Hitachi 75zxUR oil leaking from between pumps.

[HarleyHappy]

You aren’t purging with argon for safety, you do it for less porosity and cleaner weld.
Was always taught that the argon just keeps cleaner.
For safer on gas tanks, just run some exhaust fumes in the tank.

 

[LCA078]

I'm assuming it's a pressurized hydraulic tank? If so, an epoxy like JB Weld may work...for a bit. If you use epoxy as a quick fix, I would rough up the surfaces so the epoxy has some tooth. But I'm worried that the reason the crack appeared is from vibration or other movement which means the epoxy would probably eventually fail.

If you do pull the tank and weld it, I'd consider adding a reinforcing collar to help spread out the stress points

 

[Chantrelle]

Yea I had a welder friend come by yesterday and he agrees tank should be pulled for best welding results.

And ..
It’s not my only leak.

I ran the machine a bit yesterday and once it’s fired up and warm a little leak starts to creep out from between the two pumps as I have stated before.

I washed and dried everything around the pump today and determined that there was no leak when the machine was just sitting.

I turned it on and turned up the idle and moved the arm around and after a bit the leak came back. It’s pretty hard to get a really good look in their but it sure seems like it come out from between the pump faces at the lowest point.

There’s two other possible spots it may be come from. I will include pics.
One spot is from behind this plate on the top right side of pump. Or from behind the bolt below it. In the picture my thumb is on a big bolt that the plate is behind. And my pointer finger is on the bolt below it. I do not know what is behind either th epilate or the bolt.

The other spot is behind a bolt at the bottom of the pump. Also not sure what’s behind it.

In the picture it does appear like there a little oil droplet above the bolt where the pump faces meet.

All this to say. If it come from between the two pumps faces. Beyond replacing the two o rings I’ve already replaced multiple times. Should replace the shaft seal? Or is it impossible that this leak is a result of the shaft seal.

I feel like I’m going in circles a bit with asking this question. I think it’s a bit unclear to me based on different answers. Apologize if it seems I’m repeating my self here.

Any helps appreciated. Cheers.

 

[Welder Dave]

The most important thing when welding a crack on an oil tank is getting rid off all the oil residue. Argon won't magically do that. Argon purge is basically the same as CO2 purge to prevent anything burning or exploding. Heating it to burn it all out and grinding the area so it's clean steel is the best way. Argon might help if the crack is Tig or Mig welded. If the reservoir is removed it could be steamed and the crack put at the top for welding. Would still want to heat it up to be sure there's no oil residue.