replacing B1 piston

[Pete Burton]

with a self adjusting one....anyone have experience on how well this works out? Does it improve the 1-2 shift any?

[C32AMG]

The self adjusting B1 pistons were used on some models 722.3 and 722.5 transmissions. The ones I seen lost their adjustment, transmission slipping. I change them to the second designed B1.

MB is guilty of over engineering, give me an adjustable bolt and lock nut so I can make my own adjustment.

[Pete Burton]

What is the second design B1 then? I spent a bunch of time talking to the local dealership. They have 1 B1 piston type available, so I ordered it. I agree with you, I'd rather adjust it myself. I have 2 pistons with different fixed lengths. the longer one still needs to be 2 - 2.5 mm longer, based on the measurement I made with what I hope is the correct type tool. i made one from a B1 piston cover, welded a M8 x 1.0 nut on it, screwed to resistance, then torqued to 1 Nm.

[C32AMG]

The 2nd design B1 piston is the one with the removable pressure pin, part# 126 270 97 32; 71 mm. you may need the plastic band support depending on your 722.3xxxxxxxxxx number.

Adjustment shims 0.5mm part number 000988 008015
1.0mm 000988 008006
1.5mm 000988 008024

The tool you are using is the right home made one, to use it, one complete turn of the bolt must equal 1mm of bolt travel. I had to buy a new one and more when one of my tool boxes disappear, Full with MB transmission specialty tools. If all else fails set the piston travel to .125”

I bought the self adjusting 3rd design with the intention of using them on all my rebuilt until I found out the hard way they lost there adjustment.

B1 PISTON

[Pete Burton]

Steve, thanks again for this specific information. For me, it's been tough to find the right information. Knowing that the 3rd version piston has an issue with losing it's adjustment is really important. If I put that in and had problems down the road, I'd be kicking myself.