Brake Issue

Brakes work fine going forward. Go in reverse, brakes are soft. Once I put it in drive, I have to pump the brakes a couple of times. The first "pump" is pedal is on the floor, the second pump and the brakes are still soft, about half way to floor. After that, the brakes feel normal. Any suggestions/ideas on the problem? I changed the left rear caliper about a year ago, this started around May.

Sounds like your brake booster is going. Not hard to replace.

PDEVVOLTAR said:

Brakes work fine going forward. Go in reverse, brakes are soft. Once I put it in drive, I have to pump the brakes a couple of times. The first "pump" is pedal is on the floor, the second pump and the brakes are still soft, about half way to floor. After that, the brakes feel normal. Any suggestions/ideas on the problem? I changed the left rear caliper about a year ago, this started around May.

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Agreed, sounds like booster.

I did mine when i bought the jeep, just gotta remove the master cylinder, pull off the vacuum lines from the booster and unbolt it from the inside of the car by the brake pedal. then shimmy new one in, bolt down, re-attach brake pedal, re-attach master cylinder and vacuum lines, then re bleed the system.

MarksmanAkula said:

Agreed, sounds like booster.

I did mine when i bought the jeep, just gotta remove the master cylinder, pull off the vacuum lines from the booster and unbolt it from the inside of the car by the brake pedal. then shimmy new one in, bolt down, re-attach brake pedal, re-attach master cylinder and vacuum lines, then re bleed the system.

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Thanks for the suggestion. That's what I was thinking.

What year and does it have ABS etc
Don't go jumping at master cylinder right away
Also bad rubber hoses will also do that at times if they are going bad inside

Helps a ton if everyone would add year, etc , a lot of these questions require knowing the year etc

tommudd said:

What year and does it have ABS etc
Don't go jumping at master cylinder right away
Also bad rubber hoses will also do that at times if they are going bad inside

Helps a ton if everyone would add year, etc , a lot of these questions require knowing the year etc

Click to expand...

2006. Had it looked at for alignment, different issue. Mechanic said it needs right front hub. It could be the cause.

Hub will not cause a brake issue like that

tommudd said:

Hub will not cause a brake issue like that

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Thanks. I will check the cylinder

LOL, oh well ...........................

Check the vacuum line going to the Brake Booster.

The gasser has a rubber hose going from the intake manifold which then splits up...one hose goes to the Brake Booster and the other side goes into the cabin to control the air vents.

The CRD has a seperate vacuum pump for the vacuum...likewise the hose splits up to the Brake Booster and to inside the cabin.

Make sure these hoses are not damaged and are firmly connected.

A bad booster can under no circumstances cause the pedal to go to the floor. All it does is add assistance for pushing on the master cylinder.

Since you have a 2006, you have ABS. It could be a bad master cylinder, ABS, or air in the system. Master Cylinders are cheap and somewhat easy to install. You 'should' activate the ABS after installing one to insure no air is trapped in the ABS.

Well then the KJs have a newer brake booster system than what I am used to!

Used to test brake boosters by pressing firmly on the brake pedal with engine OFF. Start the engine and the pedal should drop under your foot by about one inch then be firm.

If the pedal continues nearly all the way to the floor then the booster is bad.

This is my experience with non-ABS systems which obviously are more complex.