Dear friends this site has helped me very much in the last year+ I've been coming here for advice. Youexperts told me how to get the cap end off of cylinders (torque and peening). Now the backhoe New Holland 555e (year 2000) is very herky-jerky in all hydraulics except locomotion- drives forward and reverse well. That's everything from steering to front loader and backhoe functions. Engine runs smoothly. Previous trouble of sudden loss of locomotion has been cured by flushing old hydralic fluid and cleaning cylinder screen at bottom of tranny. My Mechanic says we have air in the lines. We did rebuild the boom and extender cylinders with this sites help. Now we ask is their any known method to purge air from the hydraulics? We've cracked loose some lines, one at a time to hear and see some air spurting but a marked change was not noted. we haven't conducted a test point(s) pressure test as yet. Wondering if this site experts have an inside on this air purging procedure? Thank you
Sounds to me like the pump is sucking air. First check the level. If item #1 below (top pic) is clogged it cause the system to draw air in. Look at items #1 and #5 in the bottom drawing. Loose clamps or bad o-rings could also cause air in the system
I'm going now to look under with good flashlight. Have reported this info to my mechanic. He & I thank you, Mr. Swetz. OK, I just went to look at the backhoe underneath. My comparable to item # 2 in your lower picture is a 2 inch hose landed with two clamps on each end. The pump isn't wet from hydraulic oil although the fitting landed on the pump has been rough treated a bit. It's dented, but the clamps seem good. Hose is way denatured by the oil leaking onto it from the nearby 'manifold' of three(?) blocks. They are leaky as can be. They are fed from the top side of the pump ( also dry). This leaking has gotten worse over time. Now I see we gotta go in right there. I have some o-rings in a 'universal' kit. I see now that it's going to take some disassembly at the fitting/2" hose to then get access to the pressured lines to replace o-rings and tighten up. Will post progress. Thanks again, friend.
If the tractor is leaky, be sure the oil level is still up. Low level will cause the pump to get air in it. If you take the fitting off the bottom of the pump to change the o-ring, the tank will empty out on you!!. There is a plug in the bottom of the tank to drain it. If you drain it, I would recommend taking the cover off the tank and checking the filter. One of the members on here took that filter off and found a disc of sorts on it, blocking the flow.
Yes, sir that is our intent to disconnect after draining, and when hose, clamps and fitting are removed giving access to the block of what looks like three sets of diverters the bottom fitting on each are wet with fresh hydraulic fluid, from where much is wet in that nearby area I wonder if wrenching them off in a row, then rebuild each set of o-rings,working in a row to keep access as they are tightly packed together. If you have more to share, I am ready to incorporate your view.
Be very careful to compare the dimensions and profile of the OEM "O" rings that you remove to the universal ones you intend to use for replacements..
Imagine I will likely have to used the two kit of o-rings (one kit is the green ones) don't know if the fittings on the machine are SAE or Metric. Seems from the leaking I should have 1,2,or 3 sets to replace due to obvious failures on the feed side of the block diverters, the output sides are dry. Still seems very do-able for me and the mechanic. Almost have the damn tank drained, by hand pull plunger siphon pump 16 ounces at a time. Done 10 gallons, got a couple more to go. Looked at the drawing for filter connection method. Didn't show threads or clamps. I guess its push on to male pipe, nippled thru tank, as the outside is the 2 inch feed tube to the hydraulic pump. Trying to keep it clean(ish)
Here is a link to a thread that deals with removing the filter in the hydraulic tank. HeavyEquipmentForums Here is a pic looking in at the filter with the cover removed (hole on the bottom is the drain plug removed). As tinkerer said, be careful of the o-rings that you are using. Many times they are not standard metric or inch. It may be worth your while to buy them from NH. As for the fittings on this machine, they are ORFS, which is a flat face fitting with an o-ring. These are not the standard size. They do make kits with these special o-rings, like the one I linked below. https://www.ebay.com/itm/173242899836
How fast are you running the engine when operating the backhoe and loader? I find mine is hard to avoid jerking at anything above 1800 RPMs. I usually operate at around 1500.
Well, here's what we did; removing the 2 inch hose and flanged pump fitting required us to remove the small section of drive shaft in the way of the flange's hardware. I had drained the tank with a hand held suction tube (16 ounces per draw) 15 gallons worth. The nut end of the in tank filter is like over two inches, too big to get a wrench on it, and a strap wrench could not get it to budge. We decide to leave it as is. The bottom gallon seemed milky with water, the rest very fresh. we determined that the filter was working as it sits about two or three inches above the tank floor, pretty far above the milky fluid. While wiping off old fluid and observing I noted the new wet spot was coming from only one pressure fitting- the feed to the pump. We tested it for snugness before loosening it off, wasn't particularly tight, but not 'loose'. We went thru two kits to find an o-ring quite similar to the removed one. the flanged tube was rock bruised out of round. The mechanic took it to his shop to get it back to shape were it met the hose and clamps. All went back together easily and quickly. When we turned it on it sounded excellent. In a few moments all the hydraulic had purged any residual air, it is sounding and moving wonderfully. Seems strong, will put it to use today and will report here if any problems arise. I only run the rpm high when driving, not when using hydraulics. 1500 seems like my usual. There is no doubt, but that this site makes me feel competent to do repairs. You people, and your freely shared wisdom is awe inspiring, in the least. Thank you again and God bless you fine souls.
Glad to hear you got it going smooth! FYI when I did mine the first time there was a rubber disc that had come loose from inside the filter/screen lodged in the intake tube restricting it. Next time you change fluid here is a crude drawing I made for a filter/screen removal wrench. You can cut one out of 3/16" or 1/4" plate.