About those 420 hydraulic cylinders...

General help and support for your Lindeman through 2010 John Deere crawler
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Bret4207
440 crawler
440 crawler
Posts: 169
Joined: Fri Apr 28, 2006 6:10 pm
Location: St Lawrence Valley NY

About those 420 hydraulic cylinders...

Post by Bret4207 » Wed Dec 19, 2018 12:25 pm

So I got out and picked up my cylinders from the big time industrial hydraulic place. Nice guys, no charge for tearing them apart and evaluating the cylinders. Took a look at them this AM. The guy said they were badly pitted and scored, not worth messing with. I have no clue what he's talking about! I'm looking at them and the bore of the barrels are stained, but I see no gouges, pits or scoring at all. The piston "arm" (not sure what the proper term for the part whut moves is) has a tiny dent and a small scratch or 2 on one and the other is better. Yes, they have some staining, but no pits or gouges. I think probably for an industrial application with high pressure hydraulics or on a big excavator or something they'd be useless, but IMO they look like they just need new seals and packings/glands/whatever they're called. The O-rings were definitely torn and the packing/glands, which appeared to be leather (???), was very stiff and worn and obviously they leaked and were letting oil by.

So where would I start looking for the stuff I need? I haven't gotten into the parts books yet and started running numbers. Does JD still carry any of this stuff or will the old numbers cross to more modern aftermarket items? The orings shouldn't be an issue. The leathers/packing/glands I'm not so sure on, but I don't even know the proper names or where to start.
40C, 420C, 1010C-L-BH, Cat D4

Jim B
350 crawler
350 crawler
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Joined: Sun Nov 05, 2017 11:36 am
Location: western Maine

Re: About those 420 hydraulic cylinders...

Post by Jim B » Wed Dec 19, 2018 1:37 pm

From past posts on here I would bet if you give Lavoy a phone call, or email him, he has everything you need. See what he suggests doing to them besides the new seals and cups.

I always just matched the parts in mine up at a local hydraulic shop. I guess we're lucky around here as these guys are used to ag and woods operations with old equipment and will spend time to match things up for us. If for some reason Lavoy can help let me know and I think I have the info of what I bought filed away.

I gently use a fine hand stone on dings on rods, if they need to be smoothed, not a file. I was using 240 to 320 grit emery cloth on the old rods with rust pits to smooth them when I replaced the rod seal O-rings, just a light dressing. I never honed the barrels and the cups seated ok. A honing might have improved them a bit but they were smooth so didn't do it.

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Bret4207
440 crawler
440 crawler
Posts: 169
Joined: Fri Apr 28, 2006 6:10 pm
Location: St Lawrence Valley NY

Re: About those 420 hydraulic cylinders...

Post by Bret4207 » Wed Dec 19, 2018 1:59 pm

Thanks Jim! My JD Ag dealer got me to my local JD industrial dealer and they can get the seal/gasket/cup kit for $116 and change each side. Seems a little steep, but it IS available. Had to track down the right catalog (62 blade) to find the hyd cyl diagram.
40C, 420C, 1010C-L-BH, Cat D4

Jim B
350 crawler
350 crawler
Posts: 2080
Joined: Sun Nov 05, 2017 11:36 am
Location: western Maine

Re: About those 420 hydraulic cylinders...

Post by Jim B » Wed Dec 19, 2018 3:20 pm

Do yourself a favor and next time talk to Lavoy, you can probably get seals for both for about that or less. It has been a few years but the last time I got them at the shop I use, it was about $50 for enough to do both sides.

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Bret4207
440 crawler
440 crawler
Posts: 169
Joined: Fri Apr 28, 2006 6:10 pm
Location: St Lawrence Valley NY

Re: About those 420 hydraulic cylinders...

Post by Bret4207 » Thu Dec 20, 2018 8:25 am

Yup, I gotta talk to Lavoy.
40C, 420C, 1010C-L-BH, Cat D4

Ray III
2010 crawler
2010 crawler
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Joined: Sat Aug 25, 2007 1:39 pm
Location: Troy, NY

Re: About those 420 hydraulic cylinders...

Post by Ray III » Sun Dec 23, 2018 7:38 am

Agreed, there is a big difference between sealing at 900 psi vs. 2500+. You should be fine if things are reasonably smooth.

If the dents and scratches are deep enough to leak oil you could try filling with JB Weld after drying with brake cleaner. The important thing is that there are no edges on the rod to cut or catch the O ring.

The piston seals can be started into the cylinder by cutting the bottom off a cottage cheese tub and cutting it down the side so it can be inserted into the end of the cylinder like a funnel.

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