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jhidrogo

Air Trapped In The ABS Block?

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Ok so the other day i took my 01 2500 apart to install new ball joints. I took the brake lines off the calipers to give myself more room to work and when i went to reinstall everything went smoothly. I bled the lines i have full pressure coming from all 4 calipers. I cannot get any foot pressure. I tryed a "new/used" Hydroboost and it was not the problem. I am out of ideas and cannot get the pedal to hold pressure. I start it and try to move it doesnt grab till the very bottom and not to much. `:( :confused: I think there could be air trapped in the abs sensor? I have no idea any help would be great. Thanks in Advance!!!!!!!

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Its possible you got a air bubble hung up in the ABS pump pump. Or the other fact you might of lost your master cylinder on the brakes. I've been told that if you don't normally bleed you brakes it could damge the MC seals internal when you push it to the floor being the bore now is rough from debris that is normally not touch in normal operation throw...So at any rate if the pedal is building pressure then you got a leak internally. Typically master cylinder...

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I tryed another master cylinder. That didnt work. Could it be the abs block that is not allowing enough preassure? they have very little and they lock up. the abs and brake light are on in the dash.

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Use the old clear plastic tube and let it drain for a while. Get you a clear jar and put a little fluid in the bottom so it dont suck air and just keep the fluid level full. Oh pump brakes if you want or just let gravity do the job. :smart I heard someone tell me that once, oh by the way check is in the mail. :thumbsup

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I tryed another master cylinder. That didnt work. Could it be the abs block that is not allowing enough preassure? they have very little and they lock up. the abs and brake light are on in the dash.

Oh... This changes everything...

http://mopar.mopar1973man.com/cummins/2ndgen24v/abs/abs.htm

Use the old clear plastic tube and let it drain for a while. Get you a clear jar and put a little fluid in the bottom so it dont suck air and just keep the fluid level full. Oh pump brakes if you want or just let gravity do the job. :smart I heard someone tell me that once, oh by the way check is in the mail. :thumbsup

Oh you mean like this...

Posted Image

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The fluid starts dark, when the tube clears up - the color of new fluid - you should not have air. If the lines have drained - more work.Damaged chevrons can often be proved to R&R a MC by hitting the pedal fast so the damaged chevron inflates to seal.Pumping from the wheels with 20# or so of pressure is very effective for those systems that are resistant. Use a new, clean bleeder screw to pump in with - you do not want the dirt and oil from the underside inside the brake system, They are hard to keep clean when your hands are dirty with oil/grease. If the MC is not level or front down the will be very difficult but will be easy if set front down to reverse pressure bleed. Same with ABS, make it level, by the way it is parked or unbolt it and bend the lines a little to get level.Air bubbles in upward loops of tube will not gravity bleed and can be hard to vacuum bleed but will pressure bleed well at over 40# and reverse pressure at 20#.That is for a shop - if you are out and need an alternative - do the gravity bleed and then bump the pedal 1/2 the way down (fast as possible) and then let the caliper/cylinder gravity the air sucked back out of the system. It may take 3 times or more to clean up but most times 2 tries will get enought pedal to drive it back to the shop. And if you are in the woods water will work to get it back and if the water is removed same day it is no problem. If it is coldenough to cause a hard water problem coolant will also work - just harder to clean out. keydl

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