Mechanics

CJ BRAKE PROBLEM

1980 Jeep CJ7 • 5 miles

CJ Medic,

I have a 1980 CJ7 with a brake problem, I have performed the following:

New wheel cylinders, drums, shoes, hardware kits, master cylinder, (shimmed master cylinder out 3/8 inch to shorten pushrod), new calipers. Also, took it to a professional shop to fix, they eventually called me and gave up on it.

My problem is brakes take two pumps to build up a pedal, the first one goes to the floor. Once the pedal is built it seems to be solid (not spongy).

We have bled the system countless times including gravity bleeding and bench bled the master cylinder.

Jeep has over axle lift kit with brake line extensions.

Thanks
Adam
Avatar
Adamsjeep
July 29, 2012.




Ok. Dumb question: Have you made sure the bleeder screws were fully tight before letting off the pedal, or used a bottle of clean fluid to make sure no air gets back into the system?

Are you losing brake fluid at all?

Have someone pump the brake pedal while you observe the hoses. Do they appear to be bulging? If so, replace them.

Why did you shim the master to shorten the push rod? Do you have the correct push rod and master?

Another dumb question: Did you hook the lines up properly?

Is it vacuum-assisted?


Rivermikerat
Jul 29, 2012.
1ST AND FOREMOST THANK YOU FOR THE RECOGNITION!

GRAVITY BLEEDING IS SORTA INEFFECTIVE, ESPECIALLY WITH LOOPS AND SAGS IN THE BRAKE LINES AND HOSES. IF THERE IS AIR IN IT--IT WILL ALWAYS FLOAT TO THE TOP OF YOUR LINES AS THE JUICE GOES ON BY....SORTA LIKE TURNING YOUR SHAMPOO BOTTLE UPSIDE DOWN

I WILL SOON MAKE SOME BETTER PICS ON BENCH BLEEDING USING THE TUBES (SORRY I DON'T HAVE THEM YET...I MAKE 'EM AS I DO STUFF TO MINE OR SOMEONE ELSE'S)

MY METHOD IS DONE WITH THE MASTER CYLINDER INSTALLED ON THE JEEP AND USING 2 PEOPLE, THIS IS SORTA SIMILAR TO THE VIDEO YOU WILL SEE, MADE BY SOMEONE ELSE

THE WAY I WAS TAUGHT---USES TWO PEOPLE---THE PROCESS IS EXPLAINED SHORT AND SWEET, BUT IS REPEATED MAYBE 6 TO 8 TIMES PER WHEEL, JUST TO BE SURE.....HERE IT IS BELOW (I COPIED MY ANSWER TO A FORD TRUCK)

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. Kinda a "string" hose clamp

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--the air going back and forth in the tubes....My way makes things faster--the air and fluid only go one way....out!, 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

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

xbleeding

This is the basic bleeding procedure I use:

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"

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.

BRAKE JUICE IS WATER SOLUBLE---SO IT SHOULD RINSE OFF OF THE BACK OF YOUR WHEELS AND THE DRIVEWAY REALLY EZ

Questions?....I hope not!

PLEASE REPLY WITH A BIG OLE GRIN!

THE MEDIC

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Tiny
CJ MEDEVAC
Jul 30, 2012.
And there's our lovable Jeep specialist.

Hey CJ, I made it to Brazil finally.


Rivermikerat
Jul 30, 2012.
STAYIN'. OR JUST A VISIT?

THE MEDIC


Tiny
CJ MEDEVAC
Jul 30, 2012.
Stayin. Except for visits. I'm hoping to hit Daytona for the race in February. But I may have to choose between that and Disneyworld for all of us next July.


Rivermikerat
Jul 30, 2012.
ALL-RIGHTY THEN. Adamsjeep

LET'S HEAR AN UPDATE

I KNOW YOU HAVE BEEN READING SOME OF MY STUFF, SO YOU SHOULD KNOW

I DO LIKE TO SEE PICS OF THE JEEP WE ARE WORKING ON

I REALLY HOPE YOU AIN'T SORTA SCREW UP THE PROPORTIONING VALVE, NOT SAYING ONE COULD NOT GO BAD, I HAVE NEVER SEEN A BAD ONE WITH AS MANY AS I HAVE WORKED ON, NOR HEARD THAT ONE HAS GONE BAD. THAT DOES SEEM TO BE THE 1ST POSSIBILITY BLURTED OUT, WHEN SOMEONE HAS PROBLEMS WITH THEIR BRAKES THAT THE CANNOT FIGURE OUT. THE ALL TIME WINNER FOR A "I DON'T KNOW WHAT'S WRONG WITH MY RIG IS: "I THINK IT'S VAPOR LOCKING"

OK BOSS

ARE YOU NOW ABLE TO STOP ON A DIME. LIKE THIS TREE FROG WHO WAS STUCK ON THE FRONT DOOR

YOUR TURN

THE MEDIC


Tiny
CJ MEDEVAC
Jul 31, 2012.

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