Branon Hydraulic Oil Cooler Problems.

[JRTJH]

I've got a 2012 Branson 2800H tractor. The first winter I owned it, the temp was somewhere around 15F and when I started it, the Oil Cooler started spewing hydraulic fluid from the input (just below the fitting). I built a bypass hose, drove it onto my trailer, towed it to the dealership and they replaced the Oil Cooler with what I was told is the "improved part number". It worked well the rest of that year. I changed hydraulic fluid at the end of spring. No problems until it got cold. Sometime in mid January, about 15F again, the tractor started leaking at the rubber seal on the hydrostatic drive filter. I changed out the filter and all was good until today. I started the tractor, it was 18F, let it warm up about 2 or 3 minutes, lifted the bucket and pressed on the forward pedal. The Oil Cooler started spewing hydraulic fluid at the same location as the first cooler. I called the dealer, he is overnighting a new cooler, but I can't help but think that there's something causing this to happen. I'd sure like to find the cause before the warranty expires, but with the little knowledge I have of hydraulics, I'm out of ideas.

So far, I have ruled out the fluid. I use NAPA 85-475 fluid (per dealer's recommendations), the filters are new (changed the fluid and filters in late August), there is no corrosion on the Oil Cooler or fittings. and the fluid, to the best of my knowledge is clear (but thick and cold) with no water that I can find.

I've got an idea (work around) that I think will work for extreme cold weather operation: Bypass the Oil Cooler and eliminate the problem. My concern is that if I do, will I be eliminating the "weakest link" and moving the potential for damage to a more expensive component? Or ????

Any thoughts on how to stop this from happening while I'm still in warranty would be appreciated...

Thanks

John

 

[bigdeano]

I think your fluid may be too thick for extreme cold. I found this on another forum.

I run a NAPA Auto parts store and universal tractor hydraulic fluid that NAPA sells meets Case/IH spec #JIC 143-145/MS1204-1206(Hy-Trans). Part # 85-475, this is for warmer climates. Part # 85-401(1 gallon) and 85-405 (5 gallon) are the premium heavy duty tractor hyraulic fluid that is for year round use (meets same specs).

Maybe you could put a heater on the reservoir to thin the oil some. I think you're getting too much back pressure in the filter and cooler from the thick oil. Of course I could be totally wrong too.

 

[JRTJH]

Thanks bigdeano,

I also think the 85 475 fluid gets too thick when cold. It is like "honey" or "syrup" and is much MUCH thicker than it is during the summer. I'm sure the back pressure is probably what's causing the Oil Cooler to rupture. Funny that it's been in the same place both times (unless the dealer's service tech twisted the input fitting and weakened the aluminum tank ????). My concern is "if" I build a bypass hose and just disconnect the Oil Cooler (during the winter when plowing snow) am I changing one weak link and creating another? As frustrating as it is, I'd rather "break" the Oil Cooler and save the HST (if there's an issue with damage there if I bypass the Cooler..... Anyone have any thoughts?

 

[bigdeano]

Hydraulic fluid should never be that thick or you run the risk of cavitation and pump damage. You may not hear it cavitating because of engine noise. I would say either change to a thinner fluid or use a heater, which may not be possible.

 

[oldnslo]

JRTJH,
I had the same problem of blowing the HST filter seal on my 2400H last year. Dealer told me they had some faulty oil coolers that was restricting the flow to much causing the excessive back pressure. On mine the new "improved" cooler has no aluminum cooling fins which to me limits the effectiveness of the cooler.

Dealer also told me that there is a line inside the tranny than can rupture. I sure would like to see an accurate hydraulic schematic for these 00 series tractors. Any good HST should have a full flow relief valve that would limit the charge pressure and protect all of the components from failure.

 

[JRTJH]

Thanks for the info, oldnslo. When we were talking yesterday, my dealer also told me that the 2400/2800 HST oil coolers had a defective run of parts and that last time mine failed (in 2012), he "thought" they installed the new type. Mine looks just like the one that was originally on the tractor, so apparently, if the newer ones don't have aluminum fins, then I've still got the "old type". So that may be the problem I'm facing now (along with the "too thick oil"). He ordered a replacement oil cooler, should have been here today, but with the snow we've had, I suppose things are slowed down all over the northeast. FEDEX and UPS both have disclaimers on their websites indicating the storm is causing delays. Hopefully I'll get it tomorrow. I did have a bypass hose built today and installed it so I can get some of this white stuff moved, but I'm not really sure I like not having the cooler in the line. Even in 20F weather, working the tractor hard, the oil gets hot. I don't know if it's "too hot" or really just how much help the oil cooler gives to the HST. I did pick up some NAPA 85 405 hydraulic fluid today and replaced the 85 475 that I had been using, so tomorrow I'll see if it's any "thinner" than the old stuff. Hopefully it will make a difference. I also put a spotlight/heatlamp under the tractor (it's in the pole barn) so that may help keep things above freezing at least.

As for a "hose inside the transmission", the parts breakdown on the Branson website doesn't show any tubes inside the HST, so is he possibly talking about the filter hose that comes out of the HST and into the filter block? or the supply hose that goes into the trans/rear end on the right side above the hydraulic filter (the hose with the wire mesh screen) ???

 

[oldnslo]

On an HST tranny I wouldn't get to concerned until the oil temp reaches 170 - 180F. Better if they stay in the 100 - 130F range though.

More plumbing but another option taht I have considered is to install a by-pass valve on the cooler. Install something like a 20 PSI check that allows the oil to by-pass the cooler when inlet preesure is 20 PSI higher than the outlet pressure. This is common on mobile equipment for cold weather start-ups.

Parts breakdown on the Branson website that I can view is pretty vague. It doesn't show any lines to or from the HST that I can see nor does it show the charge pump which I presume is built into the main HST pump. I suspect there is a line that goes from the charge pump to the filter assembly that is not shown on the parts break down.

 

[JRTJH]

I talked to the dealer again today about the oil cooler. Seems that the aluminum one with fins that split this week "IS" the new "improved one". Apparently there was a second "improved cooler" which is the one you have. When I described it to him, he called the tech support section in GA and they explained to him that there were still problems with the modified aluminum cooler and they started using the copper one without fins for problematic tractors (whatever that means). The dealer explained that there are a number of tractors "in the south" with the copper cooler and there have been no problems with overheating. ???? He ordered the copper cooler for my tractor and said that if it fails, we'll have one built locally. So, I'm leaving it in his hands for now, but hopefully there won't be any issues with this plan. I did order a Kat's 200 watt magnetic cooler, I think it will be small enough to fit on the flat bottom of one of the axle castings. If not, I'll figure out some place to stick it when I need to get an early start on cold mornings.

As for the parts breakdown on the Branson site, it is confusing, but there are a couple of diagrams of the HST hydraulic lines. They aren't listed with the HST, but are separate with their own diagrams.