and the speed that I had before changing the hydraulic fluid.

I figured it had to be air so this time I would bleed the hoses.

The pump feels like (in the seat of my pants) it is pumping too thin, like air.

Any thoughts or suggestions will be appreciated.

Boyde

Its likely the operating pressure is 1000 to 2000 psi and at that pressure a cylinder full of air compresses to a volume so small its no bother in the loader operation. And when full pressure is applied to one side of a cylinder with the other vented to the reservoir much air is moved out of the cylinder. It is possible to bleed the lines and sometimes the cylinder by loosening the hose connections at the cylinder, but its most practical to run the cylinder end to end a half dozen times and that will remove all the air that wasn't significant, effectively bleeding the system.

Gerald J.