mercedes benz 305 bus park brake

[wombatwomper]

Hi everyone thanks for having a look at our problem we have a 1979 ex sydney council bus which we love and want to get it moving to a site where it can be worked on, it runs well and is only just out of rego the problem is the park brake is stuck on due to a safety mechanism. Our good friend who has a lot of experience as a mechanic is working on it and we are currently mapping the air system and working where the air is going and not going. We have a couple of things to ask one is does any one know of a way to bypass some of the system to get air to the park brakes and the bus seems to take a bit of time to get air everywhere and a red light stays on on the dash for the air does anyone know if this warning light is connected to the park brake staying on. Thank you for helping and have a great day Stu

[Guy_Arab]

perhaps your program is the four way valve Most needs changing
Guy Arab

[DiAmOnD T]

There is an emergency air fill located at the front of the bus, look under the bumper roughly inline with the left hand wiper arm, but as Guy_Arab mentioned, if your 4 way valve is jammed it wont pass any air through the system to the brakes.
There are a couple of pressure switches which control the lights on the dash, it could be a wire off or simply the lack of air keeping the light on