Trouble bleeding brakes

Pat, you remind me I should bleed the fluid out of the rear calipers! Related to your current issue, I just replaced both front calipers as part of my Axle Upgrade Project. I first removed fluid down to the bottom of the master cylinder reservoir, then filled, then bled front brakes only.
Like you, the pedal firmed up. Like you, the HydroBoost was loud once I started the engine. I also shut back down and bled the calipers again. H-B still seemed weird. So I put the wheels back on and tried backing/stopping and forward/stopping. Seemed fine, so I drove it. I had upgraded from 2002 brakes to 2012 brakes and immediately found the pedal was OK and the braking was excellent.
So can you make a couple controlled short moves/stops and see how it's acting? Then a short test drive? I suspect you'll be OK. Seems to me we don't realize the racket the H-B makes when the coach isn't moving and all we do is focus on the noise.

Stefonius wrote:
I don't know if your E450 is like my F450, but I had the same issue after I replaced a rotted steel brake line in the rear of the truck. In order to get a proper and thorough brake bleed on my truck, the ABS pump has to be cycled during the process... one valve at a time. This requires a scan tool capable of sending commands to the pump. Since I don't have the cash for such a tool, I have to go to the local dealership for a brake bleed.

OUCH! i hope not! i never let the fluid level go too low in the reservoir, so i hope i don't have to go thru that....but we'll see!

hotrodln wrote:

ron.dittmer wrote:
I would try bleeding again, but I would first suck out all the fluid from the master cylinder reservoir. While sucking, move the hose around the bottom-most of the reservoir to suck out all dirt and impurities. I don't recall if you can, but if possible, wipe out the reservoir with a clean shop towel once empty. Then refill and re-bleed.
I commend you and encourage you to do your own brake work. No auto shop will be as careful and determined as you to get your brakes just right. Of coarse, be sure you are doing it right to begin with. We are here to help in any way we can.

Yeah the reservoir is soooo clean now that you have to open the top to see the fluid....i'm kinda of a nut for clean brake fluid....i take some of my cars to open track days where we race the pee out of them....if i don't have proof that my brake fluid was completely swapped out in the last two months, i don't go out on track! I think most people dont pay much attention to brake fluid....but it gets very contaminated....

It sounds like you have a good handle on the brake fluid. Please let us know what you learn in the end. You have my curiosity. :)

I don't know if your E450 is like my F450, but I had the same issue after I replaced a rotted steel brake line in the rear of the truck. In order to get a proper and thorough brake bleed on my truck, the ABS pump has to be cycled during the process... one valve at a time. This requires a scan tool capable of sending commands to the pump. Since I don't have the cash for such a tool, I have to go to the local dealership for a brake bleed.

ron.dittmer wrote:
I would try bleeding again, but I would first suck out all the fluid from the master cylinder reservoir. While sucking, move the hose around the bottom-most of the reservoir to suck out all dirt and impurities. I don't recall if you can, but if possible, wipe out the reservoir with a clean shop towel once empty. Then refill and re-bleed.
I commend you and encourage you to do your own brake work. No auto shop will be as careful and determined as you to get your brakes just right. Of coarse, be sure you are doing it right to begin with. We are here to help in any way we can.

Yeah the reservoir is soooo clean now that you have to open the top to see the fluid....i'm kinda of a nut for clean brake fluid....i take some of my cars to open track days where we race the pee out of them....if i don't have proof that my brake fluid was completely swapped out in the last two months, i don't go out on track! I think most people dont pay much attention to brake fluid....but it gets very contaminated....

Boy Pat, that is a tough call. I am not familiar with hydro-boost. I assume you made sure there is enough fluid in the boost reservoir.

I would try bleeding again, but I would first suck out all the fluid from the master cylinder reservoir. While sucking, move the hose around the bottom-most of the reservoir to suck out all dirt and impurities. I don't recall if you can, but if possible, wipe out the reservoir with a clean shop towel once empty. Then refill and re-bleed.

As stated by Turbo Diesel Dude, always bleed from the farthest wheel first which is right-rear, then left-rear, then right-front, then left-front.

I commend you and encourage you to do your own brake work. No auto shop will be as careful and determined as you to get your brakes just right. Of coarse, be sure you are doing it right to begin with. We are here to help in any way we can.

Turbo Diesel Dude wrote:
start at the farthest wheel cylinder and end up at the closest to the master cylinder. JMHO

so you think it's just a matter of bleeding them better? nothing to do with the hydroboost system? I had read something about the hydroboost system storing some fluid under pressure in case you lost boost?? I don't know if this has anything to do with it or not. I bought a power bleeder that i plan to try this weekend.

My mech flushed all the old fluid, inspected the rear and front pads and shoes and readjusted the brakes for 100.00. for that amt. it was worth it to me to have a professional do mine...brakes is something a nonpro. should fool with..Btw my brakes are good as new

start at the farthest wheel cylinder and end up at the closest to the master cylinder. JMHO