ALB Adjustment: VW T4 Brake Force Limiter Calibration

Hello!

With my T4, I have a problem where the rear brakes are applying too much force.
Unloaded. I need to drive it occasionally so the brake discs don't rust, but when I brake hard, it locks up the rear wheels.
That can be quite dangerous, even in the winter.

I looked into this on the T4 wiki, and apparently you need two pressure gauges there. One at the front, showing 50 bar, and one at the back, showing 20 bar, with the axle in a defined position.

It's strange that there are hundreds of these T4 pickup trucks driving around here, but no workshop knows anything about them or has the necessary testing equipment.
Even at VW, the master technician couldn't give me a reasonable answer as to whether they could do it "properly." "I'll have to ask someone, but they're not here this week... I don't even know if we have the equipment for that..."

It appears that the brake force distribution system is still working, but it is likely misconfigured.

Can someone provide some input on this?
I really wanted to do it properly.

... or was replaced with a fake in the past. I once encountered this with a customer. They often just get stuck.

So, everything that moves is easily movable. When you apply the brakes, it also moves slightly.
It was like that at least six months ago, but I should probably double-check tomorrow just to be sure.

Unfortunately, the term "Hebel gängig" doesn't have a direct or common translation.
The pistons may also be stuck, in which case nothing will happen even if the lever moves. This is more likely to occur if the system is operated at the same level for a very long time.

Why don't you go to a brake testing station at TÜV & Co. when it's not busy and have your brake values checked? With my last T4, I practically adjusted the BKR (brake force regulator) on the brake roller until the inspector approved it.

Hello!

So, the brake force limiter is working; it's at least moving when the brake is applied.
I adjusted the springs to have less pre-tension.
Now, the rear wheels of my car no longer block the gravel parking space.

@Rüdi:
Do you have a braking value for the rear axle when the car is unloaded?
0.9 liters according to the reading on the test bench?
My gut feeling would tell me that.

Unfortunately, I no longer have the data; I had a document from VW for it, but I lost it.

"90 is definitely too low, I mean, the Multivan had a value of 180 in the back."

Hi!

Too bad, well, I'll have to ask the TÜV inspector.
But it was really about the mindset. I drove on the road again yesterday and really slammed on the brakes.
Now I can really put my foot down on it without it getting blocked from behind.
So, things have changed.
I adjusted it by 1 cm on both sides.

Hello!

Today, I had a lucky opportunity: My father loaded garden waste onto the T4 van.
Unfortunately, because it was a double cab, the entire load was directly on the rear axle.
I drove my car to the brake testing machine at the workshop next door.

Okay, loading:
Front: 3.3, Rear: 2.0.

I took the stuff to the composting facility and got a weight certificate.
That was a payload of 190 kg.
Then we checked the brakes again on the dynamometer, and the rear brakes were reading 1.5.

I already noticed that the regulator was failing when I was on the brake tester.
You can press that pedal as hard as you want, but it won't go above 2.0 or 1.5.

Does anyone have any benchmark values? Do you think I can leave it like this?

Unfortunately, I haven't been able to find any workshops in the area that can properly adjust the brake force limiter.
Neither VW workshops.