Changing Hydraulic Fluid

[DirtyDog]

I'm helping MikeDahlager repost some info he had posted in a Yahoo group.

Hello, well it's done and it was one heck of a chore. Drained and flushed the whole system with air. And the top lifted for the first time in three years. Robert the hydraulic fluid is rated for all weather. That is the fluid that John Deere adds at the factory for all there equipment. East coast, West coast and all points in between. They use the same fluid. Ted I found out the hard way about filling the system when the top is up.*** I had a bit of a mess with my 8' non cab over. Learning experiences are always fun.

So this is what I did to drain and flush the system. First off I removed the fitting at the furthest cylinder from the pump, which is the right rear and attached a rubber hose to it. I placed a container below that. I pumped the pump until no more fluid was coming out. I then reattached the fitting temporally. Than I removed the fitting at the pump and placed a shop towel around it to catch any oil. Next I loosed and removed the fitting at the left front and used an air compressor to blow air thru the line. When that was done I reattached the fitting loosely and moved on to the next one. Right front, right rear and last the left rear. I then removed the pump from the camper and
turned it upside down to make sure there was none of the old fluid in the reservoir. With that done I reinstalled the pump, hooked up the main line and filled the system with hydraulic fluid. I had left all the fitting a little loose so as when I was adding fluid I was pumping the system to push any air out. When oil started to leak at all four fittings I stopped and tightened them all down. Topped off the reservoir and jacked up the top. As I said it is one heck of a chore, but well worth the effort. It's been a long day and I'm
bushed! Till next time, Harold


Note: In the '01 Op Manual they say--"Bleeding the system is done by running the
pump for 15 seconds in the down position with the gate valve in the
open (or lowering) position."

***Make sure that the top is in the lowered position before you fill up the reservoir! When I spoke to Brian at Alaskan he told me that it is not uncommon for folks to fill it up when the top is up, and then you can imagine what happens when the top is lowered!

 

[jrfromafar]

I may need to do more than bleed my system. I bled the system and it helped, but only getting a small umph from each pump, 105 to be exact to raise the top. O rings seem ok - nothing is leaking. Any ideas?

 

[Mike S.]

Sounds like the pump is bypassing probably needs new O rings, I have the electric system so I don't know how you fix it but it should be straight forward. One of the other people will know how to take your pump apart. Every time I play with mine its messy though, haven't figured a way to empty 2 quarts of oil with out getting it all over everything. Good luck.

 

[Rusty]

I'm getting ready to purge a system myself and plan on installing a valve at the pump for draining most of the system....taking the handle off the valve for "safety"....you have to think about doing this....Mine has been 46 years without a drain and change.

 

[wyocoyote]

I too am "having trouble getting it up" since having reinstalled my older (late 1980's) electric hydraulic pump by Oildyne in my Alaskan.
Unfortunately (or fortunately depending on how you cut it) I mis-diagnosed the issue. My switch and maybe some other electrical fried. I didn't figure this out until after removing my pump making a hell of a mess (I now know a rounded head chopstick makes the perfect plug for the lines if you are replacing the pump but not doing a complete bleed)
Even more unfortunately I should have tested the pump motor with 12v before taking to my local electric motor repair shop. Comedy of errors to say the least, but it was disassembled before being tested passed through 3 different guys hands and by the end no one knew how to put it back together correctly. Caveat: There are very important spacers (washers) to keep track of when pulling the armature from the electric motor and key ball bearings below the "fingers" in the hydraulic pump section. An important FYI the very same motor and pump with a different part number is Available through Parker. New PN should be Parker Oildyne HRS-519-000-BOR-S mini electric hydraulic pump. old number on mine was Oildyne Intertech model 910631037 If you just need the electric section, they are still used for outboard trim/tilt hydraulic motors and may be found more cheaply through companies like ARCO out of florida.
Okay just wanted to get that potentially valuable to someone needing to replace their electric pump or hydraulic section out there. Brian tells me what Alaskan has to offer now wont likely fit my camper and that these are/were excellent units.
On to my dilemma: I have it all reinstalled. It is of tanatamount importance your pump is primed after removal and replacement. You got a bubble in on my pump there is a the pump its not going to prime itself off the resevoir I found. Bleeding by running the pump with the lever in the down position hasn't seemed to work either much to my chagrin. Priming the pump is a pain, at least the way mine is plumbed because the place to prime the pump is on the bottom. You open it with an Allen wrench. I had to twist the connectors one direction (the L connector needed to face up in the same direction as the priming orifice. Ughh. I have gotten mine where it only gets a small umph much like jrfromafar above. It is still possible the hydraulic pump is at fault but it seems to shoot fluid pretty well now. I have found what may be a fill valve atop the manifold. I'll try and speak with Brian again soon at Alaskan, then post.

 

[wyocoyote]

After talking to Brian at Alaskan sounds like even my in older system air in the lines is very unlikely to be part of my issue. The system is indeed open and self purging. H tells me that even when they build a new one, the top goes up without having to fill the rams. I thought I was dealing with a closed system like hydraulic brakes initially.
He said check valves can be at fault (on those with check valves) and or the up/down valve itself. I'm removing my hydraulic pump again. Aaargh. sure seemed to be pumping well.

 

[Boise]

Got my camper in my shop for spring maintenance and purging the hydraulics.

1.) Problem is that I loosened the up/down valve maybe a little too much and now the pump is not pumping. Perhaps the check valve seal needs replace?

2.) Checking the fluid level I am 3 inches low?


Pardon the interruption, the up/down valve wasn't,t closed all the way--there was a little resistance that "fooled me". So the pump is fine, I may leave well enough alone. The ideal do of a drain valve to purge the system does sound appealing though.

 

[draker3838]

I had a revelation the other day with my hand pump that really helps with the softness on the downstroke. Figured I would share for others with the same problem.

As mentioned in other places, first and foremost, the fluid level must be topped off or else air will get sucked into the pump and the top won't be going anywhere. I had a bad O-ring on my pump which caused the thing to leak with every downstroke and I have a feeling Ill be cleaning it up for a while yet! After replacing the O-ring, I lifted the top without sufficient fluid so midway up, I added more fluid and the stroke was still very soft although I was able to get the top up after pumping 50+ more times. After dropping the top, I began pumping and the result was pretty solid, but still a bit soft. I thought through the pumping mechanism and realized that the "cheater bar" hits the floor before the pump maxes out in the downward stroke. If there is air in the "pumping cylinder," It will remain there until the pump is completely maxed out to purge the air then draw in hydraulic oil on the upstroke. What I did to purge the air is put the lever in the position to lower the camper, then, without the cheater bar, give the pump a few strokes making sure to push it all of the way down and pull all of the way up again. Finally, I switched the knob to the raise position and began pumping. Immediately, the full stroke is solid all of the way to the top.

I replaced all of the O-rings and seals on my pump twice and it resulted in no leaking but weak pumping action. I think having air in the cylinder was my problem and may help others with the same problem. We were looking at replacing the pump entirely, but now it works good as new.

I hope this helps other Alaskan owners out there! Cheers!

 

[David Gendron]

Here is a question while talking about changing the hydraulic fluid!! Is any one that have switch the fluid to synthetic for winter use?
If so what grade/what brand!!

 

[PackRat]

I'm about to replace the whole ram on my LF corner as it has split...the camper came to me with two hose clamps around the end just above where the line is attached and the PO did get a complete ram/tube assembly from Brian prior to my purchase of it. I know about how to support the top while performing the change but I am anticipating some loss of hydraulic fluid during that process.

I found out that the original fluid was "Mil Spec. H-5606-A" which is a mineral oil product and should not be mixed with a fluid like ATF or motor oil. So, in trying to find that I see that NAPA and O'Reilly's hydraulic fluids do not list that Mil Spec and are apparently NOT mineral oils.

A quick call to Alaskan gave me an answer...the lady suggested a "cold weather" hydraulic fluid for things like Caterpillar or Deere systems. The internet lists "H-5606-A" as used for things like landing gear on 1940s era aircraft...as it is a cold temperature adaptable fluid suitable for retractable landing gear.

What are you guys using and where did you get it? As it has to be OK for the O-rings we use and suitable for the pump/ram assemblies in the Alaskans, I suppose that is why a mineral oil is suggested and why we should not be mixing types.

 

[Wandering Sagebrush]

Go to your local airport civilian maint facility. It’s about $40/gallon. I use it as an approved alternative for my boat’s hydraulic steering. It does have a red dye. Bye the way, Teleflex/SeaStar asks about $35/quart.

 

[OSUFlyer]

+1, I also ran the same in my boats hydraulic steering. The red color was great for leak detection.

If you only need a quart for your Alaskans vs a gallon my local airport sold the hydraulic fluid in qt cans for around $7-10 each

 

[Wandering Sagebrush]

+1, I also ran the same in my boats hydraulic steering. The red color was great for leak detection.
If you only need a quart for your Alaskans vs a gallon my local airport sold the hydraulic fluid in qt cans for around $7-10 each

Apologies for a hijack... what boat do you have?

 

[OSUFlyer]

Apologies for a hijack... what boat do you have?

I had a 20’ North River Seahawk with a 115hp Suzuki. It was the little brother to the longer and wider models. Great little boat for running around on the Lower Columbia. Sold it a year ago, but our plan is to be in the market again next year sometime.

 

[Wandering Sagebrush]

I’m running a Suzuki 115 on a CDory 22 Cruiser. Good luck on your boat search.

 

[PackRat]

are those products mineral oil based or petroleum? I'm thinking maybe it has to do with the material the O-rings were made of back in the day or perhaps even now...will a petroleum based fluid break them down.

I did read that while 1940s landing gears used a mineral oil (see the mil spec above) later on a different fluid was used and the two are not compatible...so...if they are not compatible, you would have to drain and flush the whole system, pump included and then be sure your O-rings were petroleum capable.

I have friend looking in the maintenance sheds at a smaller airport that services old planes and a couple WWII birds to see what they have and maybe get me a pint to top off my reservoir after the ram is replaced.

Your thoughts gentlemen?

 

[Wandering Sagebrush]

We used it in the antiques I used to crew. (C119Fs, C117D) The C117 (DC3) made in 1946 is two years older than me, and I’m older than dirt. I believe it’s still flying.

All that history aside, I can’t tell you if it’s mineral oil based.

 

[PackRat]

Hmm...foiled again!
I have had the top in the up position for two weeks now resting on the pins and the pump valve OPEN.
I just went out and cut me a 23 5/8" long broomstick as suggested and then tried to decide if it was to be placed outside on the LF corner of my CO to support the top or....if it was to be placed inside near the LF cylinder resting on the upper bunk frame and supporting the crossbeam that the front rams are bolted to.

Have I lost ya yet?

Anyway, I decided to go with the support on the outside of the camper and proceeded to tighten the valve and raise the top. I got it up enough so that about 1 1/2" of the ram tube was exposed below the pin hole but that seemed to be close to one inch short of the broomstick fitting either on the inside or the outside locations.

I tried raising it again, using the "hard push" action to get the fluid moving but I could not get it up high enough and I saw that it was settling back down onto the pins. I checked the floor below the LF ram where I had found fluid before and had cleaned it up and sure enough...another puddle of maybe a couple ounces or so had collected and was running down the wooden brace the cylinder sits on.

Now I can't get it to raise off the pins at all....hard strokes or gentle...I get the feeling I have lost enough fluid that the pump is EMPTY and I am trying to pump AIR into the system so I stopped and decided to consult the pros here.

I know I need fluid and am trying to find MIL SPEC M-5606-A as the mfger suggested but until I do find some of that stuff I am not going anywhere I guess. However, I think this is where I need to go with this:
1) pour 2-3 ounces of fluid into the pump reservoir and secure. Close the valve
2) with a bunch of rags to collect the fluid I anticipate will be leaking out of the split tube with the two radiator hose clamps on it, start pumping the top UP
3) remove the pin on the LF ram quickly insert the broomstick in the location advised by you guys and begin to let the top back down.
4) once the broomstick is supporting the top, let the valve OPEN all the way so the three remaining rams settle onto the pins
5) unscrew the bolt in the top of the ram and remove
6) push the ram down into the cylinder all the way and close the valve
7) remove the two screws holding each of the "U" clamps on the front of the lower section.
8) stuff a bunch more rags under the cylinder and unscrew the fluid line to that cylinder.
9) remove cylinder with ram down in it
10) install new cylinder/ram assembly and replace line to pump and two "U" clamps
11) attach bolt to hold ram to upper bracket
12) lower top and then refill pump reservoir.
13) check for leaks

Let me know if I am on the right track here....

But.......when I have mounted the replacement cylinder/ram assembly, should I remove the cap on the reservoir and have the valve OPEN? Then once the bolt is tightened to hold it to the upper bracket replace the cap and lower the top? I am partially concerned that right now so much fluid has leaked out I can't even GET the top up unless I add some fluid....so is that "2-3 ounces" too much?

....and yes, I too am older than dirt unfortunately!

 

[PackRat]

If at first you don't succeed...

OK, I couldn't raise the top as air was bleeding out the crack in the bottom of the cylinder I needed to replace. I barely got it up and on the pins last weekend so....how to support it while installing the new cylinder/piston from Alaskan?

Easy-peasy...got my floor jack and a board and gently raised the LF corner until I could install the 22 5/8" broomstick. Then I undid the top bolt and pushed the piston down...hearing bubbling in the pump which confirmed air in that cylinder and in that line. I undid the two "U" brackets and undid the copper line to it and removed it.

I found that a trip to the ACE was needed to get the proper brass fittings as it looks to have been cobbled together at some point in time. Now it is ready for bleeding and fresh fluid and as soon as I secure some mineral oil for it I will finish that task.

Now I have TWO cylinders and pistons that have cracks at the bottom...each is about one inch long. Not sure what to do with them, but I'll hang onto them for now. During the removal of that leaky cylinder I drained out the remaining fluid. The OTHER cylinder that Randy had replaced at the LR location came with the Alaskan and I drained out the fluid in it.

Hmm...they don't mix....I think that tells me that one was mineral oil based and one wasn't...which means bleeding the system out and refilling with MIL SPEC H-5606-A is next...as soon as I find some. I did locate one seller but they had five gallon buckets for something like $200+ dollars! I'm not in THAT much of a rush. AEROSHELL in a one gallon can up in Fairfield is an option also. Maybe my buddy Matt can find some up at the Sonoma Airport today.

 

[PackRat]

Got Brian on the phone up at Alaskan. He says any John Deere compatible hydraulic fluid rated cold weather and about 15 WT will be OK. Grabbed a gallon at NAPA of their best stuff. I bled the line next. Then it was a bit of guesswork...I knew the fluid had run out of the LF cylinder so I checked the level in the reservoir and didn't get but the tip of a screwdriver at the bottom wet....so I eyeballed putting in fluid, then raised the new piston 1/3 of the way and then checked the level again and it was at the bottom again. Repeated twice more then bolted the piston to the top bracket.

Then it took about 40 full strokes to get resistance and then my LF corner supports fell out. I went up some more and dropped the CO sides/front and then tried to lower the top but it was binding at the rear....OK, I checked and sure enough I had moved the truck a bi forward making it not level, I backed up to where it was level and it came down OK.

Enough for today....I will experiment tomorrow to see if I can raise/lower it as it should move smoothly to see if things are OK...no leaks from my new cylinder or fittings so far. Maybe I have got this #1 problem solved!