Main Pump Bad? Diagnosis - Kobelco SK35SR

[barros57]

Make: Kobelco SK35SR. SN PX08-06693 (made around the year 2000?)
One output of the main piston pump seems to be weak (not enough power to skid one track as well as the other functions that run off that "A" side of the pump). I swapped the lines at the pump output and the weak track side changed.. leading me to believe the pump is not putting out proper pressure at one of the "A" or "B" outputs. ( have a hyd. pressure test kit on order)
I took the pump out and disassembled..
Pump is a Uchida Hydraulics
Model: AP2D18LV1RS7-936-0

The brass "plate" looks a little suspect to me... You can feel some slight grooves. Otherwise the pistons/slipper look ok to me...
(I have very little experience with hyd pumps)
Do you think that plate is my issue? Anything else I should investigate or replace? Any pointers/suggestions appreciated!

 

[barros57]

 

[barros57]

Is the wear and discoloring here normal?

 

[Universal Parts]

You need to disassemble the plunger pump and carefully check the key parts inside the plunger pump, including the plunger pump rotor, swash plate, oil distribution plate, return plate, ball joint, and spindle wear to ensure that the proportions meet the standards of new parts. My previous Swedish customer also encountered the problem of low hydraulic pressure. After investigation, it was found that the inner and outer rotor disc oil seals were damaged. His sealing strip was very small. I will attach the picture below and circle it in red. However, his plunger pump model is AP2D25LV3RS7. I hope this information is helpful to you.

 

[Universal Parts]

1

 

[LACHAU]

Hope to be helpful to you.

https://www.mediafire.com/file/mbta1mve0o02m0r/SK35SR-1+Main+Pump+Maintenance+Value.pdf/file

 

[barros57]

I have found a few suppliers on alibaba that make replacement kits that include all the main wear items. I think I may give this a shot.

 

[Universal Parts]

I have found a few suppliers on alibaba that make replacement kits that include all the main wear items. I think I may give this a shot.
View attachment 347440

There is still one part missing, the swing assembly

 

[barros57]

There is still one part missing, the swing assembly

Do you think that part is damaged? I don't know what to think about the discoloration.
Everything seems to be in good shape except for the slight wear marks from the 3X plungers...

 

[Universal Parts]

I can't tell from the picture. First check your oil outlet to see if the flow is normal, or if there is only oil flowing out but no force. The price of the 7 parts in the picture above will not exceed 300 USD. Pay attention to discuss with the supplier you contacted.

 

[Lydia Chan]

You can contact my email [email protected], +8618620466907 Whatsapp. We have pump and also parts

 

[barros57]

Parts arrived today from alibaba - about $250 USD shipped. All appear to be good quality hopefully they work as well as the original.

 

[Universal Parts]

Parts arrived today from alibaba - about $250 USD shipped. All appear to be good quality hopefully they work as well as the original.
View attachment 347991

Your shipping fee is very expensive. I have sent several packages weighing about 1-2 kg to the United States. The starting price is 28.5 USD/1 kg. An additional 8 USD is charged for each kg over 1 kg. An additional 4.5 USD is charged for remote areas according to the zip code. This is the shipping fee calculation formula. FedEx delivery is efficient in 8-10 days.

 

[barros57]

Your shipping fee is very expensive. I have sent several packages weighing about 1-2 kg to the United States. The starting price is 28.5 USD/1 kg. An additional 8 USD is charged for each kg over 1 kg. An additional 4.5 USD is charged for remote areas according to the zip code. This is the shipping fee calculation formula. FedEx delivery is efficient in 8-10 days.

$250 was the price for parts with shipping included

 

[barros57]

Reinstalled pump and this seems to have fixed the low power issue. The machine is now able to skid the tracks. However, one side is significantly slower. I checked the relief pressures at P1 and P2. They were both set to ~4200+psi. Should I set these back to the values in the service manual? Maybe the previous owner messed with these...?