HydroGear issue

dheisler · #1 09-02-2017, 08:31 PM

Hey guys, I've got a 1863 (with BDU-21L hydrogear) with excessive hydro whine after a tear down to fix a leak. After the tear down/seal replacement, I buttoned the hydro pump back up, filled it 3/4 full and reinstalled it, drained trany fluid from differential, replaced the filter and refilled with Hytran (meets IH specs) which is what I had been using for the last couple of years. With the rear wheels raised, I ran it at medium throttle and in neutral and could immediately hear it whine, full throttle was worse. Shut it down, Loosened the bypass valve and foam type consistency came out...so figured there was air in the system. repeated a few times and it got better to a point where 3/4 throttle and 3/4 speed was ok with no load, but full throttle still produced the whine. Took it for a test drive and forward and reverse are fine on a flat to downhill, but slight incline produces much whine and below normal power. It worked fine prior to the tear down/seal replacement, what I would consider normal whine only during heavy load. The bypass value seems to be working fine. The two checkvalves also seem to be fine. Besides the obvious of what's wrong... how full should I fill the hydro pump before reinstalling?

J-Mech · #2 09-02-2017, 08:37 PM

You don't have to fill the hydro before installing. It fills with the rear end. The system is self bleeding. You have a suction line leak. Find and fix it. Won't be easy, they seldom leak, unless they are low enough too. Either that, or you didn't get enough oil back in it.

dheisler · #3 09-02-2017, 09:00 PM

ok, makes sense. I'm thinking supply line connection down at the filter. I shall get to work and report back. Thanks for the help.

dheisler · #4 09-02-2017, 10:56 PM

Ok, we are back in business. Installed the pump this time with no fluid, just the parts lubricated. I've been through this install process now about three times and the only for sure difference is that this time I did not fill the pump full of fluid, could that have caused my issue? Only fitting that was suspect was tight when I checked it.

Now just have to fix the high pressure line fitting, still must be slightly mis aligned.

J-Mech · #5 09-02-2017, 11:06 PM

Quote:

Originally Posted by dheisler

I've been through this install process now about three times and the only for sure difference is that this time I did not fill the pump full of fluid, could that have caused my issue?

No. Adding fluid to the Hydro did not cause your issue. Not sure how you got it to hold fluid at all..... Oil should have ran out the back output shaft bearing.

Quote:

Originally Posted by dheisler

Only fitting that was suspect was tight when I checked it.

The suction line is the one that runs to the top of the unit. The line nuts aren't the only suspect items. Both the 90 deg fitting at the top, and the fitting at the bottom are o-ring type fittings. Make sure they are tight, and hopefully you installed new o-rings during one of the many times you had it out....

PeterJ · #6 09-03-2017, 09:56 AM

deisler,

Your comment, "...refilled with Hytran (meets IH specs)...", has me wondering what you used.

20 some years ago, I replaced the fluid and filter in a 1512 with "meets IH specs" fluid from the local Fleet Farm store. It allowed the hydro to free wheel down the ditch.

I inquired about it with my local Cub guru and he knew what I did after I told him the symptoms. I changed out the fluid and filter with the real stuff and all was well.

I'm not saying every Hy-Tran equivalent is bad, or that your fluid is causing your problem.

PeterJ