Thread: Hydraulic Cylinder Fix

I'm trying to sort out a leak in the lift cylinder from an old cherry picker (a 1973 Afron 450 made in Israel).
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From what I can tell, it's a single-acting cylinder with just one seal in the gland.
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The rod has the odd rust spot, and some dings which I cannot work out the cause of.
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The rod is 60mm, so metric - am I best off trying a local hydraulics supplier for a new rod seal and wiper, or should I be chasing parts from the manufacturer?

Also, is there anything that can be done for the rod?

I would make a new rod. Have a look around for chrome bar in canberra, here is a link to the material you likely need Chrome Bar - voestalpine HPM (Australia) Pty Ltd - voestalpine HPM (Australia) Pty Ltd
Or if you wanted you could maybe get away with de-chroming your rod, then re chrome it and have it ground to size, make sure it is straight first.
Personally i think it is alot less mucking around to just make a new rod if you can get the right size material.
If you know the size of your seals you might get them off ebay otherwise a hydrualics supplier would get them for you.

cheers, shed

If its single acting and it`s weeping oil out the top seal, then the main seal is leaking as well.
Do you have a photo of the main piston.
If oil is getting out, other stuff can get in. How does the cylinder bore look?

As far as repairing goes, having a new one made is the best option and probably the cheapest.
Hopefully the marks and rust are not to deep and you can go the grind, re-chrome and re-grind method.
Having it ground, metal sprayed and re-ground is another.

There is another way. It involves sanding, emery paper, time and your finger nail. I don`t recommend this method were peoples health (up a cherry picker) is involved.

Tony

Not sure what you need to do about the rod but the seals should be a generic metric seal. You should be able to find a replacement either on-line or at a local hydraulics place.

Simon

I remember looking at scissor lift work platforms for a previous employer as we used them quite often before finding out that regulations required almost a complete rebuild every 10 years. This being an elevated work platform too, it could well be similar. I would be talking to a local hydraulics place who make cylinders and getting their option. They may be able to repair for you or even supply a new cylinder for the purpose. Rebuilding for that application is not the sort of thing that I would want to take responsibility for myself.

The nicks in the rod are probably mechanical damage where the platform has been swung round into something. Suggests the rod could be bent too, so the plate and regrind option may not work.

Michael

The plating process leaves around .05mm of chrome on the bar, those dints are way deeper than that. If you were to regrind and straighten the rod, the finished diameter is going to be well below what will be acceptible for the rod seal to function. The rod is RS, recycle it into something else and buy a new one. It would be substantially cheaper to do so anyway, the only reason youd go with replating is if the bar in question was huge or had a great deal of machining done to it.

That's a displacement ram no piston or piston seal and the bore of the cylinder is not important there is a wear ring at the bottom of the rod to keep the rod in the centre of the cylinder .One problem I see in the pic is that it was painted & the paint was over the wiper seal .Don't do that after the repair .a flake of paint can break off the wiper seal & work its way down when the ram is retracting and get stuck in the gland seal that will cause a good leak & may of been your main problem. Are marks in the rod on the working area of the ram? They don't look that bad I have seen a lot worse that didn't leak a rub on the high spots with a diamond hone & polish with some emery .But that rod is an easy one to make no eye to weld on & no piston thread to worry about .Get some 60mm Chrome rod there are two types one has an Induction hardened skin the other doesn't .You only need the hardened one for Excavates ETC where the ram can get hit with rocks & dint .Get a new gland & wiper seal from someone like AB seals or a local to you supplier .

THESE blokes are good Rusty, a couple of hours from you.

John

RustyArc
Those Afron machines are very common in the Avacoado orchards, I had three of them in our farms. If you contact machinery suppliers in any Avodacdo growing area I am sure they will be able to give you the local hydraulic repairer phone number and you should be able to have yours repaired or replaced or maybe pick up a second hand cyclinder. The biggest problem with the Afrons is the hydralic pump that is burried in the bottom of the oil tank. I agree with stevew66 that the paint around the top of the seal could well be your problem. On our Afrons I fitted a close fitting guard on the outside of the cylinder to prevent sharp branches from piecing the seal. If the seal is damaged water can get in and then expensive problems will start.
Bob

By gosh I am amazed at the expertise and experience in this forum! Thanks for all the responses.

Fabricating a new rod is probably a little beyond my skill set and comfort level, but it's definitely an option to chase up as a longer-term fix.

As mentioned by Steve, there is no piston at the end of the rod, just a round steel disk that's screwed onto the bottom, and it looks like someone's maybe tried to unscrew it, and then cleaned up the mess with a grinder:
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The face of the gland is really beaten up, but there's nothing on the machine that'd hit it, so I'm mystified as to what caused it. That said, I'm suspecting this cylinder has been messed with in the past (I only got the machine in 2011, when it was already 38 years old).
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I've put a call into a bunch in Qld who claim to stock Afron parts, and I'm planning to go visit the local hydraulics guy to see what he thinks. The wiper and back-up ring look conventional (I think) but the seal looks a little odd.
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When I got the machine in 2011 I converted it to electric drive (brushless motors in the drive wheels, and a DC power pack for the hydraulic lift, all powered by 4 x 12V telephone exchange batteries).

Quick update - and thanks again for all the advice - I will follow up on much of it, but there was a need to get this machine back in service, so I'll see how it gets on.

So I found a better local hydraulics shop than the one I'd dealt with previously. He suggested cleaning up the dings pretty much as advised here, with a stone, and for the deeper rust spots, I used a wire wheel on a dremel, followed by a little sanding drum. I then went over the abraded areas with a buffing wheel and some polishing compound (all on the dremel).

I'm still mystified how all the dings on the rod and gland got there.

Still looks kind of awful, but hopefully less damaging to the seal, and I will be looking into either a new rod or entire cylinder as a longer term solution.
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The hydraulics guy sourced a new seal and wiper - he used a U-cup seal with an integral backing ring instead of what was there, and had to do some lathe work to get the new seal to fit, as well as cleaning up the face to fit the wiper as the beating it had taken was stopping the new wiper from being inserted.

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The machine is back together and not leaking any oil - I'll take some pics of the whole thing when I get a chance.

Glad it's back together AND not leaking oil. I bet you will forget about that cylinder and use the machine for many years without any problems.

Simon