428C struggling to lift front boom

[heymccall]

If it didn't have the updated parts, the grooves would be too narrow to fit backup rings.

 

[Nige]

Good point. Just because by Serial Number SIS shows the updated parts doesn’t necessarily mean that the machine was actually built with them.

Just out of interest it might be an idea to pull one of the easier-to-remove resolvers and see whether or not the backup ring will fit in the groove.

 

[heymccall]

Yup, visual verification. The only sure way.

As an aside on serial number breaks....
I had a 325CLCR, BKW00334, with 3200hrs, shear the hydraulic pump input shaft, which I've never seen on a working pump.
Turns out that there was a bulletin covering BKW00001-BKW00328, so it "supposedly" didn't apply. Turns out that several components were mismatched to the setup, including the balancer (damper?).
Ran with new pump and updated parts until she burned a hole in a piston @ 9k hours (injector failure).

 

[Pralhad Birdi]

Yep the grooves are too narrow to fit the back up rings. I suppose I'll just have to have a few o rings on standby in case it ever happens again.

 

[clifford baxley]

Make sure you also check that the balls aren't stuck while you are in there.....

Hello Nige. My name is Clifford Baxley. I just joined this forum but i have seen and read a lot of your answers. I am working on a 416C Cat backhoe. I changed the hydraulic filter and afterwards the steering has been giving problems. The only way to get power assist is to raise the front bucket to its highest point. I talked to a Cat tech and he told me there was not anyway to bleed the system. It seems like that is the problem but i don't know. If you could help i would appreciate it very much. Thank You

 

[Welder Dave]

Hello Nige. My name is Clifford Baxley. I just joined this forum but i have seen and read a lot of your answers. I am working on a 416C Cat backhoe. I changed the hydraulic filter and afterwards the steering has been giving problems. The only way to get power assist is to raise the front bucket to its highest point. I talked to a Cat tech and he told me there was not anyway to bleed the system. It seems like that is the problem but i don't know. If you could help i would appreciate it very much. Thank You

You might want to make a new thread and then the whole group of HEF members can see if they can offer any assistance. Nige is very knowledgeable but maybe not quite as much as some others on the smaller equipment.

 

[heymccall]

He did start his own thread. He has a stuck or bypassing resolver.

 

[Nige]

All the answers you need are on Pages 1-3 of this thread. As HMC said on your earlier posting in another thread you have the classic symptoms of a resolver valve sticking. Take them all out one at a time and reseal the lot is my suggestion.

If you want help regarding confirmation of Part Numbers for seals, etc, I suggest that you post a machine Serial Number on your other thread.

 

[Welder Dave]

He did start his own thread. He has a stuck or bypassing resolver.

Didn't realize he made an earlier thread. Saw his post and thought he was only looking for Nige's help and thought others could also offer assistance.

 

[adilf]

Quick update:
I was speaking to my dad, and he said this machine brought a similar issue about 12 years back (before my time). At the time, a hydraulic mechanic from apparently got under the machine, changed some tiny o rings, and within about 15 minutes, it was back to normal.
Of course he didn't say exactly what he had done, but does anyone know whether there's anywhere on the machine that such o rings would go, and if so, could it be solved by changing them?
I'm literally clutching at straws here, but I'd at least like to eliminate the possibility before doing anything too expensive.

hi under need the TLB bei the rear rigth wheel in front of the rearaxel boltet into the chassie is a valveblock with a pressure setting rod. lossen the looknut and turn the rod in a quatter or half a turn. look the nut again not do hard and work the tlb. noemaly dat das the trick. i am sure dat is wath your mech. has done. good luck.