audi a4 b9 brake problem

[tysonaly8]

I am new here. I have had a faulty abs pump problem, which is very common in Saudi a4 b9 . after getting it removed I sent the abs unit to "ecutesting". and after receiving it back, I called a mechanic to fix it, now I don't have any light on the dash whatsoever, but there is a problem. after bleeding brakes each wheel and spending 2 hours. brakes are not working, the pedal is soft as anything, we even changed the servo sensor beforehand. and there is a hissing sound coming from the master cylinder. I am completely baffled and don't know what to do, the mechanic said it could be the master cylinder leaking and we have to replace it, but he is not entirely sure about it. please help

thank you

 

[NHN]

Clearly if it's hissing around the servo, MC then it's not sealed, he needs to look at replacing any seals or the servo etc, it's one of those jobs where replacing stuff, unless obvious here the fault is, is the best way forward, given that's where the work has been done, then logic suggests it's this.

 

[tyson-aly]

Clearly if it's hissing around the servo, MC then it's not sealed, he needs to look at replacing any seals or the servo etc, it's one of those jobs where replacing stuff, unless obvious here the fault is, is the best way forward, given that's where the work has been done, then logic suggests it's this.

hi, thanks for your reply. but what baffles me is that it was working fine before removing abs can you fix it? if you live around north west London side.

many thank s