Pneumatic Hose Burst: Causes & Troubleshooting

Today, I accidentally stumbled upon the cause of some common problems with the ALH.
I noticed that the engine was vibrating strongly when I turned it off.
Hood on... The diverter valve doesn't engage when shutting down.
Pneumatic relay tested -> OK.
Hoses tested -> OK.
'The hoses were inspected, and it was found that one of the three hoses at the Y-branch had ruptured beneath the fabric, which had reduced the pressure throughout the entire pneumatic system.'
Following -> Poor engine performance -> Increased fuel consumption -> Reduced braking power.

Interestingly, since the repair, the engine starts warm better than it did in the years prior.

Unfortunately, my wife has been driving the car for almost 40,000 km. So, it could have been like that for a very long time. I don't even want to think about how much money has been wasted and gone up in smoke through the exhaust. }

It's understandable that components like the brake booster, turbocharger boost pressure control (only in VTG systems), shut-off valve, and exhaust gas recirculation system won't function correctly when there's a lack of vacuum... everything relies on the vacuum system.

But it's certainly interesting - this could explain a connection in cases of mysterious symptoms.

Unfortunately, I didn't mention that my wife thought the car had poor braking performance.

Then I started looking for issues with the brake discs and pads because the vehicle was due for its technical inspection (TÜV).
It was only by chance that I noticed the engine stuttering when I turned it off.
After the repair, the fuel consumption decreased from 5.3 to 4.9 liters, despite the use of biodiesel.
The sound of the loading pipes is clearly audible again.

At VAG (Volkswagen Group), they would have definitely started by completely replacing the entire braking system, then the brake booster, and who knows what else. You can't just easily fix something like that.