Cat 304 wont swing or walk

[OMDKprop]

Been super busy with work the past few weeks so i haven't had a chance to get much done on the machine until today. I had my buddy from volvo come take a look at it we got most of the electrical gremlins sorted out. Now everything electrical works with the exception of the water/temp guage. He feels that there is a good possibility the machine is airbound due to being run with next to no fluid. Or the pilot pumo is junk as others have suggested. He thinks this because when checking for pilot pressures he cracked one if the lines loose on the block for travel while having me put very light pressure on the pedal and a massive amount of air came out and then the track jerked forward under full power for about 3 seconds and stopped, which is the only track movement I've had with this machine since buying it. The machine barely has enough power to swing right but when swinging left moves better/faster, although still nowhere close to where it needs to be. Is there a procedure to bleed the hydro system? Should i consider cracking all the lines loose one by one and trying the individual functions to attempt a bleed? Could something else cause air to enter into the system when it shouldn't?

 

[uffex]

Good day
Please see attached maybe helpful.
Kind regards
Uffex

 

[OMDKprop]

So to update everyone I've finally made some good progress on the machine. The short answer to my issues was 2 hoses off the travel block that were swapped. Everything now functions but what i thought was the pilot pump is looking like a swing pump that also is the supply for the main swing, swing boom, and blade all of which are still very slow and weak. Gunna dig into it more this afternoon but as of now technically everything works and the machine moves.

 

[OMDKprop]

Ok guys this should hopefully be the final update on this issue/problem. After getting the swapped hose issue sorted out i had my buddy from volvo come down to do some pressure testing. We confirmed that the small gear pump off the main pump is infact directly tied to the slew, swing/offset boom, and blade circuits. As mentioned before these functions were all extremely slow and weak. When pressure testing that pump it only put out 180-200psi and from my research should have been around 400psi. I called CAT and they could have it to me next day for $104 out the door. Well today i swapped it out and am happy to say the machine appears to be fixed. Only thing left to have it fully functioning is to order a new 2 speed switch that i may or may not have mangled in the teardown process. I suspect the gentleman i bought it from was honest in saying that he blew a hose underneath the machine and could never get it figured out. as a result i think he ran that smaller pump dry damaging it. His mechanic or whoever took the machine apart and when putting it back together not only crossed some hoses but pinched a few o rings causing the machine to now not move, **** fluid, and have weak functions which ultimately were not expensive or very time consuming to rectify after identifying them. Thank you for all the advice, opinions, and suggestions as they were all extremely helpful. The $3k caterpillar is now back in action for under $1k

 

[Nige]

Always nice to hear a success story.
It can be a real hair-tearer when you weren't the one who pulled the machine apart so you have no idea what was done before you got your hands on it.

 

[nonprod]

Hello Nige - I was snooping around this post about Cat304cr, on account I have some electrical spaghetti to sort out myself, on machine NAD04265 - Any chance you have that schematic you're referring to here that you can share (again) ?

TIA - gibbs

Schematic on the way.

 

[Nige]

Hello Nige - I was snooping around this post about Cat304cr, on account I have some electrical spaghetti to sort out myself, on machine NAD04265 - Any chance you have that schematic you're referring to here that you can share (again) ?

Keep an eye on your messages. It's a different schematic because your machine is a higher Serial Number, but it's on the way.