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980H Slow Bucket Movement

frankyakro

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Mar 25, 2026
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Ivory Coast
Update. Rubber hoses clamps and o rings change on brake and steering pump suction. Started and fan now running but still no brake pressure and no steering. The steering will turn in the cab with a little force but the rams don't move at all and no stress on the pump. I have no oil at the port testing area behind the cab when connected to either steering port. I have a steady but low flow from the brake port. Bucket is working fine.
 

Simon C

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I am probably wrong but you must have pilot pressure of some sort to be able to move the bucket. Maybe a Guru will be able to help with a hydraulic schematic.
Simon C
 

frankyakro

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Mar 25, 2026
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Ivory Coast
I have SIS and ET but im no expert on them. Im in a very remote location in West Africa and trying to get this machine sorted myself. On ET only active code i have is E284 LOW BRAKE ACCUMULATOR PRESSURE. But I still have no steering. Ive asked the guy who gassed the accumulator to come back but hes 2 weeks away at best. Maybe I damaged the pilot pump by not bleeding it correctly on start up but my bucket functions are correct. On the front of the machine i changed everything in the block that's fed from the pilot pump except one shuttle valve 251 7509, its held up in customs with another two rebuild kits for the brake accumulator valve and an implement ECU I dont need now.
 

Nige

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I have SIS and ET but im no expert on them.
Try this then. Get into SIS and look for the “System Operation” document relating to the functioning of the brake and hydraulic fan system. Once you can understand how the system is supposed to work it will help you tremendously in diagnosing WHY it’s not working as it is supposed to.

Post a photo of your SIS main page and I’ll try to help you navigate to where you need to be.
 

frankyakro

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Ivory Coast
Try this then. Get into SIS and look for the “System Operation” document relating to the functioning of the brake and hydraulic fan system. Once you can understand how the system is supposed to work it will help you tremendously in diagnosing WHY it’s not working as it is supposed to.

Post a photo of your SIS main page and I’ll try to help you navigate to where you need to be.
Thank, ive found the hydraulic diagram and ive seen a few things i need to check. I will keep you posted.
 

Nige

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Thank, ive found the hydraulic diagram and ive seen a few things i need to check. I will keep you posted.
You really need to find the document that describes how the system operates so that you can understand it first. Once you understand how the system is SUPPOSED to work this could give you some valuable clues on what might be going wrong.
 

frankyakro

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/You really need to find the document that describes how the system operates so that you can understand it first. Once you understand how the system is SUPPOSED to work this could give you some valuable clues on what might be going wrong.
You are right and I actually found them. However as you can see from attached image its saying oil goes from pilot to implement and then accumulator valve. But on my machine pilot outlet in teed with one side going to implement and one going to brake accumulator valve. Is it normal to see differences like this?
1000313467.jpg
 

Nige

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You are right and I actually found them. However as you can see from attached image its saying oil goes from pilot to implement and then accumulator valve. But on my machine pilot outlet in teed with one side going to implement and one going to brake accumulator valve. Is it normal to see differences like this?
I see that as basically two ways of saying the same thing. From a hydraulic perspective it doesn't really matter if the tee is right next to the pilot pump or mounted on the implement valve, the end result is the same.

I don't see anything there related to the operation of the hydraulic fan.

Can you upload a copy of the hydraulic schematic please.?
 
Last edited:

frankyakro

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Mar 25, 2026
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Ivory Coast
I see that as basically two ways of saying the same thing. From a hydraulic perspective it doesn't really matter if the tee is right next to the pilot pump or on the implement valve, the end result is the same.

I don't see anything there related to the operation of the
The fan is working fine now. The bucket actions are good. I have 500 psi at the implement block and 500 psi at the steering pilot valve input but still no steering. I will check the steering pilot valve output Monday. Am I right in saying that my brake and steering issue are not related if my pilot pump is okay?
 

frankyakro

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Joined
Mar 25, 2026
Messages
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Location
Ivory Coast
I see that as basically two ways of saying the same thing. From a hydraulic perspective it doesn't really matter if the tee is right next to the pilot pump or mounted on the implement valve, the end result is the same.

I don't see anything there related to the operation of the hydraulic fan.

Can you upload a copy of the hydraulic schematic please.?
I will upload the schematic tomorrow, thanks for all your help.
 

Nige

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I have 500 psi at the implement block and 500 psi at the steering pilot valve input but still no steering. I will check the steering pilot valve output Monday. Am I right in saying that my brake and steering issue are not related if my pilot pump is okay?
Not knowing what the spec is for the pilot pressure it's hard to say one way or the other. What is the pressure supposed to be.?
 

Nige

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Its 500 psi
In that case what you have on your machine is correct as per specification.

I will check the steering pilot valve output Monday. Am I right in saying that my brake and steering issue are not related if my pilot pump is okay?
A quick look at the schematic shows that the brake and steering systems share no common lines, therefore I would say you are correct. You need to find the test & adjust procedures for the steering system and start to work through those.
 

frankyakro

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Thanks for confirming. Can you see a link with the pilot circuit and the fan that would explain why I lost the fan. I know its okay now but I would not want that to occur down the line and overheat the engine.
 

Nige

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Thanks for confirming. Can you see a link with the pilot circuit and the fan that would explain why I lost the fan. I know its okay now but I would not want that to occur down the line and overheat the engine.
I recall that there used to be a fitting somewhere on the fan system that had a built-in screen which, if it got partially plugged, would reduce fan speed. This may have been on a different model but without access to the Parts Manual it's impossible for me to confirm.
 
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