All ActivityMost RecentMost LikesSolutionsRe: 76 Dodge Sportsman Class C, Brake Issues, wont hold pressureHey all sorry for the late response. I talked dad into changing the hoses even though they appeared to be "ok", we cleaned the proportion valve and adjusted the shaft in master cylinder and WAHH LAHHHH brakes! I still believe that it was the hoses because that's the only thing that made sense after trying everything :) Thanks everyone for your help! Lori KrystofRe: 76 Dodge Sportsman Class C, Brake Issues, wont hold pressure navegator wrote: Old brake hoses some times swell internally, they look ok but are restricted inside, when the pedal is applied there will be pressure on the pedal as the fluid slowly pushes against the soft internal walls pushing and creating a dam of soft rubber at the lower end of the hose where it is not damaged, the pressure is lost slowly as it passed the restricted area, bleeding the brakes will be normal since there is no pressure to push the soft internal walls of the hose towards a hard point blocking the little bit of hose, after a few seconds the fluid starts getting past the restriction and the pressure is taken up by the piston on the caliper, since it did not move to begin. The solution is to replace all the hoses and also check that the brake pedal and the booster push rod that goes into the master cylinder are at the correct length, the other possible problem area is the master cylinder if it is manufactured in China or India or some where else instead of the USA. Some years ago I had an auto repair shop and I had to specify American made parts or German or Swedish or Japanese made because the Chinese or other manufactured parts were nothing but junk, when time equates to money earned those junk parts are a loosing proposition, master cylinders, remanufactured generators, some brake boosters and power steering pumps as well as power steering racks that are made in Asia are notorious for junk, cheap does not equate with quality, specially when it pertains to brakes, to many lives depend on them. navegator Thank you so much! I will pass info onto pops and then get back soon!Re: 76 Dodge Sportsman Class C, Brake Issues, wont hold pressureHey guys haven't forgotten about you all. It has been a cold busy weekend/week. I will update you all as soon as me and dad get the work done! Replacing hoses, trying new MC and have been studying the Proportion Valve. Will update soon. HAPPY NEW YEAR ! David and LoriRe: 76 Dodge Sportsman Class C, Brake Issues, wont hold pressureHey guys haven't forgotten about you all. It has been a cold busy weekend/week. I will update you all as soon as me and dad get the work done! Replacing hoses, trying new MC and have been studying the Proportion Valve. Will update soon. HAPPY NEW YEAR !Re: 76 Dodge Sportsman Class C, Brake Issues, wont hold pressure fourthclassC wrote: Well, what was the root cause. I bet every one would like to hear the happy ending story. Well it has been a busy cold weekend/week so far so nothing has been done yet! I will give you all an update! Going to replace rear hoses, may try a different MC and got some feedback on a different site about the proportion valve. Will check bavk in soon.Re: 76 Dodge Sportsman Class C, Brake Issues, wont hold pressureWell we got fluid (2 squirts in MC) when checking the push rod...... pressure builds up great then wait not even a minute and have to pump back up again....Re: 76 Dodge Sportsman Class C, Brake Issues, wont hold pressureHey guys thank you so much! I'm going to help my dad right now" this is second suggestion about the push rod so we are going to check that first. I will get to you soon! Thanks again! David and LoriRe: 76 Dodge Sportsman Class C, Brake Issues, wont hold pressureThis is second master cylinder I've tried brand new not manufactured. I moved cylinder from power booster and there was no fluid leaking past back into the booster.Re: 76 Dodge Sportsman Class C, Brake Issues, wont hold pressureBrand new master cylinder. It took all fluid needed to fill MC from the wheels but the pressure just doesn't hold.Re: 76 Dodge Sportsman Class C, Brake Issues, wont hold pressureI replaced both the fronts and the rear is still solid