park brake
 

NEED SOME HELP HERE. WHEN I DO MY BRAKE CHECK, MY PARK BRAKE (RED & YELLOW BUTTONS ) DO NOT POP OUT UNTIL AIR GAUGE'S BOTTOMS OUT. I HAVE REPLACED THE PARK BRAKE WITH A NEW ONE. THERE IS NO DIFFERENCE, IT WILL NOT POP OUT BETWEEN 15 & 40 LBS LIKE SUPPOSED TO. ANY IDEAS ? THANK YOU. TROY

Well,they are supposed to. When that air pressure drops to that point,the breaks set. They do that so that there is enough air to set the breaks for safety reasons. I'm not a diesel monkeynick,but that is the best that I can come up with. :P

....::EDITED::... :shock: :?

Sorry,I totally misread that. I am sorry,I thought that you wrote that your red,and yeller knobs DO pop out. Maybe a senser that tells them to pop out,isnt working? I'm sorry,not much help. :? Hope ya get r fixed.

Re: park brake
 

if your pressure gauges are correct..., install a new dash (push-pull) valve

THE NEW DASH PUSH PULL BRAKE IS WHAT I WAS REFERING TO AS PARK BRAKE. I DID INSTALL NEW ONE. SAME RESULTS. HOWEVER I HAVE NOT REPLACED THE AIR GAUGES. THEY SEEM TO WORK?? IS IT POSSIBLE THEY CAN LOSE ACCURACY ?

yes, but surely not simultaneously

on your keyboard; look to the far left, above the "shift" key and below the "Tab" key, the button is labelled "Caps Lock". press that key once

thank you,

p.s. - when you type with all caps it indiCATES THAT YOU ARE YELLING AT ME!!!

and......... my last nerve is already hanging on by a thin thread ;0)

thanks for the response bob. didnt mean to yell. i must have caught that from my wife . lol

I've seen that happen in other trucks as well. I think the forces (air pressure vs spring pressure) balancing that valve are so low by the time you're down to 45 psi, any O ring that has a little too much drag is enough to hang it up. The only thing I could suggest is to try to dribble a little air-tool oil into the valve to lube the o ring that seals the knob shaft.

hey now get this.. ready?.. here goes... when i do my brake check engine off & key on the buzzer & light work just like supposed to. the brake valves do not pop out until the air gauge bottoms out. maybe 2-5 lbs at most.. but... but... if i do brake check with engine running the valves pop out between 25- 40. tried 12 times. pops out every time. i just pump brakes faster than my ole won out compressor can replenish & out they pop. let it build back up & pump down again & pops out just like it supposed to.. one more thing.. is this type a problem a shut down offense if a had to do a full insp at scale with the d.o.t ? thank you. i know bob will have imput here.. :lol: