Help with Hydraulic Cylinder Repairs

[philgreen]

New to the forum, this place is great!

I have a JD 855 with a 70A loader. The loader is tired with all the cylinders leaking at various rates. The guy I bought it from had two seal kits for the bucket cylinders, so I jumped in and rebuilt them.

The first cylinder came apart OK, but there was a small burr on it where the snap ring keeps the ram in the cylinder. Not knowing much, I just rebuilt it and carefully pushed it all back together. Big surprise, it started leaking a week later.

So, I took the other cylinder over to a hydraulic repair shop. They took it apart and cleaned away the burr. I also carefully cleaned up the piston that had a bit of a burr on it too. Put it back together and really big surprise, it started leaking about a week later. WTF!!!

Can anybody offer any advice. Seems I might have to redo everything and am not willing to throw good money after bad. I am running low viscosity hydraulic oil from JD. Please help.

Thanks,
Phil

 

[deereboy72]

Northern tool sells Hydraulic cylinders and hoses

Hydraulics | Northern Tool + Equipment

 

[J_J]

philgreen,

Were those the correct kits? Did the repair shop install the kit? Just take it apart and see if you did anything wrong, and again check for burs.

Some of the parts have to go on correctly. The lip on the seals for instance.

 

[Danno1]

Some of the parts have to go on correctly. The lip on the seals for instance.

...........and they want to be wet w hydraulic fluid bef you install them.


.

 

[philgreen]

Thanks for the replys,

Yes, I wet them down with hydraulic oil prior to assembly and I used the correct parts from the correct kit, per the instructions. The JD instructions were pretty good, with pictures and drawings to make sure things go together the right way and with the right parts.

I know why the first cylinder leaked, I didn't do a good job. What has me stumped is why the second cylinder is leaking? JJ is right, I will have to take them down for a look see. Before I do, I hope somebody else on the forum has been in a similar situation and posts a reply.

P

 

[Wayne County Hose]

Those JD cylinder bores can be a real bear to get to seal. Check the o-rings when you disassemble it. Tther should be two of them, a round one and a rectangular one. The round one goes towards the fluid. The other one is a back-up and goes away from the fluid. Check the back-up, one side will be curved, the curve goes towards the o-ring. You also might have torn the o-ring when you installed it. Good luck.
Andy

 

[J_J]

Phil,

Did you use it very much after you installed the new set of o-rings. It just might need a little time, to setup and for the o-rings to flex/expand, etc. Some rubber/seals expand in some types of fluid. Is the leak a drop or two, or a stream?

 

[philgreen]

Andy,

I'm pretty sure we installed the rings in the correct order. I had no idea however, that there was a concave orientation to the backup seal. I will check it. One question, if I tear it apart shouldn't I put in all new seals in any case???

JJ,

Very good point. I have not used it to any great degree. I am seeing a couple of drips from both cylinders. (Just enough to piss me off!) I will wait a few weeks to see if it clears up.

I wondered if using low viscosity oil might be giving me trouble? Any comments??

Thanks,
Phil

 

[J_J]

Phil,

Did you have to clean up any burs, rust, etc? If you have to smooth off some things. Do not sand /rub up and down the cyl rod, you will leave scratches that may run past the seale/o-rings.. Sand around the cylinder rod. If the repair is longer that the seal area, you will probably have trouble later on. A drip here and there. Another thing, is it leaking at rest or when in operation/ full pressure.

http://www.maxxhyd.com/hydraulicseals.htm

 

[Wayne County Hose]

I have seen units develop leaks when switching over to a lower viscosity oil, but these cylinders should seal up regardless. The o-rings should not leak and time won't make them leak less.
I would install new o-rings but the other seals should be fine. The bores may need to be honed. Inspect where the o-rings ride very carefully for anything.

 

[philgreen]

I'm renewing my old thread because one of the cylinders I repaired earlier blew out it's snap ring and now I'm stuck.

I took the cylinder in to a shop for repair. They say the groove that the snap ring sat in has worn away and needs to be rebuilt,.... $400.00!!! After coming too from my feinting spell,.... they said they are not having good luck finding a one for one replacement. I looked at Prince cylinders and they have one that seems to be the correct size, but now I have no idea if it will work, based on what the repair shop said.

A new cylinder from the good folks at JD,.....$530.00!!!!

Does anyone have a 70A loader for parts, any cylinders out there for sale? The JD part number is, AW28950 HYDRAULIC CYLINDER , BUCKET (ID = 44 MM (1-3/4")) (SUB FOR AM106177 OR AM118275),

Any help would be appreciated,

Phil

 

[Rollcenter]

I sell hydraulic equipment for a living, we manufacture and repair mining equipment. If you could give me the specs of the cylinder, I can tell you approx what a "QUALITY" repair should cost from your hydraulic repair shop.

I will state, HIGH QUALITY machine work is not cheap....

 

[philgreen]

Hi Rollcenter,

The cylinder has a 24" stroke, the ID of it is 1 3/4", the operating pressure is 2150 psi.

Here is what I know about the problem;
The snap ring sits in a groove that is machined into the cylinder. I spoke to a local cylinder rebuilder who told me that this is a piss poor design for a hydraulic FEL. This is due to the repeated back and forth stress on that snap ring and it's groove, in addition the weight you lift puts a great deal of non-linear wear on the cylinders. Over time the groove degrades and allows the snap ring to slip free. The repair would be to add steel to the ID and remachine another groove into it.

I assume you know a great deal more about this and you may have some other ideas about how you might fix it. I only told you this to give you some background.

Hope it helps, and thanks in advance for your assistance.

Phil

 

[Rollcenter]

The hydraulic shop is right, the packing gland being held in by a snap ring is not much of a setup.

If I were you, I would check here for a replacement cyl, a replacement new cyl would probably cost less than a QUALITY repair.

Bailey Hydraulic Cylinders Manufacturer

 

[philgreen]

Thanks very much for your help. I will try these guys.

I have an appt with another local repair guy tomorrow. He is a friend of a friend and I wanted to know if he can add any new insights on the situation.

Phil

 

[Lunker]

Just a thought - check Surplus Center and Baileys Standard Hydraulic Cylinders for what they may have that is close to what you need?

No clue if this would work but it seems close to your measurement:
https://www.surpluscenter.com/item.asp?item=9-7158&catname=hydraulic

-Nick

 

[kebo]

Not to sidetrack the thread, but are the cylinders on the Model 70 loader the same as on the 70A?? Seems like they probably would be. I have a cylinder that has a pretty slow leak on it, but not so bad that I feel it needs to be repaired just yet. Just wondering if I might run into the same situation as the OP???

 

[wdchyd]

Philgreen,

Just a note to show you a similar situation that a customer ran into recently.....This one from an older Hough Payloader....

The first photo was from a cyl that was repacked over & over & over & over (well you get the point).......it needed some TLC at the gland like yours.....

Once machinined/welded/remachined and honed, the seal/groove area was ready for repack with another fresh set of seals.....

Like Rollcenter said "HIGH QUALITY work is not cheap".......unfortunately some of my best work gets hidden inside the equipment I'm working on and sticker shock does happen when repairing worn out/rusted equipment...

Hopefully your other local repair guy is a good welder and machinist.....

 

[wdchyd]

Here's the same cyl barrel.....

 

[philgreen]

I stopped by the other hydraulic repair guy today. He thought the best way to make a repair to the cylinder would be to cut off the actual cylinder barrel with the bad groove and weld in a new one. He estimated about $300 in materials alone, adding in labor makes this route as pricey as my other hydraulic estimate.

He is going to see if anything is close on the replacement market. I looked at Bailey's and they have a couple that might work.

Kebo,

The 70 loader goes on the 650/755 tractors series, the 70A is for the 855/955. The reason for this is because the frame size on 855/955 is larger than the 650/755. Having said that I checked the part numbers on the JD website, and the do used the same cylinders.

Lunker,

Thanks I will check it out.

wdchyd,

Thanks for the great info, I agree with your thoughts on quality and price. It looks like you do great work.

Phil