have a 87 ford f800 dump,the parking brake does not disengauge with yellow push release.one day it worked and next day stopped working.i am new to this area of expertise.can anyone help..
Get someone to stand at the rear of the truck when you push the button. There should not be the steady sound of air. If working right, the air pushes a diaphragm and you should hear a little puff of air moving and maybe a squeak from the brake mechanism releasing. If you hear lots of air, the diaphragm is shot. Easy to fix if you know what you are doing. If not, get help because screwing with this in the wrong way has to potential to be the cause of your death. There is a big, strong, compressed, spring inside of the air can.
we have replaced both cans awhile ago,truck maybe has 5 miles on it since.there is no sound at all when applied or released,like the arm isn't even attached,very strange to me,but like the old saying goes... nobody knows nothing,it was fine when I drove it kind of deal........
Make sure the slack adjustor is in adjustment and travels free.
Does the button push in and not stay pushed in (pops right back out) or does it not push in? If the former then look at your air pressure it may be to low to release the park brake.
the knob does push in all the way in really easy like it is not connected.but it is connected.cans were pre-adjusted when purchased.fluid level is up,everything else works just fine.Cuold it be the valve in which the rod is connected to?
I was also wondering how to check air pressure for system.
Last one of those I saw had the Lucas Girling "hydraulic-but-wish-they-were-Air" type brakes. Are we sure thats not what we're dealing with?
I am sure it is Lucas Girling,because there is fluid with system.
PM me your email & I'll send you the material I have on those systems. You said the button pushes in have you cracked the bleeders back @ the cans to see if you have fluid under pressure?
believe it or not I was just talking about that same thing,crack bleeders...my [email protected] -thank you so much.....
one question,do I do that running or not? crack bleeder?
Running, brake release pushed in. IIRC Should be 2 bleeders 1 for brake release and 1 for service brake
Email sent with the factory training material. I hope that helps. keep us posted
I have tried to bleed the cans with running vehicle.air pressure does not build up,there is no pressure at all.can it be the valve the yellow knob is connected to?i have tried this a few times,and still nothing.Any other ideas?
If you have the hyd park brakes you will never have air presser it will be red transmisson fluid. If you have never been around one it allways fills like the yellow knob is not doing any thing. Is your resover full of fluid?