Help with low hydraulic power

[Chris Australia]

Kohler 25hp petrol with single hydraulic pump checked by shop with 3000 psi from pump
Machine still has fast track speed and loader functions
Symptoms
Low push power struggles up slops and on flat sand
Low lift power
Boom drops down fast with heap load
Engine doesn’t struggle or stall under high demands
Machine comes to a stop if you use loader function while driving
Can not break traction with both tracks but you can with one at a time
Seems to me like it has a internal leak bleeding off pressure somewhere ?
Has a Parker motor for each track
It has a hi and low speed switch that works for track speed
It also has a control valve that apparently takes power away from controls to give to auxiliary attachments which has me curious
Control valve was removed and new o rings fitted by shop
Spent nilly $2000 at shop and not fixed
Any ideas thanks

 

[Chris Australia]

Boxer brute 427 stand on mini loader

 

[Chris Australia]

Machine has no leaks and 1 new drive motor because of wear around shaft seal
Boom drops quickly with a full bucket of dirt

 

[ddbackhoe]

From what I can see here, did anyone check the creep valve (manifold) might have some junk in it or a bad 2 way valve or the high/low switch (page 3-24). I dont see the interconnect for the high/low switch but reading the owners manual, dont really understand why they incorporated one. I’d probably leave it in high and use the creep valve.

https://www.multitrack.com.au/wp-content/uploads/2014/03/Boxer-TRX-Speci-Sheet.pdf#page23

page 5-11

https://midtnequipment.com/content/boxer-parts-manuals/Boxer-427-Boxer-427W.pdf

page 13, item18

https://www.mylesgroupcompanies.com/moog_pdfs/Moog%20introtocartvalves%202008.pdf

 

[Chris Australia]

From what I can see here, did anyone check the creep valve (manifold) might have some junk in it or a bad 2 way valve or the high/low switch (page 3-24). I dont see the interconnect for the high/low switch but reading the owners manual, dont really understand why they incorporated one. I’d probably leave it in high and use the creep valve.

https://www.multitrack.com.au/wp-content/uploads/2014/03/Boxer-TRX-Speci-Sheet.pdf#page23

page 5-11

https://midtnequipment.com/content/boxer-parts-manuals/Boxer-427-Boxer-427W.pdf

page 13, item18

https://www.mylesgroupcompanies.com/moog_pdfs/Moog%20introtocartvalves%202008.pdf

Thank you for that info .

 

[ddbackhoe]

Thank you for that info .

Hope it helps

 

[Chris Australia]

Hope it helps

Gday backhoe .. do you see a relief valve on the diagram ? What are counter balance valves it has them on each drive motor ?

 

[oldnslo]

Counterbalance valve are in the motor to prevent run away when going down hill. They would or should not have any effect on the loader.

Since it appears there is a significant leak flow path I would start by getting an infrared heat gun and from cold start monitor temperatures on the pressure line and the main control valve since the leak has to be in a component that is common to all the circuits. The leak path will create heat and should show up on the infrared pointing you towards the source of the problem.

 

[ddbackhoe]

Gday backhoe .. do you see a relief valve on the diagram ? What are counter balance valves it has them on each drive motor ?

I dont think its as simple as resetting a relief valve. The manifold valve (creep) controls the hydraulic flow (page 34) to wheels, loader and aux circuits. A tiny bit of trash caught up in there would certainly goof things up. I would pay special attention to the flow control cartridge.

 

[Torvy]

Just reading this to learn more, but good luck. The lads and lassies here have a lot of knowledge.

More importantly, welcome to TBN from Texas. We'll assume given your name you are from Down Under. We have many members from the land of OZ.