4500 backhoe leaking under load

Well guys shes got a bad leak now. As I was digging this morning I look down and I see a steady steam pissing out from the lower area of the backhoe mount. So I finish up with it and park it and look for blown hoses. I cant determine where its coming from. Theres fluid everywhere,.. Only thing is, everything works fine and is only barely dripping when I'm down there looking at it. I carefully tried everything while looking under there but cant determine exactly what was failing. So I need some recomendations as how to pinpoint what to replace. Next I'm going to remove the hoe to fix whatever it is. So my plan to remove hoe is stretch hoe all the way out flat. Lower outriggers onto pads and just barely take some weight off. Loosen to big nuts that hold rods that tie backhoe onto mounts and move rods out of the way. Use outriggers to lift hoe frame above hooks that that hold it. Drive tractor 4 inches forward and chock wheels and turn off. Undo 3 hydraulic lines that run hoe. Hopefully attach to smaller hoses together because they are positive pressure? Plug up end of bigger hose with something? Dive tractor away and park. Cut big piece of pine to right size to put block under hoe frame so that I can relive pressure from stabilizers and not get killed while working on hoe.

How can I find leak and hows my plan sound? Thanks so much for any help

You've got the idea on taking the hoe off. The small diameter hose is used to loop the hard lines on the tractor. It's a pressure line and could see high pressure. The larger one is the return line and that is normally used to loop the hard lines on the hoe to keep crud out.

I would try to find the leak location first if possible. It may be the swing cylinder, boom cylinder, cushion valve or even the controls. That's a fair amount of ground to cover blind.

jb

You have outlined the way to properly & safely remove the hoe.

But FIRST, find the leak, while you can still put pressure on the system.

~~HB~~ in NC

Got the same thing happening w/ my 3500. It appears to be the side-to-side cyl. Hard to tell cause you can't see where the lines hook up under there.

The other guys are right about being sure of the leak location first. You may need help to so that one can look while the other loads.
It's very possible that you'll find that it can be fixed without removing the hoe; I've fixed many leaks in that area over the years and haven't taken the hoe off yet.
Good luck, Wm

The others are right; find the leak first. All the cylinders are easier to repair with the hoe still attached except the swing cylinders. If it is one of the swing cylinders it is easier to unbolt the hoe, unhitch it using the stabilizers (but still leave the hydraulic hoses attached) and move the tractor forward about a foot. The hoses will be tight but you can detach the swing cylinders with minimum hassle (I know all this because I just did it). First, however, do this... With hoe still attached and stabilizers set; Extend the hoe to maximum reach (on level ground) but don"t let the bucket touch the ground. Swing it almost all the way to one side. Turn off the engine. Crack open the OPPOSITE bleeder screw on the combination valve (if the hoe is swung to the right crack the left bleeder), then by hand push the arm all the way to the other side then back to middle. Close the bleeder, start the tractor, lower the boom and detach the hoe (DO NOT TOUCH THE SWING CONTROLS DURING THIS). This way the swing cylinders will be extended and the chain will be loose for easy detachment and reattachment.
One of my cylinders had a nasty gouge in it causing a leak. On recommendations from the ingenious folks on this site I filled the gouge with acid core solder, filed and sanded it down smooth and replaced the seal. It has been working perfectly since.

Jim

it's a high pressure leak most likely in one of the swing cylinder supply lines. thats where i found mine.those lines get moved around when operating and the rest do not. hope this helps.

(quoted from post at 10:37:57 04/27/09) it's a high pressure leak most likely in one of the swing cylinder supply lines. thats where i found mine.those lines get moved around when operating and the rest do not. hope this helps.

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I think your right,.. Thank all you guys for the replies I got under there and moving everything carefully nothing really jumps out at me. Everythings wet What do you expect for a 35 yr old machine worked hard and put away wet. I got it last year and have worked the snot out of it. I did all regular maintenance to it when I got it. But now its time to give back a little and fix her up some. Iknow the swings are leaking cause if I'm working it about every 2 hrs the chain gets loose and I have to pop the breather line off and drain a little fluid out to tighten the chain. I think I may have hurt something the other day when I took the breather line off and swung to hoe fully in both directions to get all the fluid out, Maybe I forced some thru the seals or damaged a line? I cant see anything in there where they are and I keep banging my head looking in. I think its safe to say that I should pull the hoe off and rebuild the swings, inspect the lines and theres at least 2 lines above where the outer layer has rubbed through and split that I know need replacing. Of course they should all be done but I just dont have endless money to throw at her but I do have time

So has anybody ever rebuilt the swings, easy or what? Whats holding those in there, nothing? I have the manual but either I'm dumb or the manual stinks, too complicated. I appreciated the trick to loosen the swing, I take it the bleeder screws are on each side and look like brake bleeders? I should get them soaking now so I dont break them off,..

Again thanks so much for the help guys

I did the swings in my 3400 with a 753 BH. Easy cylinder to remove and rebuild without removing the BH. I did have light corrosion in the bores but cleaned it up and put new seals in, that was three years ago.
Someone once mentioned centering or return springs in them, mine had no springs. They're single acting opposed cylinders.

Once you unhook the swing chain and disconnect the hydraulic line you can pull out the cylinder, they just sit in there.

Are those bleeders actually vent nipples? Because the the cyls are single acting one side of the piston is vented. usually the cyls are vented to each other creating a closed system preventing dirt and moisture from getting in.

(quoted from post at 09:50:06 05/10/09) I did the swings in my 3400 with a 753 BH. Easy cylinder to remove and rebuild without removing the BH. I did have light corrosion in the bores but cleaned it up and put new seals in, that was three years ago.
Someone once mentioned centering or return springs in them, mine had no springs. They're single acting opposed cylinders.

Once you unhook the swing chain and disconnect the hydraulic line you can pull out the cylinder, they just sit in there.

Are those bleeders actually vent nipples? Because the the cyls are single acting one side of the piston is vented. usually the cyls are vented to each other creating a closed system preventing dirt and moisture from getting in.

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Hey Dave, thanks for that, I got to get to it, maybe this week, the Mrs and her sister need me to do some digging

(quoted from post at 14:05:08 05/10/09)

(quoted from post at 09:50:06 05/10/09) I did the swings in my 3400 with a 753 BH. Easy cylinder to remove and rebuild without removing the BH. I did have light corrosion in the bores but cleaned it up and put new seals in, that was three years ago.
Someone once mentioned centering or return springs in them, mine had no springs. They're single acting opposed cylinders.

Once you unhook the swing chain and disconnect the hydraulic line you can pull out the cylinder, they just sit in there.

Are those bleeders actually vent nipples? Because the the cyls are single acting one side of the piston is vented. usually the cyls are vented to each other creating a closed system preventing dirt and moisture from getting in.

Click to expand...

Hey Dave, thanks for that, I got to get to it, maybe this week, the Mrs and her sister need me to do some digging

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Good luck with it. I had to pull my pump today, I think a have a vane or two stuck from sitting all winter.

Well I got the hoe off, still connected, it wasnt too bad. Now I cant get the swing cyl out. Seems like its stuck in there. It wiggles up and down but wont pull out. I got the chain disconnected on one side and was going to try to get it to push itself out but it will only go in and now chain on other side is tight. So its stuck and I'm stumped.

(quoted from post at 17:53:23 06/02/09)
Well I got the hoe off, still connected, it wasnt too bad. Now I cant get the swing cyl out. Seems like its stuck in there. It wiggles up and down but wont pull out. I got the chain disconnected on one side and was going to try to get it to push itself out but it will only go in and now chain on other side is tight. So its stuck and I'm stumped.

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Hmmmmmm, The swings on mine had a neck that slipped into a machined or cast fitting, tension on the chain was the only thing holding them in place.
I havent been around to many of these so I cant say if they're all the same.

I figured out my pump problem, I stripped out the splines in the drive hub for the pump. The new parts (ordered from this site) showed up yesterday.