Question about Bush Hog Backhoe and removing ram from cyclinder for rebuild

copotay · Dec 10, 2015

Hello all, my first post, hope I am in the right place. I have one of the cylinders leaking extremely bad on my Bush Hog Backhoe model 662H. Its one of the first older models I think they made I'm guessing in the 80s. I have looked at several posts and searched for the exact kind I have but even on the new models the cylinder looks to be made a bit different. I have ordered the seal kit for it and was wondering if anyone had experience with this type of cylinder. The Gland is loose and easy to remove. My question comes in, after unscrewing the Gland, if I can then just pull out the entire assembly or is there something else I need to make sure to undo like a snap ring inside the housing or something like that. I will post a picture of the cylinder and its leak. tks for any help someone can give.

davesl708 · Dec 10, 2015

Hi. Welcome. We like pics.

The piston should come right out the front. Go easy reassembling so as not to damage the orings and seals.

copotay · Dec 10, 2015

Tks very much for the information appreciate it greatly, thought the pictures would help out too with so many variations of cylinders.

Texasmark · Dec 13, 2015

I don't know what a "gland" is but I assume you are talking about that disc with 2 holes encircling the shaft in pic #2. I agree on unscrewing it and the whole shebang comes out. First thing to do is to remove the hyd line from the rear of the cylinder too prevent a vacuum buildup when you pull the ram and have a means to capture it when it comes out so that you don't scar the shaft.

You should have a pair of seals on the "gland", probably a pair of O rings, one to seal the gland to the cylinder housing and the second to seal around the ram shaft.

I bought a JD 95 combine once that was well worn out. Decided to repair all the hydraulic cylinders. Kid you not, I think JD used every type of cylinder assembly available at the time. Other than in pairs for a specific function, there were no two cylinders that dismantled the same. The real tricky one was the one with the hidden snap ring that you had to push the cap (that the shaft goes through on top of the cylinder) in slightly to get it exposed to get at it. Not hard to find this type as there was no visible way externally to see how the thing came apart.

On installation, I usually soaked everything real good in hyd fluid. On the cylinders I rebuilt on the JD 4010 loader, I had to use a comealong to get the ram out and back in. Tough job working alone on those rather large cylinders.

Good luck.

copotay · Dec 13, 2015

Tks Texasmark, yes that's what they call it a gland ring, just learned it's name by reading posts and looking at diagrams. That's why I asked about wether it would just slide out, I read some posts about hidden snap rings inside and could only imagine me trying to slide it out with a ring still in place. I looked at the blow up diagram of the cylinder that only shows a bunch of the gaskets and such but saw no snap ring in the diagram, but as you said you can never tell what a manufacturer will do. Thanks very much for the tips to get it out too.

Here is a link to the blow up diagram and the descriptions of each part below the diagram

https://store.germanbliss.com/bush-hog-662h-backhoe-lift-and-crowd-hydraulic-cylinder-50017727-parts

Texasmark · Dec 13, 2015

copotay said:
Tks Texasmark, yes that's what they call it a gland ring, just learned it's name by reading posts and looking at diagrams. That's why I asked about wether it would just slide out, I read some posts about hidden snap rings inside and could only imagine me trying to slide it out with a ring still in place. I looked at the blow up diagram of the cylinder that only shows a bunch of the gaskets and such but saw no snap ring in the diagram, but as you said you can never tell what a manufacturer will do. Thanks very much for the tips to get it out too.

Here is a link to the blow up diagram and the descriptions of each part below the diagram

https://store.germanbliss.com/bush-hog-662h-backhoe-lift-and-crowd-hydraulic-cylinder-50017727-parts

Yes it's threaded....look at the opening end on the cylinder. That's an easy one. All you need is a good penetrating oil and a good set of large needle nose pliers bent on the end at a 90 degree angle (I have a pair) or make your own wrench, or a punch and a hammer back and forth punching at both holes at the lowest possible angle. All the stuff on the left is at the top and the stuff to the right is at the bottom. Don't know what you know about packing but packing is a seal of some sort and in these things it can take several forms. The top part is possibly an assembly that comes out when you pull the gland nut. But I'd bet it's not and the cylinder is counter bored and Item 30 probably rests against item 14 which rests against the diameter change in the cylinder and the O ring, Item 9, is probably mounted in a groove in Item 30. The gland nut jams all this stuff in place and on the up stroke the bottom part of the ram hits this top assembly of parts and that's what stops it's extending action.

When you pull the rod, with the gland nut out, all this top stuff will come riding on top of the stuff on the right of the breakdown. You will need to replace the wear items then be sure and load the top stuff on the shaft before you put the bottom on and torque the nut. Since the diameters will be different, as you push the rod back in, the top will stop at the counter bore shoulder and the bottom and the shaft will continue to the bottom.

I have had some I couldn't get apart so I used compressed air in the fluid connection at the bottom end to "blow" it out. Just remember the force will be the PSI of your compressed air X the area (½ diameter squared x 3.14). If you have a 5" cylinder with 100 psi you will be looking right at 2000# of force. Gotta use high pressure to do the job, but little squirts and watch the cylinder...just nudge it along and have a place for it to land.

Going to bet you that bush hog sells a kit for that job. Makes it a lot easier and missing a part is pretty much eliminated.

copotay · Dec 14, 2015

Tks for that heads up on the different diameters and the compressed air tip. Yes they have the seal kit I ordered from local tractor place it's 85 bucks and listed before #1 in the list below the diagram. I also watched a couple of generic youtube videos that the outer seals must face in a specific direction for it to work right, don't have the seals yet but supposedly one side of the outer seals will likely be flared out more than the other. Btw in a side note these machines use regular 10-w40 engine oil instead of hydraulic fluid, thought that was strange but I have the manual which says to use it along with confirming that with the local dealer. Also bought a gland ring wrench for 21 on Amazon since I have several cylinders with tiny leaks, not near as bad as this cylinder, but figured I will eventually be re packing those too.

https://www.amazon.com/dp/B00A8FNPYU/ref=cm_sw_r_awd_wbRBwb64AZAZM

Texasmark · Dec 14, 2015

Like any seal of the type, the flare is designed to seat with applied pressure so the seal has to go in such that fluid pressure from the inside will force the seal against the shaft or cylinder wall as the case may be for the inner shaft seals and outer cylinder seals. Just pay attention as to how you disassemble it and you should be good to go.

copotay · Dec 14, 2015

Great tks very much

wdchyd · Dec 16, 2015

Lots of good info here with the exception of using compressed air to blow apart cylinders......sorry but somebody is gonna get hurt

If you have a stuck rod assy use a come-along or sledge with a junk shaft in crosshead, or power it out with hyd oil (messy).....sometimes the blue-wrench is necessary