Oil & Fuel have a curious oil leak on a new holland 1630 hydrostatic

   / have a curious oil leak on a new holland 1630 hydrostatic #1  


New member
Dec 16, 2011
boomer 1630
I have a curious oil leak on a new holland 1630 hydrostatic 1999 vintage. The engine oil is dark needing a change but is full and not requiring additional oil. the leak appeared to be hydraulic as it was coming from the hydrostatic case. The leak appeared to be coming from where the hydro pipe coming from the HST filter is going into the case on the left side of tractor. there is the pipe , an O ring, and the spring bracket for the brake pedal which holds the pipe into the HST pump. Now when I loosened the bracket holding in the pipe - I got a rush of fluid out of the hole the pipe goes through - about 1.3-1.5 gallons - all dark in color. Thought it might be that the HST filter was bad. when I removed the HST filter, the fluid there was crystal clear. When I finally pulled out the pipe - it too had clear fluid in it. So I opened the drain plug a little further back (the one to drain hydro fluid) - and got a flow of clear hydro fluid. So even after draining the hydro fluid - when I poked my finger into the HST Hydro pipe hole - there was more of the darkish fluid. So now the mystery - if the hydro drain is logically the lowest point in the hydro system - where is this fluid coming from? If all the hydro fluid is clear - why is the fluid in the HST case dark? Is there supposed to be fluid in that case?? Any ideas before I'm left with the only alternative is taking it to a new holland dealer (trhere are becoming fewer and fewer of them) for them to open up?
   / have a curious oil leak on a new holland 1630 hydrostatic #2  
I realize this is an old post, but in case you are still trying to figure it out, on my 1520 there is drain vent in the bottom of the hydrostat case (It is a drain plug with a hole that has a cotter key in it) and it can get plugged so that any liquid that finds it way in there will not drain. If you have a hydrostat line or pump seal leak inside the case, that is where the oil will go. If it can't drain out the bottom drain, it will collect until the level gets high enough to overflow through one of the case perforations where linkage and hyd lines pass through. I am not where I can look at my tractor to verify if this fits your description, but it will be dirty and dusty inside the hydro case because of the above mentioned case perferations and any clean hydrostat oil that gets in there will come out dirty.
   / have a curious oil leak on a new holland 1630 hydrostatic
  • Thread Starter
Well, an update for you. Took it to New Holland and they did a diagnosis - not pretty. Seems there is an opening on the top of the hydrostatic case and mice have a habit of finding it and the case is a perfect place to live if you do not use the tractor daily. The material they bring in can get would around the shaft and ruin the Hydrostatic pump seals - thus causing the leak. The material also plugged the weep hole - thus the build up of oil. When I poked into the hole, it cleared the material and drained the case. NH dealer want $4k to split the tractor and examine the hydro pump - its 1K for a seal kit to rebuild teh pump if the shaft is not scored or ruined. Its 5K for a new pump. Needless to say, I'll live with the minor leaking till old age and I buy a new tractor. Oh well
   / have a curious oil leak on a new holland 1630 hydrostatic #4  
Can you snap a few photos of the site.
   / have a curious oil leak on a new holland 1630 hydrostatic
  • Thread Starter
Can you snap a few photos of the site.

Not sure what Pics you want -
I have pics of the side of the hydrostatic case where the oil tube goes in. As I said, it is held in by a bracket that also holds the springs for the brake pedal. The tube has an O ring and mates into the pump. It comes off the Hydrostatic pump filter ((left side facing forward) and is common to all the early boomers (1530/1630/1730). circa 1996-1999. The opening I mentioned is only visable if you rremove the side covers, steering unit and some other stuff, so I have to rely on what the NH guys told me. The hole at the bottom of the case is small 1/8-1/4 inch size with what looks like a cotter pin push in from the inside and split slightly. When I pushed a probe (dental tool) up inside, it freed the gunk and as it was flowing out, there were tendrils of cotton like fibers, 6-10 inches long I could grasp and pull.
The case itself is between the clutch (yes, even though it is a hydrostatic trans, there is a clutch (only use I have for it is the PTO) - so the sequence is engine - clutch - hydropump (front) case - hydro pump (back) and hydro transmission case - rear case (differential), PTO and 3point hitch

Lot to get at if it goes wrong

Hope that helps - have pics of all but the hydro case top as I have not decided to open her up yet. Have to weigh the leak vice 1-5K to fix myself (plus time) or an added 4-5 K for NH to do it
   / have a curious oil leak on a new holland 1630 hydrostatic #6  
It's 2024 and I have the same problem (exactly) with my 1630.
Im going to have to split it in half.
Im not looking forward to doing this.
Any advice would be much appreciated.
   / have a curious oil leak on a new holland 1630 hydrostatic #7  
My experience with my 1995 1520 hydrostat (in 2014 at 2650 hours) was that after I started noticing a hyd oil leak from under the tractor (from the drain hole with the cotter key), the leak went from tolerable to a an intolerable steady drip (while operating) within about 50 hours. I have made sure the drain hole has stayed clear as part of annual maintenance since new. I split the tractor myself and took the hydrostat unit to a hydraulic shop that charged me $1,100 to rebuild it with a seal kit and new input shaft. I was told that my hydrostat unit looked good (except for the seal) and they typically recommend replacing the input shaft (if customers intend to keep the tractor for awhile) due to spline wear. Splitting the tractor was not hard as I have an overhead beam with a couple chain hoists in my garage along with using a couple floor jacks. I also had previous practice because I had split it 2 years prior to replace a clutch throwout bearing. My only disappointment with the repair is that the hydrostat is now more jerky (does not return to neutral and stop as smoothly as before) especially when stopping while backing up. I replaced the dampener (under the right foot floorboard) on the hydrostat linkage which helped some. It is now 10 years later I am at 3500 hours and no leaking.