3505 Mahindra loader

[TexasBill]

I just had installed a bush hog loader. Works great. My dealer says that when the loader is removed the pressure hose and the return hose have to be connected together or the pump will blow up. The hyd. valve on the loader is of open center type. Question? Was not the opening on the pump plugged before the loader was installed. And was not the return system plugged. So what has changed? TB

 

[jonrjen]

Hey Bill,
I don't have a Mahindra as of yet, but I do have another small tractor that does have to have the two hoses connected when the bucket is off of the tractor. It seems some of the off shore manufactures use a closed loop hydro system which feeds the fluid in a constant flow. This powers anything hyd., Power steering, FEL to three point. If the loop is not connected at some point the pressue will build up to the point in which the pump cannot force any additional pressure and result in at best blow a gasket to release excess pressure.

 

[Varmintmist]

I know the hydraulics for the hoe on a 950 Deere have to be connected together when you pull it, not just a Mahindra thing. I assume that there was a bypass before or the plumbing was changed somewhere to get hyd to the loader. If the circut is there, there needs to be a return for the pressure.

 

[TexasBill]

Thanks guys, for your input. I guess I was wondering if it all worked before the loader was installed why it would not work when it was removed. I would think it would have to have a relief system some where. The hyd. pump runs the loader and the three point lift. Powder steering has its own pump. Anyway is no trouble to hook the hose together I just wanted to know how it worked. I have not been able to buy a repair manual for this tractor. Do have operators manual and can get a parts manual. TB

 

[DavesTractor]

Probably the pressure comes from your pump through your valve and then on to your three-point. When you disconnect the loader and disconnect the hose going from the pump to the loader valve, you have effectively plugged that hose as the quick connect has a valve in it that closes when apart from it's mate. Now if you start the tractor, it takes about a nano second for the pressure to build up in the short hose and it either breaks the hose (unlikely) or breaks the pump (likely). Pumps like these do not have a pressure relief, that is further on in the system.

Your dealer was wise in explaining this to you and he is surely correct. You also wonder why it would work before the loader was installed. It worked because the line from the pump was not interupted by a closed valve (when a hose is diconnected at a QC) and just went on to the three-point. The loader valve isn't the issue, it's the QC's. Now on most factory loader installations, pressure is taken from a location downstream from a pressure relief, so this catastrophic pump failure can't happen.

Your installation is typical of an aftermarket install and is just fine.