We are working on a cat 980g 9CM machine that we had a very bad boom that needed replacing. We replaced the levers too. and rebuilt our cylinders, but when installing the boom we noticed it had a problem in the curling of the bucket. We decided to measure the boom only to find it is 6 inches longer than the original boom. the original measured 99" center hole to center hole where the new one measured approx. 105 from the same points. We looked everything up in the CAT system and diagnosed that the new boom should have worked. all of the surrounding parts we identical. levers, cylinders, links, everything was the same. the only time parts changed was when you went to the high lift boom which measured 128" from center to center. We are not sure why is not working properly and we neding some help with diagnosing the problem. Please help, Stranded Lonely Parts Man.
Sounds like you need to talk to your cat product support rep. Is there any chance the old arms had been modified?
No. We do not think the old arms were modified. But we are not sure why they offered two different part numbers for the standard boom in the first place. unless the had an additional function that we are not aware of. Our CAT rep. has not been able to help. After ready some other similar problems, im wondering if its not a solenoid stuck or something else completely different not pertaining to the boom themselves.
Which measurement are you talking about, L1.? I see options for L1 on 980G of 122.2", 127.6", & 133.9" and quite a few different Part Numbers. Is there a metal plate on the RH leg of the Lift Arm maybe 12" back from the bucket pin bore.? If so it should have a Part Number stamped on it. If not look on the centre cross-tube casting for a Part Number.
our is the L-1 measurement. the old one is 99" and the new one is 105"...the ones you are showing look to be for a hi-lift. but, i will see if i can check metal plate for some better identifications.
I just copied a representative diagram from a document about lift arms. It's not intended to look exactly like yours,, simply to confirm that we were both talking about the same measurement.
Your drawing looks right. in the drawing your posted about 30 minutes ago.
A Part Number would be key. If one was available from both Lift Arms better still.....
I can see at least 8 different Lift Arm Part Numbers for a 980G, but none of them have an L1 measurement centre-to-centre of the pin bores at the extremities less than 122". So I have no idea where the 99" of the original lift arm came from, nor the 105" of the replacement. This isn't an underground machine by any chance is it.? They use some weird and wonderful Custom Shop parts,
The two part numbers i have are 115-7044 and 115-9660. can you tell me the lengths from c to c on the bored pins holes?
The 115-7044 Part Number is a discontinued Custom Shop Lift Arm. It is/was part of the 4Q-1733 Custom Machine Conversion Arrangement for Block Handling. That explains why it is so short. The BOM for 4Q-1733 also contains an extra counterweight. I cannont find any measurements for it. 115-9660 is not just a Lift Arm but a High Lift Arrgt with a 6.3" extended Lift Arm. The Lift Arm contained in that arrangement is a 124-7804. It should measure 133.86" centre-to-centre on measurement L-1
Can you share a machine Serial Number.? Then I can take a look at how it was originally built. On top of the additional counterweight the Block Handling machines also had a different rear chassis and a Heavy Duty transmission.