Hey, um I'm new ish to the site. Hope im posting in the right spot. So my first post is about trying to get ideas on other places to look and check. My rig is an 88 f350 quad cab 5-speed 2wd dually. So my problem is eng running hold the b pedal and it slowly sinks to the floor. My first thought was master. Second was booster. Third was pin hole some where. And finally to double check all fittings and bleed the system. This all started cause my clutch went out and my inspection is dead. So knowing I haven't done the rear brakes.........I did them. Along with a mass of other normal maintenance that I did, when it came time for the brakes I did the following.
Rear shoes (all)
Rear drum hardware (all)
Wheel cylinder (all)
Front pads (all)
Master cylinder (new)
Booster (reman)
Full Rear line replacement from master to both rear wheel cyl (w/correct fittings)
So I put the new master, booster, and lines in only through different stages of massive aggrevation trying to guess where my air is coming in from. I've manually bleed. Used a power bleeder. Bench bleed. Gravity bleed. You name it I bleed the crap out of it. So I keep getting suspicions of the new driver rear wheel cyl cause I keep getting air from it. Then I took the time to replace all the rear line system (cause it's old anyway what's it gonna hurt). So then I power bleed it again. Now I'm getting air from the new pass wheel cylinder. I'm wondering if I should bypass the proportioning valve under the fire wall. If so would it be OK to leave it bypassed. And I think I already know this but just in case, is it possible to have an air leak in the front brake system but be able to pull it to the rear system with all of the bleeding procedures I mentioned above minus the gravity one lol. Only reason I ask is cause they are both connected via master. And thought maybe my old and new ones could have a bad spot allowing for it. Idk just thinking to much I guess.
So what are your thoughts/ideas. Maybe someone has had a similar issue with all the new parts.
Rear shoes (all)
Rear drum hardware (all)
Wheel cylinder (all)
Front pads (all)
Master cylinder (new)
Booster (reman)
Full Rear line replacement from master to both rear wheel cyl (w/correct fittings)
So I put the new master, booster, and lines in only through different stages of massive aggrevation trying to guess where my air is coming in from. I've manually bleed. Used a power bleeder. Bench bleed. Gravity bleed. You name it I bleed the crap out of it. So I keep getting suspicions of the new driver rear wheel cyl cause I keep getting air from it. Then I took the time to replace all the rear line system (cause it's old anyway what's it gonna hurt). So then I power bleed it again. Now I'm getting air from the new pass wheel cylinder. I'm wondering if I should bypass the proportioning valve under the fire wall. If so would it be OK to leave it bypassed. And I think I already know this but just in case, is it possible to have an air leak in the front brake system but be able to pull it to the rear system with all of the bleeding procedures I mentioned above minus the gravity one lol. Only reason I ask is cause they are both connected via master. And thought maybe my old and new ones could have a bad spot allowing for it. Idk just thinking to much I guess.
So what are your thoughts/ideas. Maybe someone has had a similar issue with all the new parts.