bought a 920 cat, engine seized 20 min later.

[Labrador-tractor]

block heater finally showed up so I got that installed.



Then I tackled the pin, first I had to remove the coupler to clean the junk out of the bore.




the bore was ALOT worse then I thought, other side was actually good shape but this side is toast. if I do end up using this machine long term I'll end up machining a new boss to weld into the boom.



yesterday was much warmer then usual for us in Dec so I ended up working on my other cat... the snow cat! fuel tank was rusty so a while back I pulled the tank cut an end off and cleaned it out. so with the warm day I stuck it back in, not exactly a fun job! the rad has to be moved to get to the front 2 bolts and the rad bolts are miserable to reach.

 

[Labrador-tractor]

finally got a chance to push some snow yesterday, we got a pretty good dump on Wednesday and looks like another coming tomrrow. the 3304 started fine at-10C/14F with no block heater which is no surprise thats pretty warm temp's, I did have some issue with ice in the fuel shutoff valve in bottom of the tank but some fuel conditioner fixed that. and the window in the door shattered when I closed the door so I'll need some glass cut now.

one day I'll have to bring over the Hough and the John deere to line em all up.

I also really need to get the lights working on the 920, most of the winter here it's dark before 5pm so Lights are necessary! that last picture was taken around 5:30. But wiring is my least favorite activity in the cold...

 

[Labrador-tractor]

forgot to take pictures but I did some more upgrades on the 920. to operate the quick coupler they had a closed center valve in the cab to operate the CYL on the coupler, but for a supply the tied into the plug on the transmission filter cover and the return T'ed into the trans filler tube. My good buddy who was around these when they were new said thats how they did a lot of cats around here... why I don't know because it works terrible! mine worked awful and the other 920 I've ran with the same setup also didn't work very well. I thought about tapping into the curl back circuit like komatsu does but my parts loader had a 24V hydaulic power unit to run the coupler so I robbed that and swapped it over, this way if I find a snow plow with hydraulic angle I can use it to run the blade as well.

I was also VERY supprised last weekend when I was clearing snow that the return to dig bucket leveler started working!!! of all the old cats around here I've seen ,ran and worked on with the hydrauilc kickout this is the first one I seen work, so when that lever kicked foward as I was backing up from the snowbank I got way more excited then I probably should have haha. I had every intention of trying to fix it this summer and expected a rusted master cylinder, bad lines etc etc all the crap you would find from basically a hydraulic brake system that sat for maybe 30 years.

I also got all the lights working with the current wiring. its a god awful mess so the summer I'm ripping it out and starting over. I even cleaned out and 'detailed' the cab with my favorite heavy equipment detailer... good ole WD40.

and just because everyone love pictures so heres some related and unrelated to the 920.

few weeks ago i put the 920 to work moving my sisters cabin, built a steel skid under it and pulled it with my 920 and my buddies komatsu WA200





last weekend I did see the First otter of the year down in the river in front of my camp.




and the snowmobile developed a coolant leak so it gets some shop time, the rooster approves.

 

[1693TA]

Well, since the rooster approves, It's all good.

 

[Labrador-tractor]

Yup, he don't approve of much lol his days are numbered actually, ended up with 4 roosters. I have one barred rock rooster, I'm keeping him so I can hatch some more eggs this spring. the other 3 are going in the freezer.

 

[Welder Dave]

What do you mean by a closed center valve?

 

[Labrador-tractor]

when the valve is neutral no fluid passes through from the inlet to the outlet, its dead headed basically. in this case robbing transmission pressure its critical because if it was a 'normal' open center valve that flows freely between inlet and return when the spool is neutral you'd have no transmission pressure. same with tapping into the curl back circuit like I talked about, the hydraulic oil would bypass through the valve taking the path of least resistance rather then move the cylinder.

modern Hydraulics use closed center valves quite a lot these days with piston pumps that adjust flow depending of the demand. old stuff like this 920 and simple stuff like a log splitter usually use good ole open center valves and fixed displacement pumps like gear and vane pumps.

 

[Welder Dave]

I was wondering what happens to the trans. pump/oil if it's dead headed at the valve? Does the trans. act as a closed center system? Not familiar enough with how the trans. works but seems like it would be hard on the pump and/or the trans.. A selector valve off the bucket curl would seem like a much better way to do it.

 

[Labrador-tractor]

The plug it was tied into on the filter is a test port I'm thinking so it's normal blocked off, so when your not operating the coupler everything with the transmission works as normal. While using the coupler you are using whatever pressure is in the filter housing. I'm honestly not 100% sure how the trans is setup but assuming it's line pressure at the filter then however many psi the trans uses to operate the clutches that's whats available to run the coupler. Whatever that is is not many psi by hydraulic standards because it was gutless lol.

I could be wrong but cycling the coupler while driving could possibly cause a drop in line pressure and maybe cause some clutch slipping to. A friend of mine also made a good point, he said he wonders how many transmissions got burned up from a leak on the coupler causing the trans to run low on oil, we all know checking the transmission oil can get overlooked a lot.

Tieing into the curl circuit is definitely a better option in my opinion. Or run a 24v pump like I have now, I've seen that on a few machines around here.

 

[Tugger2]

What a great thread.Your work and resourcefullness is very impressive.But your patience on this project is incredible.Good work!

 

[Labrador-tractor]

What a great thread.Your work and resourcefullness is very impressive.But your patience on this project is incredible.Good work!

Thank you! I like to actually fix things rather then throw money at stuff and playing parts changer. if I did a full rebuild with all new parts would it last longer? yes for sure! BUT... this loader will probably see 50ish hours a year, I'm confident the parts I reused will last me many years to come. as for patience Ive been working on "junk" my whole life so I know the game haha its when I spend a decent amount of money on stuff thats supposed to be good and it ends up being junk that my patience runs thin.

 

[Welder Dave]

It also helps if it's relatively easy to get at the things you need to repair. Also if parts are small enough you don't need a crane or helper to pick them up. My 931B and most skid steers can be a pain to work on some things. The starter on the 931B is especially annoying to R&R. The belly pan is too because you have to crawl under to get the 2 bolts at the back. On a wheel loader at least you don't have to work on the ground.