What's up with my brakes?

[porkchop]

Ok this is really starting to boggle my mind. I have just got done putting in the whole brake system from a '79 cherokee and I can not for the life of me get my brakes to work. This is what I have, I have fluid all the way to the back brakes and I have bled them until there is no air in the lines (as far as I can tell). I have removed the proportioning valve and cleaned it, while I am bleeding the brakes I am keeping the metering valve open. After all this I can still not get pressure on the pedal and the brakes just do not work. I even replaced the rubber gromet for the check valve on the vacum booster. What could it be? The wag does not need to be running for the booster to work does it? I have been bleeding brakes since I could reach the pedals and this is the first time that I have come across this problem Any help from the brake experts. Thanks.

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'67/'79 Wagoneer mix
Body of a 33 year old
Heart and legs of a 21 year old.
360,TH400,QT,D44's F&R
32X11.50's

"I regret that I have but only one paycheck to give to my Jeep."

[ClarkGriswald]

The wag does not need to be running for the booster to work does it?
(Isn't the booster running off of vaccum?)

Yes.. there is no vaccum source when the engine is not running.
You are far my jeep knowledge superior I would think you would know this? Ive never done this thing with the metering valve, Ive heard of it. but have bled the brakes on lots of stuff and never messed with the prop valve unless I was replacing lines and took it off to clean and prepare it for reasembly with the new lines.. so this metering valve.. is it what does the different ratio of pressure to the front\back? I dont know what the answer to your question is I guess but am confused as to what it means to open that valve while bleeding.. never done that on any vehicle before. (honestly wouldnt mind an answer to this myself, Ive always had good result's but if there is something to this I would love to know the truth.. )(P.S. Ive never had the engine running while bleeding brakes either. just have a guy step on the pedal then I open the bleeder and a bunch of air\fluid shoots out.. when it stops i close the bleeder and have the guy let off the pedal. a few times on each side starting with the farthest point from the master cylinder usually gets all the air out and makes em work just fine... once again just a humble novice.. hope this helps. the back brakes usually are responsible for most of your "pedal" although the fronts do most of the work..cause i think they try to make the back kick in sooner to make up for the fact that the front axle does most of the work braking.. so they will wear more evenly. othewise if they were even your back brakes would never get a chance to work cause the fronts would be doin most of the braking. Is this right? its just what I have put togethor over the years from experience.. I wouldnt mind people bitc*ing me out cause I am totally off base If it ends up educating me or others..

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88 Grand Wagoneer
D44's front\rear
AMC 360
TF 727
NP 229 (Funky)
Bone Stock (for now)
NO RUNNING BOARDS!

[River Beast]

From what I understand of the metering valve or by another name... proportiong valve is just that... distributes the evenly between rear drums and front disks. I believe Porkchop is in the right. There is a nipple on the side of the valve to relieve the pressure of the valve for bleeding. However... I have only done this once due to a brake PROBLEM. I was told that inside the valve is a slide type of plunger that regulates the pressure. If this were to be offset to one side of the valve or the other, the brakes would not work properly. that was my case on a previous rig. After bleeding with the nipple depressed, my probelems went away as did my idiot light when the brake was depressed. Yes, I tried bleeding the conventional way and no success until I depressed the nipple during bleeding. Maybe it was just luck... I don't know...As Clark stated... if I am wrong make me smarter along with the rest of us that need to know for future reference.

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TJ
78 Wagoneer "River Beast"
360/TH400/QT
Dana 44's (soon to be 4.88's)
7" SOA conversion
4" Skyjacker Softride
3" Trailmaster Bodylift
33x12.50's on 15x10's
(soon 38.5x14.50's on 12's)
My FSJ site: http://www.geocities.com/~spazz4life
"Where there's a hill...there's a way!"

[porkchop]

The metering valve is on the front of the proportioning valve. It does what you have been saying, it opens the prop valve so it delievers equal pressure to the front and back distribute the fluid evenly. When it is closed the front brakes get more of the power than the back, since it takes more pressure to work front discs than rear drums.

So why won't my brakes work?

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'67/'79 Wagoneer mix
Body of a 33 year old
Heart and legs of a 21 year old.
360,TH400,QT,D44's F&R
32X11.50's

"I regret that I have but only one paycheck to give to my Jeep."

[ClarkGriswald]

do you have a good rubber gasket under the lid on the master cylinder?? sometimes you can hear em leaking when theyre bad.. just an idea

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88 Grand Wagoneer
D44's front\rear
AMC 360
TF 727
NP 229 (Funky)
Bone Stock (for now)
NO RUNNING BOARDS!

[River Beast]

Hey... just thought of something... have you ever heard of back bleeding??? I did this once with a friend. You force the brake fluid thru the bleeder valves using a oil can, pump style with a rubber tube. No pumping the brake required, but takes to people... one to pump and the other to watch the master cylinder. Makes a mess but for what it's worth pushing air "down" thru the lines is much harder than pushing it "up" thru the master cylinder. It works...if that's the ONLY problem... just a thought.

Reason I mention this... my friend had a serious problem with air in the lines after he broke the system open. Bled 2 qts thru the whole system and still no brakes!! Once we back bled the system, all the air came thru the master cylinder and all was well. Took some time but worth it to have brakes.

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TJ
78 Wagoneer "River Beast"
360/TH400/QT
Dana 44's (soon to be 4.88's)
7" SOA conversion
4" Skyjacker Softride
3" Trailmaster Bodylift
33x12.50's on 15x10's
(soon 38.5x14.50's on 12's)
My FSJ site: http://www.geocities.com/~spazz4life
"Where there's a hill...there's a way!"

[andy d]

i've got a similar problem with a bmw i'm playing with. when engine is running brake pedal mushes to floor. the car's hydraulic clutch uses master cyls reservoir.clutch master was shot. i think po ran reservoir dry getting air into abs. back bleeding eh? what didja use for a pump RB?

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'88 gwag

[porkchop]

I have brakes!!!! I am not sure what I did but I have brakes now. I went out looked everything over and I now have brakes. I am happy about this as you can tell. I do Have another problem though, read my new post. Thanks for all the ideas and help. Lets see if you all can do it again I should dedicate my jeep to all of you!

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'67/'79 Wagoneer mix
Body of a 33 year old
Heart and legs of a 21 year old.
360,TH400,QT,D44's F&R
32X11.50's

"I regret that I have but only one paycheck to give to my Jeep."