Hi Folks, I have an ASV PT100 Forestry track steer that has blown out it's hydraulic heat exchanger (the big radiator behind the engine). I can't see any reason for this, as far as I can tell, any fluid that flows through there goes right back to the tank. In other words, it's on the low pressure side and there's nothing between the cooler and the tank. I had assumed that a component downstream of the cooler (check valve, or what have you) had failed, and allowed the low pressure side to build pressure until the cooler broke. But, from what I can tell, there is nothing downstream of the cooler, so that theory is probably no good. Can anyone help? Why would the cooler burst if there is nothing between the cooler and the tank? Thanks y'all!
Have you contacted ASv for a hydraulic schematic? I have attached the RC100 schematic which should be similar.
If you get a big enough air bubble going through the high pressure system, it can expand with enough force to blow a hose off or rupture a light oil cooler even if there's no valves in the line to the tank. That's my story anyway...
Delmer makes a great point but I have also seen coolers fracture near their mount points from stresses... how about a pic of where/how it blew apart when you get it removed. Another thing to check would be the pressure relief on the tank side of the system.
Thanks f311fr1 for the schematic! I was working off this one: http://trackloaderparts.com/pdf/755...ice_repair_manual_7055_sn_all_english_all.pdf Not exactly helpful, but it shows more or less the same info,as far as the coolergoes. On your schematic, there's one circuit that has an 80psi check valve for the filter bypass, and mine shoes the same. But that's the only thing that I can see that's between the system and the cooler. I'll contact ASV on Monday and see if I can get a real diagram. I'll have the thing in the shop on Tuesday and get a better look at what happened. The guy also said the gasket on the filter blew out. Which filter, I don't know. Gonna find out! Thanks for the pointers guys!I'll post up more when I get eyes on this thing.
Hydraulic return filter. On the RC 100 there is a tank vent run from the hydraulic fill neck under the hood/behind the cab. Mine has an inline filter that the other end vents to the belly pan. Check ypur machine for same and replace the inline filter as it could be pluged and the tank is no longer vented.
Good suggestions! I have not found the smoking gun yet. I removed the cooler and did some troubleshooting. I capped the return line going back through the aux filter and fed some hydraulic fluid into the return line going to the bottom of the cooler. The point of this was to confirm operation of that 80 psi cooler bypass check valve. It opens and drains fluid into the tank at about 65 - 70 psi. I know it's going into the tank because I drained the tank, and saw my new fluid coming out the drain during my test. So, the check valve is working. On to the vent filter. Why there is a filter in the vent line, I don't know. But, I reconnected the lines at the aux filter, and capped the lower 2 cooler lines, and put shop air into the top return line. The tank is venting fine, it won't even hold 5 psi. I double checked by blowing on the vent line before that goofy filter, and she's free flowing. So I am completely baffled as to why that circuit would build enough pressure to blow the gasket on the aux filter and blow a hole in the cooler.
Look at page 3-1 of your service manual. They show a 0 psi check valve in the lower port of the hydraulic cooler. Have you checked this valve for proper smooth operation. If it were to stick closed it would overpressure the cooler.
Is the cooler aluminum? I have seen many crack from vibration. The repair shop I use won’t even try try to fix aluminum coolers,they say buy new
That 0-3 psi valve works witt the 15psi valve to create the bypass circuit for that side. It does the same thing as the 80 psi valve does, unless I’m reading the thing wrong. I installed another 65 psi relief in the aux circuit to do 2 things: tell when the surge is happening, and not hurt the cooler. It looks a little goofy, but at 65 psi, that crack valve will open and dump oil overboard. Until I figure out WTH is happening, I need to protect the cooler. The old cooler was aluminum and the new one is too.
I put 'er all together, and gave it back to the customer. All seems ok. That thing is going back into service next week. I'll post up when I find out how it's doing.