1990 520H Hydro Change Procedure

[echoffmann 2]

Sorry if this has been covered, if so I'll delete my post. I'm changing the hydro fluid and filter on my 520H. Is there a special procedure to refill the system, or bleed out the air?

[rmaynard 15,609]

I found that once I got most of the old oil out, refilling very slowly through the dip stick tube while letting air out of the seat bracket bolt hole on top of the transaxle was the method that worked best for me. I also ran it, then checked and added oil as necessary. Be sure to use the correct hydro filter.

[squonk 41,345]

What bob said. Use a Napa 1410 filter.

[echoffmann 2]

Thanks for the tips! I didn't figure there was much to it, just didn't want to think I'm doing it a favor, and then overlook something and ruin my dependable 520H. 

[Vixmith 25]

When re-filling through the dipstick tube I had much trouble because the oil was trying to go down and the air inside the empty transmission was trying to escape through the same dipstick tube.  Nothing would move.  My solution:  Get a length of 1/4" tygon tubing and insert it through a 6" plastic funnel letting the end hang down to a point equal to the length of the "full" mark on the dipstick.  You will want to measure from where the funnel rests on the dipstick tube.  Duct tape it there so it will not move when filling transmission.

When the new oil goes down the dipstick tube, the air escapes up the tygon tubing until the oil level inside the transmission reaches the bottom of the tygon tubing, ie., the full mark on the dipstick.  Then it will air lock again and stop letting oil go down the funnel.  Makes no messes because I left the end above the funnel long enough but not a siphon.  Works well.  Definitely speeds up oil going into the transmission.  May have to take funnel/tube arrangement out and run the transmission a couple of times till you get the complete 5 Qt's into the transmission.  NOTE:  recommend you measure how much oil you drain so you will know how much to put back in.

Good Luck.   I will try to get some pic's of this arrangement on here later this evening.

 

Really like my 520H ! 

[JAinVA 4,623]

 I found a funnel at wally world that solves the problem of air needing to escape when putting oil down a long narrow  tube like the fill tube on both the manual and hydros.This funnel has a rib down the length of the thin section so that when inserted in the fill tube it allows air to escape.If you have a funnel that fits then something the size of a toothpick between the funnel and fill tube will allow easy filling.Just don't let the tooth pick fall into the trans.JAinVA

[scoob8000 29]

I read a great tip posted on another forum.  Leave your new filter loose a couple of threads while you pour your oil in.  You'll get to a point though where you start spilling fluid from the filter and will have to tighten it up.  But from that point you only need a couple more pints.

[doc724 925]

Removing one of the bolts that holds the u-bracket (which supports the rear fender) works very well.  You have to have small hands and a ratcheting box wrench to get in and remove one of them however.

[cheesegrader 433]

I let the system vent out the filter.  Once hydro fluid reaches that level, I tighten the filter, and have less than a quart left to dribble in the hard way.

Also, make sure the fluid is WARM.  If you store your fluid in a frozen barn, it will belch and spit like mad whan you add it down a narrow tube.

Edited April 10, 2016 by cheesegrader

[DougC 2,641]

 I set my oil in the sun for about an hour so it gets really warm and flows much easier. 

[cleat 6,357]

I used to have an old microwave in the garage to heat oil.

 

Likely not safe but it worked.

 

I only got rid of it because of space and now have more room again so will likely pick one up at a yard sale or classified cheap to replace it.

 

Also handy for rewarming that coffee you took to the shop then got preoccupied and forgot about.

[DougC 2,641]

Remind me not to buy a used microwave from cleat.....................

[Vixmith 25]

Hello fellow Red Square folks,

 

posting the pix I mentioned in comment #5 above in this thread for my funnel and tube tool to fill the 520H's transmission:

#1 shows funnel in fill tube to note how far down it goes into the tube.

#2 shows measuring the tube alongside the dipstick to see how far to let it hang down the fill tube below the bottom of the funnel.

#3 shows my sloppy duct taping of the tygon air vent tube in the top of the funnel.  Avoiding any possibility of a siphon.

 

Hope this is of some benefit to others..

 

Thanx,

VGS

[cleat 6,357]

Your pictures show the engine dipstick and tube.

Same procedure should work for the rear end though.

[Vixmith 25]

10 minutes ago, cleat said:

Your pictures show the engine dipstick and tube.

Same procedure should work for the rear end though.

Hello fellow Red Square folks,

 

posting the pix I mentioned in comment #5 above in this thread for my funnel and tube tool to fill the 520H's transmission:

#1 shows funnel in fill tube to note how far down it goes into the tube.

#2 shows measuring the tube alongside the dipstick to see how far to let it hang down the fill tube below the bottom of the funnel.

#3 shows my sloppy duct taping of the tygon air vent tube in the top of the funnel.  Avoiding any possibility of a siphon.

 

Hope this is of some benefit to others..

 

Thanx,

VGS

 

Cleat,

 

You are absolutely right.  Had so much trouble getting the Hi-Res pix from my cell phone re-sized for downloading to RS that I lost focus on what they were actually showing....early 0n-set Alzheimiers'  ????  {:>))  (RE-sizing the .jpg file.)

In fact I have never had to use this method for adding engine oil.  It flows easily into the larger engine fill tube with no air-locking.  Only used it for the transmission oil fill. 

When I bought this tractor last spring, I had to add 2 qts to transmission just to get it to load onto trailer.  Figger the shop guy had changed the oil and had so much trouble getting new oil in that he just said "Close enough!" and stopped.  Added another quart when I got it home.  That's when I figgered out this vented funnel.  No leaks since topping off.  Runs great.

Thanx for the correction.  Apologies to everybody my erroneous pix confused.

~ VGS 

[echoffmann 2]

Awesome tips guys! I've usually lucked out with other forum topics (STV stuff) but this is great! I'm going to try rmaynard's trick with the bolt removal. I have the fender off already so much easier access to it from the top.

 

Thanks to all who replied.

[cleat 6,357]

And when you put the bolt back in, put just a little liquid thread sealant on it being careful not to let any get on the end of the bolt where it can get into the transmission.

 

I was putting them in dry or with never seize and I would always get a few drips under the rear end. Since using sealant (liquid teflon) no more drips.

 

I would not recommend tape as a piece could fall into the transmission.

 

Also, before removing this bolt, be sure to clean the entire area real well, you would hate for any dirt to fall into the transmission.

[Vixmith 25]

Cleat, et. al.,

You raise an extremely good point about Teflon tape.  As a maintenance engineer and instructor of college level hydraulics and pneumatics, I have had some experience with hydraulic stuff.  Have some cutaways and dis-assembled parts that failed.  Have used them for examples.

One was a hydraulic pump that had been destroyed by Teflon tape.  When mechanics had done some piping, they wrapped the male pipe ends with Teflon tape but started about 1/4" before the end of the fitting / pipe.  This resulted in Teflon tape dropping over the end of the male pipe thread.  It subsequently found its way to the hydraulic pump and gathered in the clearances, creating destructive wear. The pump had to be replaced. 

Correction was as Cleat recommends, "Hold the sealant back 1 1/2 threads from the end" in this case the end of the bolt.  I would expect Teflon paste to do the same thing as tape inside pumps and valves.  The other problem with venting via the bolt is that next time you remove it, there is always the opportunity for whatever sealant used the previous time can fall from the bolt into the transmission.

Just another reason that I prefer venting air back up through the fill tube with my small tygon tubing in the funnel.  Less chance of foreign crap getting into the transmission, which is a Hydraulic machine, or of leaks cropping up in hard-to-reach places - which forces the need for the sealant in the first place.

 

Thanx to echoffmann for opening this discussion thread.  Always happy to learn and to share lessons learned.

[Phatboy 565]

Maybe im mistaken but being as the transaxel housing is used as the resovoir ,,doesnt the oil go from the resovoir to the filter then to the pump ? Im pretty sure it does,, so if any paste resido drops in transaxel houseing or tape for that matter will be trapped in the filter prior to being introduced to the pump...correct ?

[WNYPCRepair 1,921]

5 minutes ago, Phatboy said:

Maybe im mistaken but being as the transaxel housing is used as the resovoir ,,doesnt the oil go from the resovoir to the filter then to the pump ? Im pretty sure it does,, so if any paste resido drops in transaxel houseing or tape for that matter will be trapped in the filter prior to being introduced to the pump...correct ?

 

 

I believe the filter is on the return line, after it has gone through the pump, but I could be wrong

 

[JAinVA 4,623]

If the filter is on the pressure side them it's different than any hydraulic sytem I've ever seen.

[Phatboy 565]

If it sucks from the resovoir thats not the presure side its not presurized until after it goes threw the charge pump right ? At least i think that is how it goes ,, not sure maybe some of our experts can clear this up as i am not totally sure exact path,,,but i always thought it went from tank to filter then pressurized once it enters the pump.. Cause there isnt anything to pressurize the trans axel,, if there were pressure in there it would blow the dip stick out,,so jainVA i think you are right for sure i think lol.. 

Edited April 15, 2016 by Phatboy

[tbarnhart 240]

Pretty sure WNYPCRepair has it right. There should be a suction mesh strainer in the sump. From there, it sucked up by the charge pump and used to prime the piston pump and motor. There is an auxillary port to supply pressure to the lift valve, and the oil then returns to the sump through the filter. A few hydraulic systems have filters on the suction side, but not many. Pumps don't like to draw oil through a restrictive filter, and can be damaged by poor flow.

[cleat 6,357]

My diesel tractor has it's filter on the suction side.

 

Obviously at this position it is a fairly large micron filter.

 

As for the Wheel Horse 1100, You can follow the path from the charge pump to the control valve back to the filter and then back to the rear end housing.

This is only for the hydraulic lift, the filter does nothing at all for the motion control.

 

[JAinVA 4,623]

 

           The filter should not see the full pressure of the pressure side .Is that correct?I cant imagine any canister filter not exploding with it seeing the full pressure of most hydraulic sytems.My log splitter has a filter but it never sees full hydraulic pressure.It only filters the return oil.Here is a picture of the funnel that came from Wal-MartThe black line highlights one of the four raised ribs that allows air to escape.No bolt removal or extra tubing is needed to fill any WH transaxle.JAinVA 

Edited April 15, 2016 by JAinVA