[QUOTE=AuSeeker;3830693]In your very 1st post in this thread you stated...

"I have not had a car with such complicated brake booster/ABS than the 4th Gen.
My brakes quit 3 years after I bought the 4th Gen (2002 model)."

My question is what year is your T4R actually, a 2002 or 2003, I ask because a 2002 is a 3rd Gen not a 4th gen?

That being asked, at this point I would replace the entire master cylinder/booster assembly, a bit pricey at about $1300 to $1350 +/- depending on source but it should solve all of your issues provided you get all the air out of the system after installing the assembly.


Hi Auseeker,

I misspoke, I have a 2003 T4R with a 4.7 V8. So I have this diffcult to maintain electric motor assist Brake/ABS unit that is not well understood (by myself) as I simply know the old system with the idiot proof vacuum booster and add on ABS of my older Mercedes.

As I know hydraulic systems very well (I am a mechanical engineer) i would need the hydraulic diagrams or true sections of this unit and some data in order to understand the functions, maintenance and repairs better.
I believe I could do a much better job this way and don't ask stupid questions.


For sure I could buy a new unit and install and most problems would be solved... but I love these mechanical challenges and I am happy to drill into it and learn.

I'll look into the manual excerpt.

Thanks, Martin