Cat hydraulic tank leak

[joshs]

Hello - I've recently developed a leak on the hydraulic tank on my 247b3.
It's leaking from the fitting here. It leaks from above the 6 sided plastic part.

The parts catalog doesn't list this fitting separately from the tank, or any seals, etc. Does anyone know if this connection is repairable, or the entire tank needs to be replaced?

Thank You!

 

[heymccall]

At $1,581.74 for the tank, and the fact that is a different material than the tank itself, I'd sure try to turn it to see if it's removable/ resealable.

 

[Mobilewrench]

Ran into that on a cat b3 last year. Even though the fitting has a hex, it is part of the tank. I had considered using pvc fusing tools to reseal it, but decided I only wanted to pull the tank once.

 

[joshs]

At $1,581.74 for the tank, and the fact that is a different material than the tank itself, I'd sure try to turn it to see if it's removable/ resealable.

For that price, I'll definitely be trying to replace the fitting with a new one. Is it permissible to use any sealer in the tank like RTV? If I an get the old fitting out without damaging the tank, I should be able to use something like this assuming it's small enough to fit through the fill cap.
https://www.mcmaster.com/bulkhead-fittings/plastic-pipe-fittings-for-oil/

Another thought I had was seeing if any local fabricating place could make a tank out of steel or aluminum. Seems like that could be done for less and would last longer. Not even 1,000 hours on the first tank.

 

[heymccall]

Have you consulted with your Cat dealer?

 

[joshs]

Have you consulted with your Cat dealer?

I talked to the one I bought it from Friday and they thought it had a replaceable fitting with an o-ring. I'll call a different one Monday that deals more with mtl's now that I see the parts list doesn't list any such parts. I'll definitely confirm what a new replacement costs and that they are available before I evem pull the old one. It's not leaking a huge amount and I don't need it anytime soon. It's been leaking for a while the way it looks.

 

[Nige]

I had to "phone a friend" on this one.......
That's where the 348-4609 hydraulic suction screen fits. There is a 5W-6388 O-Ring behind the hexagon, you can see it in the photo below.
See attachments. Drain the hydraulic tank, remove & clean the suction screen, fit a new o-ring, and tighten to spec.?

 

[joshs]

I had to "phone a friend" on this one.......
That's where the 348-4609 hydraulic suction screen fits. There is a 5W-6388 O-Ring behind the hexagon, you can see it in the photo below.
See attachments. Drain the hydraulic tank, remove & clean the suction screen, fit a new o-ring, and tighten to spec.?

View attachment 266496

Well that'd be awsome. Strange that that image looks metal, not plastic, and doesn't have any threads but maybe not a photo of the exact part. I'll drain it in the next few days here and see if I can unscrew it. If it does, it seems like there would be enough room to get it out without even removing the tank.

 

[joshs]

I had to "phone a friend" on this one.......
That's where the 348-4609 hydraulic suction screen fits. There is a 5W-6388 O-Ring behind the hexagon, you can see it in the photo below.
See attachments. Drain the hydraulic tank, remove & clean the suction screen, fit a new o-ring, and tighten to spec.?

View attachment 266496

Unfortunately for me this doesn't appear to be the tank on mine. Looks like this one starts at TSL1xxxxx. Mine is TSL0xxxxx. My current tank is 347-4035 and it seems the new replacement tank would be 347-5346 which has the strainer.
Newer tank:

Mine:

 

[Nige]

The photo shows the screen from the other end. In other words what you’re looking at is out of sight up inside the tank. All you’ll see from the outside is the hexagon and the short spigot onto which the suction hose fits.

If you take a look at the two pdf attachments together they explain it a bit better. The parts drawing is not clear but does list both the screen and the o-ring and from the specification drawing it’s indicated the fitting has to be tightened to a certain torque which means it must be threaded into the tank.

 

[joshs]

The photo shows the screen from the other end. In other words what you’re looking at is out of sight up inside the tank. All you’ll see from the outside is the hexagon and the short spigot onto which the suction hose fits.

If you take a look at the two pdf attachments together they explain it a bit better. The parts drawing is not clear but does list both the screen and the o-ring and from the specification drawing it’s indicated the fitting has to be tightened to a certain torque which means it must be threaded into the tank.

I just went out and tried turning it to see if it would turn even without draining the tank, and it turned like it's threaded. Left it turns, and if you go right, it stops after a bit.

It took no where even close to 50 ft lbs to break loose. My channel loc is too small to even grab it and it just started loosening. Basically hand tight at best. Probably why it is leaking. I'm right at 1000 hours, so good time to replace the hydro oil and filter, and that screen. I'll drain tomorrow and confirm the screen comes out and get it ordered. Thanks!

 

[Nige]

Looks like this one starts at TSL1xxxxx. Mine is TSL0xxxxx.

I think you are falling into the same trap that a lot of others fall into. “TSL1-Up” is Cat shorthand for “from first machine built”, or TSL00001 in other words. As far as I can see the attachment that I posted above showing the strainer is valid for all machines of TSL prefix. I will double-check that in the morning and get back to you.

If the screen is metal as it appears from the photo then you should be able to clean it with diesel and refit. All you would need is a new o-ring.

 

[joshs]

I think you are falling into the same trap that a lot of others fall into. “TSL1-Up” is Cat shorthand for “from first machine built”, or TSL00001 in other words. As far as I can see the attachment that I posted above showing the strainer is valid for all machines of TSL prefix. I will double-check that in the morning and get back to you.

If the screen is metal as it appears from the photo then you should be able to clean it with diesel and refit. All you would need is a new o-ring.

Mine's definitely plastic, but maybe they changed it at some point to metal. I'm going to pick up a bigger channellock and just see if tightening it to the torque spec fixes the leak until I get time to run in and pick up new oil and a new screen. It was only hand tight at best. Good to know about the serial numbers. I've not seen it done that way on my other equipment.

 

[Nige]

My current tank is 347-4035 and it seems the new replacement tank would be 347-5346 which has the strainer.

347-4035 is what's known as a "non-serviced Part Number", in other words one that is not available separately via the Parts system.
The 347-4035 tank is one of a list of parts that make up the 347-5346 Tank Group. The Tank Gp comprises the tank itself, the sight gauge, the strainer assembly, and the O-Ring. The last 3 items are available as separate parts, the tank is not.
So basically we're talking about the same thing.

 

[joshs]

347-4035 is what's known as a "non-serviced Part Number", in other words one that is not available separately via the Parts system.
The 347-4035 tank is one of a list of parts that make up the 347-5346 Tank Group. The Tank Gp comprises the tank itself, the sight gauge, the strainer assembly, and the O-Ring. The last 3 items are available as separate parts, the tank is not.
So basically we're talking about the same thing.

View attachment 266538
View attachment 266537

It sounds more complicated than it should be. Parts was not able to find the part until I gave them the exact part number. He was heading down the path that the tank needed to be replaced before I said "what about 348-4609?". Thanks so much for your help! Is there any specific procedure for draining/refilling the hydraulic oil than what would be in the operation manual? I have to pull my cab back down so I can get to my manual.

 

[Nige]

It sounds more complicated than it should be. Parts was not able to find the part until I gave them the exact part number. He was heading down the path that the tank needed to be replaced before I said "what about 348-4609?".

I agree. The Parts Manual is not at all clear and it was only when I found the specifications that it made sense where the strainer was located and that it screwed into the tank. As I mentioned above I contacted a friend who works on this line of machines and he was the one who asked if the leak was at the location of the strainer. So thanks Chris..!

Nothing special about changing the oil that I can see other than what's in the O&M Manual.

 

[joshs]

Well, the new screen and o-ring fixed the leak. There was some issue with the old screen. The screen itself was not seated correctly into the fitting. I wonder if that contributed to the seal failing. Unfortunately, something I must have done replacing the screen broke my a/c. I had it running when I drove up on the ramps to change the screen. Started it up after and now the air conditioning won't turn on.

 

[joshs]

Found it. To replace the screen, I had to lift the hydraulic tank up an inch. There was an extra ground wire attached to the tank bracket that fell behind the tank and didn't get re-connected. All good now. Thanks for all your help Chris as Nige!