Cat 980G Hydraulic Issue

Cat 980G serial number 2KR03683 Hey guys looking for some help with my 980g. It all of a sudden developed an issue with the hydraulics where the boom and bucket seem to work fine empty, but when you try to pick up a bucket full it makes noise and kind of stutters to pick it up. There’s no relevant codes on the dash and the oil level is good. Filters looked clean. We tested the pilot pressure and it was good, but when we tested the main relief we only got up to 800 psi when it relieved. The spec is 3000. Just looking to see what everyone else thinks if it’s likely a bad relief or if it’s a pump issue. I haven’t tried to adjust the relief or anything yet but I’m open to suggestions thanks.

CrusherRatN14 said: Filters looked clean. Click to expand... Were they cut open for inspection.? If not then that should be your next move.

Nige said: Were they cut open for inspection.? If not then that should be your next move. Click to expand... Didn’t cut them open yet. Will need to get new ones first

CrusherRatN14 said: Didn’t cut them open yet. Will need to get new ones first Click to expand... This VIDEO might be of some use.

Nige said: This VIDEO might be of some use. Click to expand... Thanks

Your main relief pressure is critically low. Spec for the 980G implement main relief is 20 700 ± 340 kPa (3 000 ± 50 psi). Reading only 800 psi explains exactly why the machine lifts an empty bucket fine but struggles, stutters, and makes noise with a full load. Most Likely Causes (ranked)

1. Main relief valve stuck partially open or contaminated Debris, a damaged seat, or a weak/broken spring will dump pressure long before it reaches 3 000 psi. This is the cheapest and most common first failure on these machines.
2. Failed implement pump (especially if it is the vane-style cartridge pump used on many 2KR-prefix 980Gs) A cracked rotor, worn rotating group, or severe internal leakage will not allow the system to build pressure. When the relief is adjusted all the way up and pressure still stays in the hundreds of psi, the pump is almost always the problem. Pilot pressure being good is useful — it rules out the pilot pump and most of the pilot circuit. Recommended Next Steps
3. Re-confirm the test • Gauge on the correct implement pressure test port (usually on or near the main control valve). • Engine at high idle. • Dead-head a function (e.g., boom raise or bucket curl against the stop) so the pump is forced over relief. • Oil at normal operating temperature.
4. Remove and inspect the main relief valve Pull it, clean it thoroughly, check the seat, spring, and poppet for damage or debris. Reinstall and retest. Many 980Gs have been fixed simply by cleaning this valve.
5. Attempt adjustment (only after cleaning) If the valve looks good, try adjusting it upward while watching the gauge. If you bottom the adjustment screw and still cannot get near 3 000 psi, stop — further adjustment will not help and the pump is the next suspect.
6. If pressure remains extremely low The implement pump is the primary suspect. On the vane-style pumps common to these machines, a cracked rotor is a frequent failure mode that produces exactly this symptom (almost no pressure under load). Do not keep trying to raise the relief setting if the pressure will not climb — you risk masking a pump problem and can damage other components. Serial number 2KR03683 is a standard early 980G, so the above pressures and failure modes apply directly. Start with the main relief valve inspection/cleaning; that resolves a large percentage of these “suddenly weak under load” complaints before you have to pull the pump.

ChrisMafera said: Your main relief pressure is critically low. Spec for the 980G implement main relief is 20 700 ± 340 kPa (3 000 ± 50 psi). Reading only 800 psi explains exactly why the machine lifts an empty bucket fine but struggles, stutters, and makes noise with a full load. Most Likely Causes (ranked)

1. Main relief valve stuck partially open or contaminated Debris, a damaged seat, or a weak/broken spring will dump pressure long before it reaches 3 000 psi. This is the cheapest and most common first failure on these machines.
2. Failed implement pump (especially if it is the vane-style cartridge pump used on many 2KR-prefix 980Gs) A cracked rotor, worn rotating group, or severe internal leakage will not allow the system to build pressure. When the relief is adjusted all the way up and pressure still stays in the hundreds of psi, the pump is almost always the problem. Pilot pressure being good is useful — it rules out the pilot pump and most of the pilot circuit. Recommended Next Steps
3. Re-confirm the test • Gauge on the correct implement pressure test port (usually on or near the main control valve). • Engine at high idle. • Dead-head a function (e.g., boom raise or bucket curl against the stop) so the pump is forced over relief. • Oil at normal operating temperature.
4. Remove and inspect the main relief valve Pull it, clean it thoroughly, check the seat, spring, and poppet for damage or debris. Reinstall and retest. Many 980Gs have been fixed simply by cleaning this valve.
5. Attempt adjustment (only after cleaning) If the valve looks good, try adjusting it upward while watching the gauge. If you bottom the adjustment screw and still cannot get near 3 000 psi, stop — further adjustment will not help and the pump is the next suspect.
6. If pressure remains extremely low The implement pump is the primary suspect. On the vane-style pumps common to these machines, a cracked rotor is a frequent failure mode that produces exactly this symptom (almost no pressure under load). Do not keep trying to raise the relief setting if the pressure will not climb — you risk masking a pump problem and can damage other components. Serial number 2KR03683 is a standard early 980G, so the above pressures and failure modes apply directly. Start with the main relief valve inspection/cleaning; that resolves a large percentage of these “suddenly weak under load” complaints before you have to pull the pump. Click to expand... Thank you

CrusherRatN14 said: Thank you Click to expand... I would suggest that you read his other posts and the responses to them before you start thanking him.

CrusherRatN14 said: Thank you Click to expand... You’re welcome, please read the rest of my answers. And let me know what you think. If any of them help you, I’m glad to have helped!

Nige said: I would suggest that you read his other posts and the responses to them before you start thanking him. Click to expand... I’m guessing AI answers lol

CrusherRatN14 said: Thank you Click to expand... You’re welcome, please read the rest of my answers. And let me know what you think. If any of them help you, I’m glad to have helped CrusherRatN14 said: I’m guessing AI Click to expand... But the big question is did it help solve the problem? Just because I don’t know every schematic off the top of my head, I know where to look and get you the information, I could have called the CAT dealer, I suppose anyone here could just call their dealer and find the information that way but it was after hours. If I can help does it really matter that I had to google a couple of things?

ChrisMafera said: But the big question is did it help solve the problem? Just because I don’t know every schematic off the top of my head, I know where to look and get you the information, I could have called the CAT dealer, I suppose anyone here could just call their dealer and find the information that way but it was after hours. If I can help does it really matter that I had to google a couple of things? Click to expand... The verbal diarrhea in Post #6 above is the diagnostic equivalent of throwing a shovel full of excrement at a wall. Some of it is bound to stick. As to assisting in a troubleshooting scenario I have my doubts. Being able to use AI research does not make one a good diagnostician.

Nige said: The verbal diarrhea in Post #6 above is the diagnostic equivalent of throwing a shovel full of excrement at a wall. Some of it is bound to stick. As to assisting in a troubleshooting scenario I have my doubts. Being able to use AI research does not make one a good diagnostician. Click to expand... Nigel Nigel Nigel, or he can chase around every, try this try that and take 6 weeks to arrive at the same conclusion that I gave you

Or he could perform a structured troubleshooting procedure starting with cutting the filter (or doing an oil analysis). I see your "solution" never mentioned that........

He said he didn’t want to do that until he had replacement parts, didn’t you read number 3? Or are you just throwing things out there to see what sticks?

ChrisMafera said: He said he didn’t want to do that until he had replacement parts, didn’t you read number 3? Click to expand... I did read Post #3, but that doesn't mean a detailed filter inspection (or an oil analysis) can be bypassed as a first step.

What’s going on Chris? You should go to the new member introduction thread and introduce yourself. You show up like the wind, like a bot with a case of verbal AI generated diarrhea, with TLDR responses. Do you have a cat? What kind of work do you do? Do you like C-store roller dogs? Are you into chubby gals? Tell us about yourself. Genuinely interested.

Coaldust said: What’s going on Chris? You should go to the new member introduction thread and introduce yourself. You show up like the wind, like a bot with a case of verbal AI generated diarrhea, with TLDR responses. Do you have a cat? What kind of work do you do? Do you like C-store store roller dogs? Are you into chubby gals? Click to expand... I believe the rules said if I made meaningful comments then I could have the opportunity to put in an introductory post, generally I’ve just been the punching bag for a bunch of guys. Just because I’m new here doesn’t mean I’m new at everything. I appreciate you giving me that advice though and I can come up with something that does give my resume and the reasons why I might know a thing or two about heavy equipment and might know where to look for things I can’t remember

Awesome! That’s the spirit. Good to have you on the HEF. If you are looking for a Forum, the HEF is where it’s at. Where topics never end. From old hoes to emission deletes, theres always a new trend.

I didn't find anything wrong with post #6. I've worked on and done inspections on 980B through 980M models and would likely do many of the same things. Whether not he worked on the machines or got the info out of a book or is a AI doing the replies, it doesn't matter as long as it helps solve a problem.