cat 830mb veitnam scrapper

[chris allen]

is there any one out there that has any knowledge of these big guys, ive got one that I ran across an purchased for pulling an forestry chopper around, well the tractor didn't come with the blade nor the pan (bowl) but its all plumbed for it, were trying to figure out the hyd. lines that are mounted behind the cab that ran to the pan, were wanting to figure the lines out so we can have 3 differ hyd service outlets for differ uses, theres not many of the tractors out there nor was there many made, an when ya speak to cat about them there clueless an deny there even a cat product.:Banghead these tractors are like rideing on the bak of an elephant, they can crawl an then when ya kick em in the tail they ll fly.

 

[fixou812]

Any picture's Chris?

 

[Bob/Ont]

Chris ask about an 87A 988 loader, they are very similar just turned around. To figure out circuits hold capped lines and have someone pull the levers.
Later Bob

 

[chris allen]

don't have any pics of our machine,, other than the valve that we ve been questioning, but if ur interested in the 830 mb look it up online, there really neat looking an were built tough

 

[chris allen]

we have all 6 lines capped off with quick disconnects ,,, when ya pull one control, ya ll see the line jump an dead head, an when ya go to another function an dead head it ya will see 2 lines jump, I have played with it an found out that if I use one of the big (1 inch) lines an use the lower mid size line (3/4 inch) lines I can get a cylinder to move in an out (just a cylinder with lines an quick disconnects for testing) so I marked both of them lines together as one circuit , so then I picked up another big line an an the other mid size line an though ok this mite be the other circuit , needless to say the cylinder moved out a lil but wouldn't retract back. its like when ya pull other levers it ll also pressurize more than one line. its very mind boggleing here a pic of the control valve, all the 3 metal lines that are together are the 3 outlets that went to the pan, an theres one big line on each end of the valve kinda by itself, im guessing there the pump press an return line, an the line in the lower center of valve is one of the 3/4 inch lines

 

[chris allen]

you would think with this being an old tractor it should have 2 lines per control valve for each spool, but then again all 3 valves are made into one big control valve with 3 spools in it, sorry pics uploaded sideways

 

[68M]

You've got a standard Caterpillar control valve, Caterpillar run a common return line on their scrapers, look at any(scraper), there is only four hoses that go back to the bowl for the six functions. When you operate the levers one way the oil in the other end of the rams returns in the common return. when you operate the levers the other way oil pressure goes back through the common return and acts on all of the rams. The only one that will move is the one that you have moved the spool on, all other rams will not move because the other spools are closed. It is confusing until you understand the system. All Cat scrapers are like this, four hoses for six functions.

 

[chris allen]

im extreamly glade you understand this kinda valve, so does this mean I can not iscolate each of the three control valves an have 3 differ quick disconnect funtions (meaning 2 hoses per funtions) because I do have 6 total lines behind the cab . thanks again for ur input aswell

 

[Delmer]

The way I understand it, yes you have three functions with two hoses each. Think of it like a common ground for your electrical system power going out is switched, and power coming back is switched too, just on the hot side.

The six total lines behind the cab are confusing you, you need the three "switched" lines and the one "common ground" coming out of the valve bank.

 

[1965IHdiesel]

Sounds like these fellas have you going in the right direction, so hope this doesn't confuse you more We have a Clark 290m, (same sort of style of military scraper tractor as your 830) and the bowl lift/lower circuit has a float position, just something to keep in mind when your testing. I think on ours if you hold the lever all the way its in float. Not sure if the 830's were the same, but might explain why you get a cylinder seeming to only move one way. On ours you can feel the detent in the lever when you move it around on that circuit. Hope this helps!

 

[Delmer]

Dang, I'm gonna have to think all day to figure out how THAT works. Oh forget it, not my problem...

 

[chris allen]

yea im bout concluded that I have one return line an 3 pressure lines,,,, but then again why do I have 6 lines total tho, 2 in 2 3/4 in an 2 1/4 in lines 3 pairs

 

[chris allen]

glade to hear someone out here other than us has one of these guys, do you have the pan (bowl) with urs,,, ours came with one hydr. cylinder an cable an tow arms on rear, tractor was set up like a wrecker or tug boat to just move stuff around with it, ours didn't even come with front blade. mine does have the detent in the valve like urs,, do you use it as a scrapper? or a tug ? do you have any pics of urs or hydr hook ups? called cat were I use to work an there all clueless, called another cat place an they were lost too

 

[chris allen]

figured out the situation I was having,,, thx guys for all ur help an advice