H Cylinder Repair

[idaho04]

One of the H cylinders on my Bradco backhoe is leaking. Last time I needed to repair a cylinder seal I brought it to a local shop and paid $70 for the repair. I was thinking that I could do it myself. Here are my questions:
Where can I get the repair seal/kit? How do I determine which seal (size, type) I need? How do I open it? Where do I find out how to open it? Any oter hints/suggestions?

Any help appreciated.

 

[TedLaRue]

One type of hydraulic cylinder uses a "tie rod" design. It has three or four long bolts (tie rods) running the length of the cylinder (on the outside of the cylinder where they are plainly visible) holding end-plates onto the cylinder.



It's pretty obvious how to open those, so I'm guessing your cylinder has a "gland nut" (keep your mind out of the gutter!) on the end that the rod (I said, keep your mind out of the gutter) extends from. The gland nut has two holes in it. A special wrench spans around the rod and has pins that fit into those holes. I found one for sale in a local business that caters to industrial folks but sells to individuals too. I just now found one on the net for $16.22 + shipping, pictured below. The website is (as of 08/08/2007)

Auto Parts and Automotive Tools


Note the square hole for inserting a ratchet or breaker bar.

Installing the seal kit is pretty straight forward, but first check the cylinder walls and the rod for scoring/scratches. If either are damaged, the new seals will just get eaten up. You might be able to sand out minor scoring with emery cloth. But if you have deep scoring you'll have to replace them (or just buy a new cylinder). Remove the old seals and lay them out in order, then install the new ones in the same order.

Finally, after the repair, be sure to remove and clean your hydraulic fluid strainer. You may have to do that two or even three times (maybe 15 usage hours apart). When the seals failed, they may have contaminated the hydraulic fluid with very small bits and pieces of the seal, especially if the cylinder or rod were scored.

I ordered the seal kits I needed from the manufacturer of the cylinder because it was convenient, but you should be able to take the disassembled cylinder to a local place that sells seal kits and have them match it up. Check your yellow pages under hydraulics. Some NAPA shops do hydraulic work and sell hoses/fittings.

 

[Soundguy]

I like to do stuff myself.. but on big cyls.. it pays to have a pro do it unless you already have the tools and know how. Sometimes the gland nut just won't come off with 'normal' man sized tools.. etc..

Soundguy

 

[john_bud]

I like to do stuff myself.. but on big cyls.. it pays to have a pro do it unless you already have the tools and know how. Sometimes the gland nut just won't come off with 'normal' man sized tools.. etc..

Soundguy

That's why I have a 4' cheater bar. It also helps to hang my 220# off the end of the cheater and whap the cheater with a 3# hand maul. The shock will loosen it up.


BUT, I don't think that the cylinders on a Bradco are bigger than 3 or 3-1/2" bore. Just loosen the gland nut or cap while the cylnder is still on the hoe. You will typically need an impact or cheater bar for the piston nut.

H&D Distributors, Inc. Your Complete Source for Seals will have the seals. Decent prices and fast shipping.

They have a great PDF catalog with pictures. about 10 meg download.

 

[idaho04]

Thanks, Bud. The cylinder is 3" but quite ling. There are no obvious nuts on it but there is a slit near the end. What kind of tool do I need for it and what kind of motion do I do? Are there any pictures of the cylinder to look at? Once I see one open I'll be able to figure out how to do it.

 

[Soundguy]

Post a pic of it.

Soundguy

 

[tlbuser]

Thanks, Bud. The cylinder is 3" but quite ling. There are no obvious nuts on it but there is a slit near the end. What kind of tool do I need for it and what kind of motion do I do? Are there any pictures of the cylinder to look at? Once I see one open I'll be able to figure out how to do it.

The slit is for accessing the retaining ring. You need a spanner wrench to turn the gland nut CCW until you can see the end of the ring. Pry the end of the ring out then continue to turn the nut. Once the ring is removed, pulling on the rod end will allow the rod assembly to be removed from the cylinder.

 

[idaho04]

Here is the picture of the Bradco cylinder to repair.

 

[3RRL]

Ted,
Thanks for the link to the gland nut wrench. I've made some using round stock and dowel pins but this one is really handy.

 

[TedLaRue]

3RRL wrote: Thanks for the link to the gland nut wrench.

Rob, This site is great for sharing information. And I love your tag line. Reminds me of one a builder I know uses: "I may be slow, but I'm expensive."

 

[idaho04]

I finally got to disassembling the cylinder. I got the gland nut wrench as you guys recommended, works great, and removed the retainer ring inside. Now I can not remove the gland nut. Any tricks to use to remove it, or do I just use a brute force? I do not want to mess up the piston.

 

[tommu56]

idaho04
at work we have air cylinders that have the side grove in cylinder.

were you able to spin the the end of the cylinder?

If so spin it again slowly and look in the slot on side of cylinder there might be a wire type lock ring in there.
Spin it slowly and look for a gap in ring if you find it then pry out one end of wire out gently and spin rod end of cylinder and it might spiral out, some times you might have to pull on wire with a pair of vice grips as you are spinning it.

tom

 

[idaho04]

The cylinder end would not spin but I can spin the gland nut. The nut moved out a little just so the ring groove in the slit disapeared towards the end but I can not grasp the nut, it is not out enough. The nut seems to be made out of aluminum or something soft, it gets scored easy when I try to grasp it with wide pliers. The gland nut has no handle to grab so I do not know if I can just pull the rod out with force (what force). I will see if there is a groove inside the cylinder end.

 

[dfkrug]

IDAHO:

You have one kind of cylinder I have not taken apart, tho I have
seen them on an SMC loader. Post another photo when you get it
out.

When you do, your piston nut will be torqued on with about a
million ft-lbs. I have found the best way to get them off (if you
do not have a 3/4-drive impact tool) is putting a rod thru the
other end and parking a heavy vehicle on it. Then use a socket
wrench with cheater bar.

The other glands I have removed use:
> tie rods (as shown by Ted)
> face-hole gland nuts, as mentioned
> circumferential-hole gland nuts, on some after-mkt cyls I got from
Surplus Center
> inside snap rings (JD loader)

 

[idaho04]

OK, guys, I got the cylinder apart. There was nothing special about it. I went to a pro shop and asked. They told me to knock it out using a hammer. So I did and the piston pulled the top out. I undone the piston nut and removed all the seals. There are eight of them on the piston and the gland nut. Now I do not know how to order the new seals. There is a rebuild kit mentioned in the Bradco manual but I can not find even the model on the net. So I am looking through the H/D catalog and can not make sense of it. I am not sure how to measure the seals and O-rings when the are worn out or damaged while removing. I guess I need a lot of help.

Help, help, help!