Mechanics

JEEP TJ BRAKES PROBLEM

2000 Jeep TJ • 13,000 miles

I changed the master cylinder on 2000 wrangler in the process of changing the mc I noticed brake fluid in brake booster but I continued putting mc on I bench bled the mc I bled all 4 wheels very good started vehicle brake light comes on and brakes are spongy and go to the floor while vehicle is running I pinch off vacuum line to brake booster the brake light goes and peddle comes to the top and got hard pessure but brakes grabbing very little and peddle hard to push down I then unpinch hose to the brake booster and brake light comes back on and peddle goes to the floor is the brake booster bad or is the porportion vavle bad and this vehicle does NOT have abs please help I will make a nice donation if you help trust me thanks
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1fitter
January 21, 2013.




Are there any leaks in the system? As far as the brake booster, it sounds like it is working. The proportioning valve rarely go bad. I think you either have air in the system yet or you got a bad MC. When you bled the brakes, did you start from the right rear and then work your way to the closest wheel to the MC?


Yes I did about 7 times got great straight fluid at all 4 the mc is working I bled the brakes very good I went through 2 quarts of fluid with the brake fluid inside of the booster can that make diaphrams or seals go bad


Tiny
1fitter
Jan 21, 2013.
I don't think the booster is bad. Its function is to make it easier to press the brakes. It is doing that to the extent that the pedal goes to the floor. If there are no leaks and the rubber brake hoses are not expanding, it sounds like a bad MC. Did the old one do the same thing?


Yes kinda this is the 2nd mc I put the first 1 on and bench bled it bled all 4 but could not get any peddle what so ever so pulled 1st mc off took it back put 2nd mc on bench bled it bled all 4 wheels this time was starting to get pedal after going around bleeding at all 4 peddle came right up but when you start the vehicle the brakes get soft and the pedal goes to the floor I pinch the hose off and the pedal comes up and holds but still not stopping by all this can I eliminate the brake booster out of the problem and the hoses and rest of system is tight


Tiny
1fitter
Jan 21, 2013.
I don't think there is a problem with the booster. There is another guy that works just on Jeeps. I will talk with him tonight and get him to contact you. However, I feel you have a bad MC.


Thank you very much you have been great thanks
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Tiny
1fitter
Jan 21, 2013.
Glad to help.


OK---I'M HERE!

HOPE I CAN HELP

MANY TIMES THE BLEEDING PART AIN'T DONE RIGHT......GONNA THROW THIS OUT ANYWAY.....DON'T KNOW YOUR EXPERIENCE LEVEL

I NEED TO MAKE SOME PICS OF BENCH BLEEDING--ON THE VEHICLE--NOT ON A BENCH

ESPECIALLY THE PART WHERE I WIND STRING AROUND THE HOSE ON THE PLASTIC BLEEDING ADAPTERS

I JUST AIN'T HAD TO CHANGE ONE IN A WHILE WHERE MY CAMERA WAS HANDY

THIS "GRAVITY BLEED THING" I HEAR ABOUT (WHEN DOING THE WHEELS) SOMETIMES JUST DON'T WORK!

WHAT HAPPENS IS THE FLUID DOES COME ON OUT---BUT THE AIR UP THERE IN THE BENDS AND LOOPS AND SUCH KEEPS RISING----LIKE WHEN YOU TURN THE OLE "NO MORE TEARS" SHAMPOO BOTTLE UPSIDE DOWN....THEN STARE AT IT IN AWE, LIKE YOU ARE GONNA DISCOVER SOMETHING AND GET A NOBEL PRIZE!...........5 FLIPS OF THE BOTTLE IS PLENTY.....THAT'S WHERE I FINALLY GET BACK TO WASHING MY HAIR.

I'M PASTING THIS IN FROM ANOTHER POST I ANSWERED---BACK WHEN I DID NOT USE ALL CAPS

My Bench bleeding ain't on the bench...it's on the vehicle!

Much EZer that way!

This can be done on the vehicle (my preference) using two people, one pumping and one monitoring the Master Cylinder.

I wrap string loops around the little hoses and tie a knot, as to keep the tubes from blowing off of the plastic adapters.

I take it one step further, by squeezing the little hoses with my fingers (as if I were a check valve) The VERY SLOW PUMPING OF THE PEDAL will push the fluid into the reservoir, SCOOTING BY MY PINCHING, but the pinch will not allow it TO S.UCK AIR BACK, as you see in the beginning of this video....My way makes things faster, but if you did not tie the hoses to the adapters--THEY WILL BLOW LOOSE (lots of adjectives will be bust loose out of your mouth!)

This is very similar to my way.... It takes two people cause the fire wall is in the way (unlike in this video) The 2nd man must "pedal" slow and EZ during the bench bleed

http://www.youtube.com/watch?v=i3Jhbz4mVKw&feature=related

xbleeding

This is the basic bleeding procedure I use for each wheel:

KEEP FLUID IN THE RESERVOIR AT ALL TIMES/ CONSTANTLY CHECKING!

START WITH FURTHEST OUT WHEEL CYLINDER, FROM THE MASTER CYLINDER, WORKING TO THE CLOSEST (RR, LR, RF, LF)

2 PEOPLE, ONE PUMPING, OTHER BLEEDING AND REFILLING

#1 man is the Bleeder

#2 man is the Pump Man

1-MAN BREAKS BLEEDER LOOSE-SNUGS IT BACK YELLS, "PUMP IT UP"

2 MAN-PUMPS 6-8 TIMES (YELLS "PUMPING") THEN HOLDS PEDAL--YELLS, "HOLDING"......MORE PUMPING IS FRUITLESS FOR EACH OPENING OF THE BLEEDER SCREW

1-MAN CRACKS BLEEDER...AIR/ FLUID SPURTS OUT

2-MAN YELL, "FLOOR", JUST BEFORE THE PEDAL, ACTUALLY HITS THE FLOOR

1-MAN TIGHTENS THE BLEEDER....WHILE IT IS STILL SPURTING OUT (NOT AFTER IT STOPS...OR IT WILL SUCK AIR BACK IN).....THEN YELLS, "OKAY---PUMP IT UP"

PROCESS STARTS OVER UNTIL YOU ARE SATISFIED, WITH EACH WHEEL

THIS DOES NOT MATTER WHETHER THEY ARE DRUM BRAKES OR DISC.

ON DRUM BRAKES:

YOU SHOULD ALREADY HAVE THE SELF-ADJUSTERS PUSHING THE SHOES CLOSE TO THE DRUMS, SHOES SLIGHTLY TOUCHING THE DRUMS , BEFORE YOU DO THE BLEEDING PROCEDURE.....THIS WILL KEEP YOU PEDAL AT THE TOP AND TIGHT.

I PREFER THIS OVER USING THE ONE MAN, HOSE AND CUP, METHOD WHERE YOU SUBMERGE THE HOSE AND PUMP....TO ME THIS IS FASTER AND MUCH EZer.

IS THIS THE WAY YOU APPROACHED YOURS?

THE MEDIC


Tiny
CJ MEDEVAC
Jan 22, 2013.
FORGOT MY PIC!

THE MEDIC


Tiny
CJ MEDEVAC
Jan 22, 2013.
Yes that is how I bled all except for adjusting the back brakes and also tightening bleed right before the pedal hits the floor


Tiny
1fitter
Jan 22, 2013.

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