My dad's '08 has a brake pedal that hisses from under the dash whenever it's released; when the brake is applied at all the hiss goes away. This hiss is constant when it happens, but it's came and gone a couple times now; we've had a couple weeks of constant hiss, a week of no hiss, and are now on another couple weeks of hiss.

Anybody else have this problem? TSB?

What would it be?

 

man i dont know. mine dont do that

 

i had an f150 that hissed til u stepped on the brake, there were some bad seals in the booster.

 

There was a gentleman that had a similar issue with his 07.5 in another forum that I remember. This turn out to be a failed brake hose, the liner which is Teflon had failed and was extruding in to the booster. He finally replace this hose and the hissing went a way. I believe that this was the return hose that failed. He posted pictures of the failed hose on two different forums, check them out.
This may or may not be your problem but it would be a worth while for you to check.
PM me and I will look for the thread if you can not find it.

 

I had the failed liner in the power steering hose to the booster. Basically it was as described with the liner out of the hose coming loose and causing a blockage to the booster. I was concerned it was the booster but relieved it was only a hose. 2 Dodge techs on the TDR diagnosed it over the web in minutes... Seems to be a common failure..

If you don't mind heading to another thread/site I have photos etc.

http://www.dieseltruckresource.com/d...s-t255765.html

or

Power Steering/Hydroboost hiss - TDR Roundtable

 

I have the same hissing noise comming from under the dash. I hope this is the only problem. I have lost my job now for a few months and the dealer is saying my warrinty don't cover this issue. I hope this won't lead to a bigger problem. I have also had the turbo issue but after the fixno more problems. Send pic's of what line is the problem maybe I can fix it myself.

 

IT'S FIXED!!! It was the brake booster or better known as the hydrolic seperator well this is what the dealer told me anyway they replaced the booster and the booster line and there is no more noises ah quite again.