Bleeding brake job from hell !
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Elder User
Joined: Dec 2006
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From: Kitchener,Ontario,Canada
Bleeding brake job from hell !
O.K. heres the scoop. I had a leaking proportional valve & low brake pedal., So after getting the low down on what this valve does, I decided to replace the prop valve with a used one. Looked in good shape, had not been leaking, so decided to fit it on & bleed the system & see what happens.
Well today I spent most of it trying to get out the air. Pedal is solid until you start up the engine & use the booster. Then it sinks & if I bleed again there is still air in the system, I've run best part of a litre through all 4 lines starting longest thru' shortest. Then I decided to look in the 3/4" end cap of the prop valve where the spring & plunger is & the neoprene cap. Not much oil in there but some blackish goop I'd say less than a teaspoon , should this area not be full of brake fluid ? The small "O" ring is torn up so I'll replace that, the plunger serrated seal looks fine.
So my question is how do I get ALL the air out the brake system ?
Will I have to bleed the master cylinder & the proportional valve ? if so whats the best way to do it ?
Hopefully I can nail this down tomorrow with a bit of help from you guys!!
Well today I spent most of it trying to get out the air. Pedal is solid until you start up the engine & use the booster. Then it sinks & if I bleed again there is still air in the system, I've run best part of a litre through all 4 lines starting longest thru' shortest. Then I decided to look in the 3/4" end cap of the prop valve where the spring & plunger is & the neoprene cap. Not much oil in there but some blackish goop I'd say less than a teaspoon , should this area not be full of brake fluid ? The small "O" ring is torn up so I'll replace that, the plunger serrated seal looks fine.
So my question is how do I get ALL the air out the brake system ?
Will I have to bleed the master cylinder & the proportional valve ? if so whats the best way to do it ?
Hopefully I can nail this down tomorrow with a bit of help from you guys!!
Posting Guru
Joined: Jul 2004
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From: Mitchell, SD
Search my friend....
Originally Posted by Aerocolorado
Tips on bleeding: Get plently of fluid and an assistant. Do NOT depress the brake pedal all the way to the floor when bleeding, halfway is sufficient. (The reason for only halfway is due to the design of these master cylinders.) Do one brake line at a time, starting with the furthest from the master cylinder.
More than likely, you will find the bleeder screws on the rear cylinders rusted tight. Judicious application of PB Blaster, WD-40, or other solvent several days beforehand may ease the removal. Even so, be prepared for the bleeder to break off. You may want to just consider purchasing two new cylinders and change them out. The cost is fairly minimal and saves much aggravation if those bleeder screws are permanently bonded.
Do not run the master cylinder dry or you will get air in the system. If air gets into the RABS valve, it is difficult to express. Also, be prepared for the RABS warning lights to come after doing this procedure - very common occurence.
More than likely, you will find the bleeder screws on the rear cylinders rusted tight. Judicious application of PB Blaster, WD-40, or other solvent several days beforehand may ease the removal. Even so, be prepared for the bleeder to break off. You may want to just consider purchasing two new cylinders and change them out. The cost is fairly minimal and saves much aggravation if those bleeder screws are permanently bonded.
Do not run the master cylinder dry or you will get air in the system. If air gets into the RABS valve, it is difficult to express. Also, be prepared for the RABS warning lights to come after doing this procedure - very common occurence.
BTW the RABS is a PIA to bleed, if you have not already figured out.
Originally Posted by 96_4wdr
I've had good luck flushing and bleeding the Aero by myself....start by sucking out old fluid from MC with turkey baster and flush/bleed MC first from outlet fitting...then the proportioning valve, both end fittings...next are lines/brakes...Ford service manual for Aero RABS says RR first...neoprene line on bleeder **** into clear bottle container...pump until clear BF out into bottle...Ford sequence RR, LF, LR, RF...remove bleeder completely...clean end of bleeder-corrosion and put a light coating of silicone dielectric grease on threads only...do not overtighten bleeder when done...just snug
Krank, easy to do and good results even by one person...no more RABS problems/lighs and best brakes I've had since new...
I had no success and could not clear the RABS light even after cleaning the prop. valve switch until I found and followed Ford's mandatory flush/bleed wheel sequence
Krank, easy to do and good results even by one person...no more RABS problems/lighs and best brakes I've had since new...
I had no success and could not clear the RABS light even after cleaning the prop. valve switch until I found and followed Ford's mandatory flush/bleed wheel sequence
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Elder User
Joined: Dec 2006
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From: Kitchener,Ontario,Canada
I've gotta make one of those pressure bleeder's !
Looks like I don't have to worry about the prop valve or the RABS unit. However it would be easy enough to crack open gently the flare nuts with this pressure system attached.
I have the sprayer already (wife HAD one)
, just need another MC cap & a 1/4" hose fitting.
Aeroman.
Looks like I don't have to worry about the prop valve or the RABS unit. However it would be easy enough to crack open gently the flare nuts with this pressure system attached.
I have the sprayer already (wife HAD one)
, just need another MC cap & a 1/4" hose fitting.Aeroman.
Lead Driver
Joined: May 2003
Posts: 9,303
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From: Lyndonville, Vermont
I've had the 94 and 96 systems empty and just let them self bleed after a few pumps. The only time I had issues was a leak or rear brakes not adj. Absolutely no trouble bleeding..maybe I'm lucky
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Elder User
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From: Kitchener,Ontario,Canada
Glad thats done!
Well the job is done as far as there seems to be no air in the system. Went round again this morning bled the Prop valve (two MC feed pipes) & then all wheel cylinders as per Ford sequence. Pedal feels rock hard until you start the engine & use the booster. Maybe that is normal? If you shove REAL hard with engine on, you can get it down, but this is with quite a lot of pressure for that to happen.
Nothing leaking, but I'll obviously keep my eye on the MC reservoir for a week or two.
Really was not a bad job, but time consuming, since I also decided that it would be much better with all 4 wheels off & then my son decided it was time to put on his summer tires, so we got a bit mixed up with the whereabouts of the sockets etc.
Aeroman cheers!
P.S you'll have to add in the beer ***** sound!
Nothing leaking, but I'll obviously keep my eye on the MC reservoir for a week or two.
Really was not a bad job, but time consuming, since I also decided that it would be much better with all 4 wheels off & then my son decided it was time to put on his summer tires, so we got a bit mixed up with the whereabouts of the sockets etc.
Aeroman
cheers!P.S you'll have to add in the beer ***** sound!
