Backhoe hydraulic leak

[Jack L]

All I know about the hydraulics on my 4130 would fit in a teaspoon. Everything has been working well. I did have to replace two hoses on the loader but now I have a leak on the hoe. I believe it's a model 712. When I swing the boom left the cylinder on that side leaks through the vent. I'm not sure what the cylinder is. My old installation books shows it but doesn't identify it.

What do you guys think is causing this?

Thanks in advance.

Jack

 

[john_Bud]

The hoe is a 713 or possibly a 723. 712 was a loader used on the HD industrial machines.

The swing cylinders are single acting cylinders, but are single acting on retract. The vent is there to push out any fluid that got past the seals.

If you are getting fluid there, the seal is leaking. The cylinders possibly have rust pitting from moisture accumulation leading to the leaks. (mine do). You will have to remove the cylinders and have them rebuilt or else rebuild them yourself. It's not rocket science, but it does take some larger tools. Cost to have it done varies from maybe 50 bucks for a real cheap place to maybe several hundred each. The cost of replacement seals is 25-30 bucks on the low side to 50-60 on the high.

The cylinder uses VEE seals. The cylinder seals are 3/8" wide and the stack is 1" tall exactly. So if your cylinder is 3&1/2 inch the seals are 3.5x2.75" and the stack is 1" tall. It's a mix if hard and soft VEEs. The cylinders are either 3 1/2 or 4" or 4 1/2. for the 10', 12' and 14' hoe's respectively.

The rod seals are 1/4". So if you have 1 1/2" rod diameter, the seal is 2.0x1.5x1" tall. Again, a mix of hard and soft urethane. There are also spacers and wear rings that will need to be replaced and the rod wiper.

If none of that makes much sense, you can either get some learn'n or spend some bucks. I chose to get the learn'n and a couple special tools to disassemble the cylinders. Well, I made that choice after paying to have one done and didn't like the projected cost of doing more!! It's not rocket science which is good as even I was able to learn how.

If the leak is just a squirt every now and then, you can put a small NPT tube in the vents and run clear poly tube from them to a bucket.

 

[Jack L]

Thanks for the detailed information John. The hoe is a 723 which I can't remember because I confuse the two.

I plan on taking the hoe off before winter and that would be a good time to do the rebuilds. I don't mind doing the work myself if there's no time constraint.

I'm presently learning about Ford flatheads with my latest project.

<a href="http://s135.photobucket.com/albums/q121/JackL_06/?action=view&current=P7260047.jpg" target="_blank">

</a>

Thanks again John,
Jack