There is no need of a longer push rod, it would not increase leverage and would in fact ruin the mechanics of the system. Too long a push rod and the brakes would have applied themselves when the oil got hot.
If it was all wrong then Mercedes would have fixed it ages ago.

 

Some scanners you can buy can bleed the ABS module, one line at a time or all together. The Autel Maxi Check ($175) is said to be one of them. We just need to find one for our car.
After going to the correct section you turn on the engine and press the button pedal and you can hear the ABS ticking and pumping brake fluid through the line selected, I think with the the bleed valve open you could get all the air out of that line and then do the rest. A buddy may be very handy to have about.
I have three scanners and I am going to see if any of them can do this.

 

I just read a short essay on the subject of brake fluid and would seem to be a good idea to change brake fluid about every two years, due to absorption of water. As far as I know, mine has not been changed in 5 years at least. I will do so immediately.

 

I would like to see if the car is able to use DOT5 fluid as it does not adsorb water and is a silicone based fluid with higher temp ratings. Does anyone know, the seals must be rated for its use. ? Woody

 

Not sure about compatibility with DOT 5. Interesting point you've raised. When I installed the SS brake lines & Speed Bleeder screws back in 2015, I filled the brake system with Pentosin Super DOT 4. I've always been curious whether the Pentosin DOT 4 LV would be an upgrade since the Spec Sheet states compatibility with DOT 4 systems and adheres to the same FMVSS & SAE Approvals/Specifications.

 

The PDF statement from The Service Manual is good enough for me.

 

Interesting that the Service Manual would state brake fluid must meet the DOT 4 specs and SAE J1703 standards. J1703 is the SAE standard for DOT 3 synthetic brake fluid. So I would interpret this to mean use DOT 4 spec brake fluid that meets or exceeds SAE J1703 standard. And nearly all DOT 4 synthetic brake fluid would exceed the SAE J1703 standard.

 

If I recall correctly silicone oil requires a special seal material.