Weak Pneumatics 42043

[Rebel_Lego]

Hi, 

I stored my MB Arocs for about half a year. I rebuilt the B model into the A model, but the pneumatics just won’t work. I looked for any kinks in the hoses, tried the pump, tried the cilinders with nothing attached, and it all works fine. The cilinders are also re-oiled. If I attach the first section of the crane, it works fine. However, if I put the second section on, the cilinder can’t lift the crane. The problem lies just with the first cilinder. I even swapped the cilinder for the second section with the cilinder for the first section, but both cilinders seam too weak for the weight of the crane. I’m not really experienced or anything with this kind of stuff, I just build and play, and if I make MOCs its certainly not with pneumatics. I read several forums but all the solutions given there were the things I already tried. 

So, has anyone an idea what this might be? Maybe because I stored my Arocs the cilinders caught too much dust?

PS. I also thought about adding an air tank, but I don’t know if that solves the problem?

[Maaboo the Witch]

Have you tried letting the air pressure in the system really build up before actuating/moving the crane? Especially if you've left it idle for a while the system won't respond well.

[Rebel_Lego]

You mean just let the pump run for a few minutes?

[Maaboo the Witch]

4 minutes ago, Rebel_Lego said:

You mean just let the pump run for a few minutes?

Not a few minutes, no. Try 30 seconds or so. Just let a decent amount of air into the circuit.

[Rebel_Lego]

The crane now moves reasonable, but not as fast as before. Is this common with pneumatic cilinders? I mean, is it common that over time they loose some of their strength?

[Maaboo the Witch]

Just now, Rebel_Lego said:

The crane now moves reasonable, but not as fast as before. Is this common with pneumatic cilinders? I mean, is it common that over time they loose some of their strength?

I don't know about that, not that I've observed. But keep pumping air and the cylinders should start moving better.

[mwyns]

I've 2 trucks with the same problem after some time. The solution was to replace the blue pump with the newer reinforced version from set 42080. When you contact Lego they replace it for free.

[Maaboo the Witch]

2 minutes ago, mwyns said:

I've 2 trucks with the same problem after some time. The solution was to replace the blue pump with the newer reinforced version from set 42080. When you contact Lego they replace it for free.

That could also help.

[amorti]

What have you oiled the cylinders with? I'd imagine anything from mineral oil would degrade the seals.

[Andman]

1 hour ago, Rebel_Lego said:

So, has anyone an idea what this might be? Maybe because I stored my Arocs the cilinders caught too much dust?

I had the same issues some month ago. It turned out that the pump had micro cracks around the bottom. That's why it couldn't build up pressure to the cylinders. To test that close the air outlet with a finger and push the rod into the pump. Keep it pushed in for a couple of seconds, 10 should be enough. If the pump is tight, the rod should move back to the initial position. If it doesn't move back at all or just a little bit, then your pump is not broken.

[Nazgarot]

Hi.

Both the pump and the small cylinder of 42043 has been reported to have problems. Try removing the small cylinder form the circuit and test again. On mine it was leaking ever so slightly and was replaced by TLG after I complained.

-ED-

[Rebel_Lego]

10 hours ago, mwyns said:

I've 2 trucks with the same problem after some time. The solution was to replace the blue pump with the newer reinforced version from set 42080. When you contact Lego they replace it for free.

Will they replace the pump free in a model that’s 5 years old?

10 hours ago, Andman said:

I had the same issues some month ago. It turned out that the pump had micro cracks around the bottom. That's why it couldn't build up pressure to the cylinders. To test that close the air outlet with a finger and push the rod into the pump. Keep it pushed in for a couple of seconds, 10 should be enough. If the pump is tight, the rod should move back to the initial position. If it doesn't move back at all or just a little bit, then your pump is not broken.

I will look for this.

7 hours ago, Nazgarot said:

Both the pump and the small cylinder of 42043 has been reported to have problems. Try removing the small cylinder form the circuit and test again. On mine it was leaking ever so slightly and was replaced by TLG after I complained.

Do you think Lego still replaces these parts after five years? I never before asked for replacement parts, so I don’t know.

[Andman]

1 hour ago, Rebel_Lego said:

Do you think Lego still replaces these parts after five years? I never before asked for replacement parts, so I don’t know.

Yes, it's likely that they will replace it.

[Rebel_Lego]

@Andman: Wow, that’s great! If I find some time (problably tonight) I will take a closer look to the pump to see if it leeks and will also look at the small cilinder, as @Nazgarot suggested. Thank you all for your answers!

[andrzejl]

I bought new Arocs in October last year and had similar problems - most functions worked (albeit quite slow) but it couldn't lift the crane at all. Faulty pump was the problem, Lego sent me a new one and it was the newer version.

[Rebel_Lego]

23 minutes ago, andrzejl said:

I bought new Arocs in October last year and had similar problems - most functions worked (albeit quite slow) but it couldn't lift the crane at all. Faulty pump was the problem, Lego sent me a new one and it was the newer version.

And did it work?

[mwyns]

11 hours ago, Rebel_Lego said:

Will they replace the pump free in a model that’s 5 years old?

I've got my free replacement after 4 years.

Edited March 13, 2021 by mwyns

[howitzer]

23 hours ago, Andman said:

I had the same issues some month ago. It turned out that the pump had micro cracks around the bottom. That's why it couldn't build up pressure to the cylinders. To test that close the air outlet with a finger and push the rod into the pump. Keep it pushed in for a couple of seconds, 10 should be enough. If the pump is tight, the rod should move back to the initial position. If it doesn't move back at all or just a little bit, then your pump is not broken.

I have two of 42043 and at least one of the pumps appears to be faulty one, as I do this test, it only moves a little. Couldn't test the other one right now as it's inside a build but I wonder if all Arocs pumps are faulty or just some of them?

[Rebel_Lego]

20 hours ago, mwyns said:

I've got my free replacement after 4 years.

I ordered the pump yesterday, I hope they send it tomorrow.

Edited March 14, 2021 by Rebel_Lego

[andrzejl]

23 hours ago, Rebel_Lego said:

And did it work?

Yes, it works perfectly now.