BH77

[morfman]

I have a brand new B2650 with a BH77 backhoe. I've noticed that the boom cylinder and the dipperstick cylinder get very hot to the touch after about 20-30 minutes of use. When they get this hot the backhoe seems to lose a bit of its power. I sent it back to the dealer to see if there were any restrictions in the lines or any other problems. They claim they checked the pressure and temperatures and everything is fine. The dealer claims that the fluid may heat up to 120 to 140 degrees above the ambient temperature. In other words, if it's 100 degrees outside than the fluid could be around 240 degrees. Any expert opinions out there?

 

[Grandad4]

I'm no hydraulics expert, but it shouldn't get that hot with a half hour workout. Something is not right. When the hydraulics are working hard the fluid does get hot to the touch but not scalding hot. If you're digging and waving the bucket around like a wild man for 30 minutes (would love a video of that!), sure, things would get hot, but I wouldn't think working your BH cylinders at anything like an ordinary pace should raise them up to such a high temperature. I have seen the fluid get plenty warm with my BH after hours of continuous use, but never so hot you couldn't touch the cylinders or the lines with your hand.

As a point of reference, the MSDS for Kubota SUDT-2 indicates it has a flash point of 262 Deg. F. Don't think Kubota would design equipment to normally run anywhere near that.

 

[sandyc]

My bh used to get hot. Remember that the fluid from the hst is also used in the bh. You have a tranny cooler that is positioned in front of the condenser and rad so make sure that the screens are clean of debris and you should be OK. Sounds pretty normal.
When I was running my bh I just used enough rpms to get the job done. Digging sand required less power than digging stumps for example.