RK 24 3rd Hydraulic Line purpose

[Iceman Batten]

There are 3 hydraulic lines for the RK24 backhoe. It works properly with only two of them connected. What is the purpose of the 3rd line? The two I have connected are the larger connectors which (on the tractor side) have to be connected together when the backhoe is removed. The 3rd line is slightly smaller, and I would like to know what it is for, since the backhoe works normally with out that line connected.

 

[agjones]

Most often an odd line is for a case drain. Usually smaller than the others. That would be unusual for a backhoe since a case drain is relieves excess pressure in a rotating implement like a wheel motor or auger head.

I attached a page from your bh manual w the hydraulic diagram. It shows a 3rd hose but I'm not sure for what.

My rk55 backhoe only has two.

Can you post a picture?