Floppy brake peddle

Tiny
JUSTAGIRL65
  • MEMBER
  • 2003 JEEP WRANGLER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 131,000 MILES
Replaced booster and master cylinder. Bled them three times and still floppy?
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Wednesday, April 13th, 2011 AT 1:18 AM

15 Replies

Tiny
JIS001
  • EXPERT
Did you bench bleed the master before you installed it?
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Wednesday, April 13th, 2011 AT 1:20 AM
Tiny
RASMATAZ
  • MEMBER
--Describe what you meant by floppy
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Wednesday, April 13th, 2011 AT 1:20 AM
Tiny
JUSTAGIRL65
  • MEMBER
Yes, I bench bled the master and put two different boosters in because the first one was bunk and you could hear the pressure escaping. The pedal is stiff when the jeep is off but when you start it, it gets all loose and it has to go almost to the floor before starting to stop.
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Wednesday, April 13th, 2011 AT 2:04 AM
Tiny
CJ MEDEVAC
  • EXPERT
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, BY MY PINCHING, but 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 used!)

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

IS THIS WHAT YOU DID?

IF YOU WANT, I WILL FIND YOU A PROPER BRAKE BLEEDING VIDEO.

WE JUST WANT TO MAKE SURE YOU ARE DOING THINGS RIGHT....DON'T WANNA READ ABOUT Justagirl65 IN THE NEWSPAPER.

YOUR TURN

THE MEDIC
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Wednesday, April 13th, 2011 AT 3:04 AM
Tiny
JUSTAGIRL65
  • MEMBER
Bled the master on my work bench and then attached it to the booster and then bled the brakes with two people. I made sure I used the clip to attach the hoses to the master. Even though my Daddy swore by break fluid as a cure all, I still don't like to wear the stuff. I watched your video and I think it is very proper. The booster throws me.
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Wednesday, April 13th, 2011 AT 5:56 AM
Tiny
CJ MEDEVAC
  • EXPERT
This is the basic 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 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 SATISFIED

YOU SHOULD HAVE THE DRUM BRAKES ALREADY ADJUSTED, BEFORE YOU DO THE BLEEDING PROCEDURE.

I HAVE SEEN DUMMIES BREAK OPEN THE BLEEDERS AND JUST START PUMPING AWAY. NOT GOOD!

YOUR TURN

THE MEDIC
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Wednesday, April 13th, 2011 AT 4:13 PM
Tiny
JUSTAGIRL65
  • MEMBER
So, you think it's a bleeding problem. What about the proportioning valve would that have anything to do with it? Because there is not a single bubble in the lines.
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Thursday, April 14th, 2011 AT 12:15 AM
Tiny
CJ MEDEVAC
  • EXPERT
RASMATAZ, RASMATAZ THIS IS CJ MEDEVAC, OVER

I HAVE PREPPED THE TARGET

LAST SHOT (OUT OF AMMO)---IS THERE AN ADJUSTMENT BETWEEN THE MASTER CYLINDER AND THE BOOSTER?

I HAVE POURED OVER "MITCHELL 1" (LONG TIME G.I!), CANNOT FIND ANY "NORMAL" ANSWER TO THIS. (HARD TO NAVIGATE IN THERE TOO)

POPPING SMOKE NOW!

I'LL BE AT THE PZ

SEND IN FRESH TROOPS!

THE MEDIC--OUT
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Thursday, April 14th, 2011 AT 1:49 AM
Tiny
JUSTAGIRL65
  • MEMBER
No, there is no adjustment. This is why we are stumped. Maybe it just needs a little Viagra. Thanks for your help
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Thursday, April 14th, 2011 AT 3:54 AM
Tiny
JIS001
  • EXPERT
You could have a defective master cylinder?Have you checked for any external leaks in the lines and calipers to see if you are losing pressure there? Also have you checked the caliper slid pins? Make sure the caliper slides back and forth freelly. You can remove them and lube them. So make sure those calipers slide freelly. Also have you checked for air in the ABS hydraulic pump unit? Make sure you bleed there as well.
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Saturday, April 16th, 2011 AT 2:47 AM
Tiny
JUSTAGIRL65
  • MEMBER
We are moving along to the calipers today. If there was a pressure leak some where along the lines, wouldn't there be air when they where bled? I don't have ABS on my '03.
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Saturday, April 16th, 2011 AT 2:54 PM
Tiny
JIS001
  • EXPERT
What did you find with the calipers? Can they slide freely? What about leaks? Are the pistons dry and hoses free from any leaks? If all that is good, I would say your new master cylinder is defective?
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Monday, April 18th, 2011 AT 2:35 AM
Tiny
JUSTAGIRL65
  • MEMBER
They were pretty worn and the drivers side had a small leak so small I almost missed it. We went ahead and replaced both. Peddle is still a bit soft but it helped. I think we are so used to the ABS on the Chevy that we are just nit picking it to death. At least it got a new break system out of the deal. I asked the other guy if it could be the proportioning valve, does it have any thing to do with anything?
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Wednesday, April 20th, 2011 AT 1:31 AM
Tiny
JIS001
  • EXPERT
No I do not believe it really has anything to do with a spongy pedal? The proportioning valve is used in the rear to decrease the rate of pressure rise to the drums relative to the pedal force as weight is shifted to the front during braking. This prevents the rear from locking up under hard braking conditions assuming you have drums in the back. I believe you have actually narrowed it down to the leaking calipers. You may still want to try and bleed the lines at the master cylinder to see if it will improve? But you are correct on trying to compare your Chevy to a Jeep? They are both different? I had a Mercury Sable once and that pedal was really soft. My wife drove it one day and thought I had a problem but it was really normal? It is hard to say that about your Jeep since I am not the one driving it? Whoever is the daily driver should feel if it is much batter or not? But sometimes you get a little nervouse you feel the pedal is still going low after this experiance so a second opinion wouldnt hurt either? But like I mentioned earlier, I do believe you found the root cause of your failure and I am glad to see you saw the positive side of the deal which you do have new calipers now with a master cylinder. Thanks for using the site and I hope we can help you again in if you need assistance.
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Wednesday, April 20th, 2011 AT 2:47 AM
Tiny
JUSTAGIRL65
  • MEMBER
The jeep is finally paid off now and we are going to put the payments back into it for a year. I live in a rural area and it has been through "***" and back. So we will surely be using this site. Thank you so much.
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Thursday, April 21st, 2011 AT 2:47 AM

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