JD Hydraulic Cylinder Rebuild Help?

reasley · May 24, 2008

Good evening,

I have a JD 4300 and need to rebuild the front end loader cylinders. I have the factory workshop manual for the tractor, but it doesn't have the instructions for the loader and its cylinders. I also have four seal kits.

All I need is to know how to remove the rod from the cylinder. I have attached the parts picture of the cylinder and have removed the external circlip. It doesn't look like anything is holding it in, but I can assure you that it is!

Does anyone have experience with these and can point me in the right direction?

Thanks in advance!

Richard

Wayne County Hose · May 24, 2008

Good evening Richard,

#3 looks like a snap ring. Remove it. (I guess you already did.) Lock the cylinder in a vise. Make sure the cylinder is empty of oil. In the vise, point the ports down with a way to catch any oil still in the cylinder. Now, push the rod in. Then, with a slide hammer like action, pull the rod out quickly. You want the piston to hit the gland and knock it out of the housing. Sometimes, they just won't come out. This is when I'll point the rod in a direction so as not to hurt anything. Then, I have a 3/8" ball valve with an air chuck on one end and a #6 JIC female on the other. I attach it to the base end port of the cylinder and open her up. If that still doesn't work, time to chain the base of the cylinder housing to something unmovable, then chain the rod to your drawbar. Let the machine do the work. This last resort had NEVER failed.

Hint, sometimes tapping the gland with a brass punch (#10) then squirting some penetrating oil around the outside of the gland helps. Also, if the slide hammer action won't work, tap the gland in and look for another snap ring. I'm looking at #6 and not really sure what it's function is, but it may be another snap ring.

Hope this helps, Andy.

kennyd · May 24, 2008

Here is what I learned when I did mine and had the same problem:

In the seal kit there is a orange plastic piece...in the end of the cylinder there is a groove...Now put the plastic piece in the groove, make sure its flush all the around. Now you can do as Andy said...give it a good YANK!

What is happening is part #6 is expanding and catching in the groove stopping you from pulling out the rod. Drove me crazy also!

When you go to put the new seals on the piston, boil them in water for a while to soften them up. I then wrapped a piece of thin aluminum flashing around the piston and clamped it with a hose clamp while they cooled-but this was probably unnecessary.

Let me know if this helps...

reasley · May 25, 2008

Thanks for the replies, Andy and Kenny --

I posted the message right before the family left for the new Indiana Jones movie so I had some time to think about it there. When I took the cylinder off today, it was very hot (outside, not the cylinder) and I had about 20,000 things to do today, so I wasn't really thinking about it. Tonight, I realized that there must be 2 points of resistance: the outside snap ring that I had already removed only prohibits the rod guide from being "sucked into the cylinder" under pressure and does note keep the rod guide from "popping out" under the other direction of pressure -- that part must be the one that I"m missing, right? Kenny, is that what you are referencing when you say "In the seal kit there is a orange plastic piece...in the end of the cylinder there is a groove...Now put the plastic piece in the groove, make sure its flush all the around. Now you can do as Andy said...give it a good YANK!" So, if I'm understanding you correctly, the orange "split ring" that I also saw in my kit is merely a tool to remove the rod assembly, right? So, to use it, I will plunge the rod guide down into the cylinder, put the orange split ring in the groove of the body, and then remove the rod guide and rod assembly, correct?

Thanks in advance!

Richard

kennyd · May 25, 2008

Yes Richard, that's it... the split plastic piece is a tool, it fills the groove so that ring (#6) can slide on out of the cylinder body.

reasley · May 25, 2008

kennyd said:
Yes Richard, that's it... the split plastic piece is a tool, it fills the groove

Logged in as reasley
Title:Re: JD Hydraulic Cylinder Rebuild Help?

Message:

so that ring (#6) can slide on out of the cylinder body.

Worked like a charm, Kenny -- thanks! Now, I have another problem. When I disassembled all of the seals, guess what? -- the seal kits from John Deere are the wrong ones. My loader number is 013546 and if you look it up in the on-line catalog (search on 420 loader), it lists 10 or so lift cylinders and 10 or so bucket serials -- spec'd by serial number of the loader. Looking at the #10 bucket cylinder, this is the kit that they gave me at the dealership. I had originally looked up #18 bucket cylinder (look at the ordering of cylinders and you'll see why I chose that one). But I didn't order the kits from #18, I let the parts guys look them up, figuring that they would have more accurate data and would be more certain of the right kits. So, when I realized a while ago that the kits are not the right ones, I concluded that #10 must not be the right cylinder and #18 must be. So, I copied down the part number on the cylinders that I have (it is AH166856) to try to match it to the right listing on-line. When I did, I found that it matches the #10 cylinder -- precisely the one that the dealership looked up. But -- the seals are not right! So, looking more closely in #10's part list, there is a previous seal kit (AH167205), but in the notes, it is superceded by the one that they gave me. So -- I guess that the solution to the problem is take one of my cylinders down on Tuesday and go from there? Also, the lift cylinders are listed as using the same kit, so I guess that I need to go ahead and pull one of those in case these kits work on them.

Any additional suggestions appreciated!

kennyd · May 25, 2008

HHHMMMMM

This is what I came up with:

First, I only see two different cylinders for the 420 loader listed this way:

Cylinder, Lift(420) (S.N. -013054)
Cylinder, Lift(420) (S.N. 013055-)

Then:
Cylinder, Bucket(420) (S.N. -013054)
Cylinder, Bucket(420) (S.N. 013055-)

Based on your serial # (013546) you would select the second one (because your serial # is after 013055.

From that, you would want part #16:
16 AH176273 HYDRAULIC CYLINDER KIT

I am not sure where you guys are getting the other part #s?

So again, my best guess is AH176273.

Kenny

I will PM you my phone # in case you want to call me about it...

reasley · May 26, 2008

kennyd said:
Based on your serial # (013546) you would select the second one (because your serial # is after 013055.

From that, you would want part #16:
16 AH176273 HYDRAULIC CYLINDER KIT

I am not sure where you guys are getting the other part #s?

So again, my best guess is AH176273.

Kenny

Good evening, Kenny --

I transposed the serial number but the result is the same, I think. My number is 015346, not 013546 but again, I think the results are the same.

Your numbers above are the same numbers for the kits that I got -- but they are wrong. Weird. Also, I confirmed the kits by matching my cylinder numbers with that particular parts listing -- one and the same. The only thing that I can figure is that JD must have a parts number mistake that is seen both in the consumer parts list and the one that the dealer sees.

I have cleaned my old seals and have them packaged and will try to match them at the dealer tomorrow with any kits that they might have on the shelf. Also, I could probably match them up now at the local hydraulic shop, I guess . . .

Richard

reasley · May 26, 2008

Wayne County Hose said:
. . . Hope this helps, Andy.

Good evening, Andy --

I note that you are in the business.

Prior to this rebuild, I have never been inside a hydraulic cylinder before but I have an extensive mechanical background.

I have looked at my cylinders and parts while waiting to get the right kits (see previous thread messagees) but, even though I have mechanical experience, I could benefit from your experience, if you are willing. Assuming that's the case (and also assuming that this material hasn't been covered already in a previous thread -- if so, kindly redirect), I have a couple of questions:

1. Is there a tolerable level of scoring on the piston? Or, is it a "scored at all, then check the bore, if scored at all, scrap" type thing?

2. I am sure that out of round on these cylinders is not an "eye it" type of thing -- I have a machine shop that can check it for me, if needed. However, going back to Q. 1 -- if there is any scoring evident, is this indicative of either a permanent or momentary bending of the cylinder rod?

Many thanks in advance.

Richard

kennyd · May 26, 2008

Richard, is it possible that they are not "wrong" but "different"? Have you tried to install them?

There are updates in parts all the time...Maybe you have the latest and greatest.