How about some more info for starters, we're not mind-readers. Year/Make/Model? How much of the system has been apart? Did you bench bleed the master cylinder? What procedure are you using to bleed the system? Devon
my bad on that 70 gs 455 front disks rear drums. trying to use a hand vac pump system the new fluid keeps coming along with air and alot of it and it never runs out
and i parked it about 5 months ago had brakes when i drove over to my dads when i went over there to bring it home put in gear and it started rolling so i put it up on the lift to bleed it and non stop air
You're either getting air from a leak in the system somewhere upstream (cracked line or flex hose) or you're pulling air past the threads on the bleeder screws. Try pressure bleeding with the pedal to see if you can find a leak somewhere; you might even find pressure bleeding solves the problem. Devon
Just a suggestion but as over 30 years as a Mechanic has taught me to never PUMP THE PEDAL!! Once you are sure you do not have a leak fill the master cylinder & go to the RH Rear (passenger side) Brake & open the bleeder. Now have another person push the Brake Pedal to the Floor SLOWLY. Once the Pedal has bottomed out while leaving it on the Floor,shut the Bleeder. Now foot off the Pedal, wait a few seconds then reopen the RH Rear Bleeder & slowly push it to the floor again. Repeat this proceedure as many times as need to get a pretty nice stream of fluid when depressing the Pedal. Next move to the LH Rear (Drivers Side) & repeat the same proceedure,then on to the RH Front & lastly the LH Front. After you do all wheels go back over them again using the same proceedure. Also keep checking & filling the master cylinder often as you go along. I found that pumping the Brake Pedal often mixes Air Bubbles with Fluid which is not something you need while bleeding the brakes. Hope this helps! Doug
Just have to add that I don't recommend full stroke of the pedal for this process unless a new master cylinder was installed. Going full stroke on an old MC pushes the piston seals into uncharted territory that can be full of gunk and debris, which is why some master cylinders fail due to internal leakage shortly after the system has been bled. Devon
Devon, That is a very good point but if that is all it takes to send the Master Cylinder out I would not want to trust it to stop my Hot Rod. I would change a nearly defective Master Cylinder now rather the wait for it to decide when to fail later! Doug
Easy to say when we're working a car we're familiar with, but if you're working on an unkown (somebody else's) it can be a different story. Devon
Mityvac makes a pressure shooter I think its called the Hydraulic Injection System or something like that. It allows you to pressure bleed from the master cyl out to the wheels. It is a hand pump quart tank that you fill with brake fluid then pump up. Works great
The dirt in the master is a very common problem with late 80's early 90's mopar master cylinders and will tear the seals in a hurry. I also thought that below was the only way to do it with out needing special tools. I have a Motive power bleeder and it works great but it is messy as it doesn't seal on top of a flat rectangular MC very well.
a few monthsa ago, a pressure bleeder using compressed air was used on the "two guys garage". u do not attach it to the top of the master cylinder but to the bleeder screw assembly at each corner. it forces the brake fluid uphill to the m/c. $450? in my opinion. i like the idea.
If the booster holds a vacuum I probably wouldn't mess with it. Take a close look at it when the MC is off in case it got a lot of brake fluid contamination from the leak, though. Devon
