The old 425 again…LOL

[2manyrocks]

I recall someone posting that rebuilding hydraulic systems requires cleanliness on the order of surgery room cleanliness. While I suspect that may be an overstatement, it does serve as a reminder of how much of a challenge it could be to rebuild the PT hydraulic system. I have found it a challenge to rebuild hydraulic cylinders which are far more simple than the type of work you might be facing.

 

[Modrob]

Dang…awful strong evidence that I’m in over my head. LOL…I think now there is so much to know about how these hydraulics work, that I’d have to spend a lot of time TRYING to learn about these hydraulic systems. I believe I’m oversimplifying it, and that, I can see, would get me in a lot of mess the deeper I’d tear into this…
Again, many thanks for the straight-shooting.

 

[ponytug]

Terry at Power-Trac told me "open heart surgery clean". From my experience, it is a good description of what is needed.

Larger hydraulic systems often treat the tank as "clean" with filtered returns, a filtered refill nozzle and filtered breather openings. That limits the damage from a single component failure, but in the case of a drive pump failure scenario, that would still probably trigger a cleaning of all the hoses downstream, and a rebuild of all of the drive motors, i.e. the whole circuit. For a PT with a single suction filter, that means rebuilding the whole hydraulic system. Basically, going over all of the machine with the view that every component is dirty until proven otherwise by cleaning and disassembly.

@Modrob I'm not saying that disassembling a component such as a motor or a cylinder wouldn't be educational, just that it might not result in a working component the first time. I'd try looking around YouTube for some rebuilding videos. Cutting Edge Engineering Australia has a number of good videos on cylinder repair and rebuilding. I think that generally his technique is pretty amazing, and tackling a problem with "How would Kurtis do it?" is a pretty good strategy, though my hand eye coordination isn't in his league, nor my mechanical or machining knowledge.

All the best,

Peter

 

[oldnslo]

Companies like Attica hydraulics in Michigan or ETS Hydro in Memphis reman units and then have them for sale. I believe they have a “core” charge to get the old housings back.

Typically a complete rotating group with new bearings and seals is approaching the cost of a new pump. Normally not advisable to put different piston in old cylinders block and might not be able to even purchase piston as a spare part.

I am not sure if Danfoss still builds the Eaton 15 series but suspect you might be able to find a similar size replacement but would also suspect ports location and possibly sizes would change.

Yes on cleanliness being critical when working on hydraulics especially with closed loop hydrostatic drive since dirt just runs in the loop damaging the pump and motor(s) in that loop.

Best of luck on your decision

 

[MossRoad]

In general, I am all for fixing up old equipment and getting them running, but for $3k-ish you could buy a dedicated dumper crawler with a 3,300lb capacity. E.g.

New 2025 IR IRD25 Crawler Dumper

New 2025 IR IRD25 Crawler Dumper Fuel Type Gasoline Additional Features 9" Rubber Tracks, Seat

bid.rollerauction.com

There are bigger ones available from Yanmar and others, and cheaper for direct import.

All the best,

Peter

Away with your temptations!!!!

 

[MossRoad]

While I know it's tempting to try and rebuild the old PT425, as others have mentioned, and I agree, it's going to be very hard to salvage any of the existing hydraulic components and being completely sure 100% that you got all of the debris out of them from the damaged tram pump. All those little metal pieces not only just go somewhere, they score and eat the walls of the pump cylinders, and if they get out of the tram circuit, they damage the motors.

Having them all torn down, inspected, certified as undamaged, and then rebuilt could be costly if sent out. Doing it yourself would require some knowledge.

Cleaning out every hose and fitting on a 20+ year old machine you might as well replace the hoses at that point, because they're probably getting old, brittle, worn, etc...

So price the cost of a new tram pump, two new PTO pumps, 4 wheel motors, all the hoses and fittings, the hydraulic cooler, the valves and bodies, the rams, and anything else I forgot...

If you're dead set on doing it for fun, inspect that tram pump. You said you found the pistons damaged. Look at the cylinder walls where those pistons travel. I'd be surprised if they aren't scored. The price of replacement costs for everything inside of that pump, even if they could be found, would probably exceed the cost of a new pump.

Anyhow, while I'm generally a tinkerer with stuff like that and enjoy seeing how things work, I can show you a pile of dead snowblowers that I was gonna fix someday.... It wasn't worth the time and effort VS buying new on those units.