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View Full Version : On site fix for pitted hydraulic cylinder rods or shafts pitted where seals run



Volvomad
02-23-2012, 09:32 AM
Does anyone know an easy fix for this. I think chemical metal is to thick to get deep into pitting and would require alot of sanding. An extra hard paint primer or fiberglass resin might be up to the job. Does any one have any ideas, prefferably in an aerosol can?

pointrow
02-23-2012, 09:50 AM
Real fine emery cloth, clean with brake cleaner then use crazy glue. Hit again with emery cloth.

StanRAUUS
02-23-2012, 11:00 AM
Better patch materials http://www.belzona.com/prod1k.aspx

tregurtha
02-23-2012, 03:48 PM
belzona is great i used to use it to rebuild pump bodies and machine back to std A1

JeremiahSr
02-23-2012, 05:12 PM
Just remember that anything that comes loose while rod is in cylinder is now in your hydraulic system. Take extra care in the prep work to assure good attatchment. A hard epoxy coult get in there and do extensive damage to the control valve or pump. These kinds of patches to save down time and money could very well cost you more down time and more money. JMHO

cps
02-23-2012, 05:58 PM
DONT USE ANY THING ON YOUR CHROME RODS, never seen any thing like this work, if the pits are not to deep rub of any sharp spots with very fine emery cloth, reseal and hope for the best! Might get you another while out of it, but in the long run it will be cheaper to replace the chrome rod!

What machine is it on?

Aiden

Volvomad
02-23-2012, 08:15 PM
Thanks for the replies . It applies to a whole dose of auld crocks, diggers, loaders,dumpers and agricultural tractors and emplements. But it immediatly applies to the input shaft of a hydraulic pump off a Deere tractor that is pitted where it runs in the two seals.

Nige
02-24-2012, 06:08 AM
Thanks for the replies . It applies to a whole dose of auld crocks, diggers, loaders,dumpers and agricultural tractors and emplements. But it immediatly applies to the input shaft of a hydraulic pump off a Deere tractor that is pitted where it runs in the two seals.So in actual fact it's not for a hydraulic cylinder but a rotating shaft of a pump - a totally different animal. Not having seen the shaft in question it's hard to comment but I would be extremely surprised if it was chromed. A shaft like that is probably case-hardened in which case metal-spraying would be probably the suitable repair procedure.

I appreciate that you can't throw tons of money at a "dose of auld crocks" and fix things exactly 100% but IMO by starting off thinking the way you are is going to land you in deep doo-doo before very long, unless of course the owner/s are only interested in short-term fixes. If they are, and it's been posted many times in this forum, make sure that it's pointed out to them that this is not the correct fix, that you're doing it only on their instructions, and you're absolved of any & all responsibility if things go South.

As stated by others above it's not recommended to use anything like Belzona, resin, or anything else in an attempt to fill holes in the plating on a cylinder rod for the simple reason, again as posted above, that if any or all of it breaks loose while that part of the rod is inside the cylinder the foreign material is then floating around the system. Big no-no. The rod can be polished using a flap wheel or something like it (remember the chrome is hard) and fit new seals but all this will do is put off the inevitable seal failure for a while.

If you have a chrome plating shop close handy that has the capability of doing hard chrome plating (as opposed to decorative) most cylinder rods can be selectively plated to repair small areas where the plating has been damaged. However if there are a large amount of pits on a rod then the more economical option is to remove all the original chrome and re-do it.

OzDozer
02-24-2012, 06:28 AM
There's not much apart from replacement to fix bad pitting in rods. You could try some low-temperature silver solder in the worst pits, then file the solder smooth with a flat file, and finish off with emery cloth tape.

Nige
02-24-2012, 07:29 AM
There's not much apart from replacement to fix bad pitting in rods. I disagree. The cost of replating a rod, provided it's straight to start with and otherwise undamaged, is a fraction of the cost of a new rod. That's how the manufacturers recondition the majority of their service-exchange rods. The trick is finding someone competent to do the plating that's not too far away from your location.

OzDozer
02-24-2012, 08:40 AM
Nige - Here in little ole West Oz, the chrome platers are nearly all gone, and there's only 3 hard-chrome platers in a city of over 1.8M people.
These 3 hard-chrome people all drive Cadillacs & Rolls Royces, and they make anyone who wants a rod re-chromed think they're getting gold-plating, not chrome plating.

I've been trying to get a decent deal on rechroming a lift ram shaft on a Nissan 2.5T forklift. The shaft is about 5' 6" long and 3" in diameter. The quoted prices ranged from just under AU$1,000 to AU$1,500.
The cheapest quoter couldn't start on the job for 8 weeks, the dearest quoter could start in maybe 3-4 weeks. For that kind of money, you can buy a new length of chromed shafting, weld or machine new ends and still have many $$$ to burn.
I have never seen anyone here in recent years, re-chrome any shaft or rod, unless it was an un-obtainable dimension, or it contained a fancy lot of machined ends or collars that were big money to remove/manufacture.

Re-chroming nowadays is a very expensive deal, and many re-chromers are being shut down because of the cost of dealing with re-chroming toxic waste, or the regulations associated with those industries.
It's so much easier and cheaper to grab a brand new section or chrome rod off the shelf, attach your ends or collars, and go straight back to work. It's been that way here for years, and it ain't going to turn back, anytime soon.

Diagonal Brace
02-24-2012, 11:20 AM
Depending on the size of the shaft involved is there possibly a speedi sleeve that may provide an adequate repair? They use them on crankshafts but I dont know if they make the size in question.

smittysrepair
02-24-2012, 10:46 PM
Nige - Here in little ole West Oz, the chrome platers are nearly all gone, and there's only 3 hard-chrome platers in a city of over 1.8M people.
These 3 hard-chrome people all drive Cadillacs & Rolls Royces, and they make anyone who wants a rod re-chromed think they're getting gold-plating, not chrome plating.

I've been trying to get a decent deal on rechroming a lift ram shaft on a Nissan 2.5T forklift. The shaft is about 5' 6" long and 3" in diameter. The quoted prices ranged from just under AU$1,000 to AU$1,500.
The cheapest quoter couldn't start on the job for 8 weeks, the dearest quoter could start in maybe 3-4 weeks. For that kind of money, you can buy a new length of chromed shafting, weld or machine new ends and still have many $$$ to burn.
I have never seen anyone here in recent years, re-chrome any shaft or rod, unless it was an un-obtainable dimension, or it contained a fancy lot of machined ends or collars that were big money to remove/manufacture.

Re-chroming nowadays is a very expensive deal, and many re-chromers are being shut down because of the cost of dealing with re-chroming toxic waste, or the regulations associated with those industries.
It's so much easier and cheaper to grab a brand new section or chrome rod off the shelf, attach your ends or collars, and go straight back to work. It's been that way here for years, and it ain't going to turn back, anytime soon.

That is no doubt true because of where you are. But here in the good old USA where I am, I can usually have a rod re-chromed for about half the price of replacing the rod and about 1/3 the price of a new one. Plus I can usually find a good shop to do it fairly quickly that is located relatively close by. So I guess it just depends on where you are but then again it never hurts to check and see what you can find. But none the less in my opinion I would not try the epoxy patch method on a cylinder rod. If the customer just will not fix it right I will smooth out the rough spots and install new seals. I have spent enough time reworking hyd systems that where damaged due to contamination and I would definitely not want to be the one causing the damage.

OzDozer
02-25-2012, 12:43 AM
There are epoxies out there that will perform better than any steel. There's more than JB Weld available. They aren't readily available in your corner store, they are stocked by specialists in the mining industries.
These epoxies are used inside trash and slurry pumps and other severe duty mining applications, where abrasion is horrendous. However, the cost of these epoxies generally makes Cat parts look like Wal-Mart specials.
The problem with trying to fix pitting in rods and shafts is that you need to prepare the surface in the pitted area so that the epoxy can bond to it satisfactorily. This is often impractical, because the pitting usually comprises lots of small holes.

A Speedi-Sleeve should work just fine on a rotating pump shaft - but hydraulic cylinders need a totally different approach.
You have to remember that deep pitting doesn't just let oil leak out, it allows dirt to be carried back into the hydraulic system, which creates rapid wear.
As a result, deep pitting is a big no-no that has to be addressed as a major issue, before it leads to severe wear within all the other hydraulic system components.

Nige
02-25-2012, 09:59 AM
I guess it depends on where you are in the world. In my past experience it's always been far cheaper to strip and re-chrome a rod than anything else, generally because chromed rod (or chromed hollow bar for the larger cylinders) is not readily available off the shelf. Additionally local regulations don't tend to be so demanding regarding the "elf & safety/environmental" side of things so chrome plating is still an economic propostion. One thing that surprises me is how slowly HVOF technology is taking off for hydraulic cylinder rod reconditioning. HVOF coating is much more durable than chrome.

Horses for courses I think, but it got us off on a tangent when it turned out the OP was not wanting to repair a cylinder rod but a rotating shaft. Speedi-sleeves (again not available everywhere, certainly not where I am) would be the first option. Failing that either metal spray or HVOF.

Randy88
02-25-2012, 08:38 PM
If its on a shaft, you'll almost have to tear it down to do anything anyhow, I'm guessing its on the outside of the housing, I've used speedy sleeves and got by fine, but they have a limited use. Not sure how much is considered too costly but if it were me, I'd opt to replace the shafts in question and rebuild the pump and be done with it, by the time the shafts worn enough, how good is the pump at that point anyhow.

leisureexpress
02-25-2012, 09:25 PM
I fixed the backhoe bucket curl cylinder on a JD310E that the owner severly gouged out on rocks. It roughed up an area about 2" tall and 1/4" wide. This was about 9 years ago and at the time I thought it was a temporary fix. What I did is tig welded in the area with stainless rod and blended it smooth with a bear-tex wheel. It is still in service today some 4000+ hours later. He had to replace the seals, to keep it from leaking right after the damage was done, but I'm surprised it is still fine.

Volvomad
02-26-2012, 05:23 PM
All the repairs I do are for our own machines. The family buisness is Plant and Agri contracting. The newest machine is a 2004 L90E with 16K onthe clock, after arriving in 2005 with only 2K. The oldest, a Case 1150B is alittle older than I am, I think. I spend most of my time in the shop but also drive when required. There are lots of leaky rams and shafts in the yard and the repair quality has to be related to the machines age,hours,projected future life span,time & cost of redoing a cheap repair and the cost of doing it right. I dont think there is a hard chrome shop in Ireland. I dont know anything about speedi sleeves [but they sound good]. The sleeve would have to be pretty thin because the drive splines are not much below shaft diameter. I have tried super glue ,I am just waiting for the seals, they got lost in transit ,very unlike Johndeere.The pump is not that hard to get at and the last set did 2.5K and the shaft was just as bad. The pump came off a scrap burned machine, hence the pitting. If any one has more info on easi sleeve suppliers or metal spraying(is there a kit available for this) please let me know.

OzDozer
02-26-2012, 07:57 PM
Google "metal spraying" or "plasma spraying" for more info on those processes. I've never had any real success with them. The problem with metal spraying is that the substrate has to be nearly molten, or in a plastic state, before the metal spray material bonds successfully. Most times, this doesn't happen, and the bond is not 100% successful. I've had some very expensive engine failures where metal-sprayed crankshafts failed when the metal spray material came off once the engine was put to serious work.
Google "speedi-sleeve" to find out more about these handy thin sleeves. They're available from nearly all bearing & seal suppliers, and they come in a multitude of dimensions. You do need to take great care with their installation.

RayF
02-27-2012, 08:23 AM
HVOF is taking off here. I believe Westrac use it on their rod rebuilds and another mob just up the road from me are doing it. There where some early disasters but its improving all the time.
Arc Spraying while not suitable for cylinder rods, is a good process for rebuilding shafts and bearing surfaces on axles. You can spray on whatever metal you want from white metal to stainless which makes it versatile. I get cast iron pistons sprayed out of old stationary engines with Aluminium Bronze.Works well.