Weak Brakes? 2003 Liberty

[Jeepguy43]

Hello All,
New to this forum, but not new to Jeeps.

Anyways, I bought this 03 Liberty which is in excellent condition with 86k miles on it. The brakes felt very weak when I got it home - If you slam on them, pedal goes to the floor and it took awhile for it to stop. I coasted through a stop sign not expecting it when I got near my house (thankfully no cars coming). Anyways, I replaced all 4 rotors and pads this weekend with ceramic pads in hopes to fix the issue. The old rotors were pretty rusty and slightly glazed, but the pads were nearly new. I have a feeling the previous owner cheaped out and just replaced the pads without touching the rotors.

Anyways, it brakes much better but its still not feeling like its grabbing the way it should. If you slam on the brakes the pedal still goes to the floor and it rolls for a bit. I'm almost thinking the booster is going because I don't feel as though enough boost is being built up to give the brakes proper pressure.

Any idea's???

 

[TomO]

I think that if the pedal reaches the floor, you are not going to find the problem with the booster.

The first things I would do is to fully bleed all of the brake lines while checking each caliper for signs of leaking. I would guess that you have air in the system or the master cylinder needs new seals. I.e. you are able push the piston past the oil.

 

[Jeepguy43]

Yeah I checked the calipers yesterday and they were all bone dry and in good shape. You suspect the master cylinder? Ok, thats cheap enough and easy enough to replace.

 

[TomO]

I would bleed the system fully before replacing the master cylinder. Be sure to get new DOT-3 brake fluid all the way to each caliper before dismissing the master cylinder as faulty.

How is the fluid level in the reservoir?

 

[Jeepguy43]

Its full. I checked it after replacing the brakes and taking it for a spin. I first thought it was going to be low but it was perfect. I'll definitely bleed the first though. No sense in throwing away money.

 

[LibertyTC]

Dot 4 is what the dealers are now using.
Definitely bleed all four corners and were the old pads worn evenly?
I do not know what brand you went with but would recommend Napa, what a difference, rear brakes were in need!
I may even change the front over to Napa Premium/adaptive one pads as the front brakes (OEM) make way to much dust and lack grip, and they were replaced 10k ago.
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[Jeepguy43]

The ones I got were from Advance Auto Parts, Wearever or something along those lines. Yes the other brakes were worn evenly.

 

[tjkj2002]

Easy way to test if it's the master or the booster.

With vehicle off pump the brake pedal about 10-15 times to deplete all vacuum.Apply steedy pressure to the brake pedal(not real hard but a little more then moderate) and start the engine.The brake pedal should fall about 1"-2" and hold under the steedy pressure,if the pedal does not fall the booster is bad,if it keeps falling the master is bad.

 

[Jeepguy43]

Easy way to test if it's the master or the booster.

With vehicle off pump the brake pedal about 10-15 times to deplete all vacuum.Apply steedy pressure to the brake pedal(not real hard but a little more then moderate) and start the engine.The brake pedal should fall about 1"-2" and hold under the steedy pressure,if the pedal does not fall the booster is bad,if it keeps falling the master is bad.

Awesome advice, I'll give it a shot tonight and post back up. Thanks for the tip. I'm almost hoping its the master as it'll make bleeding the brakes more worth while.

 

[tjkj2002]

Awesome advice, I'll give it a shot tonight and post back up. Thanks for the tip. I'm almost hoping its the master as it'll make bleeding the brakes more worth while.

Oh and another thing it's a good idea to do this test twice.Once with your foot squarly on the brake pedal and the second time with your foot on the very edge of the brake pedal to make the rod push more on one side of the master pistons,helps to better find those small internal master leaks with only side load pressure.

 

[Jeepguy43]

Oh and another thing it's a good idea to do this test twice.Once with your foot squarly on the brake pedal and the second time with your foot on the very edge of the brake pedal to make the rod push more on one side of the master pistons,helps to better find those small internal master leaks with only side load pressure.

Pefect. I'm heading home now and will give it a try.Thanks again.

 

[JeepKj03]

It’s a good idea to bleed the breaks out anyways. I’m sure the fluid in there is black, when it should be clear. That will help you towards a good breaking system.

 

[Ry' N Jen]

When was the last time the braking system was flushed and filled with new brake fluid?
I you have no idea, then it would be a good time to do it!
We have ours done one a year.

 

[Jeepguy43]

It’s a good idea to bleed the breaks out anyways. I’m sure the fluid in there is black, when it should be clear. That will help you towards a good breaking system.

Yes it is black. I do agree, I just meant I'd hate to bleed them all then still have the problem and have to replace the master and re-bleed them all wasting fluid.

When was the last time the braking system was flushed and filled with new brake fluid?
I you have no idea, then it would be a good time to do it!
We have ours done one a year.

No idea, I just bought it a month ago.

I didn't have a chance last night to check it, had both my boys at the house by myself so I wasn't able to run outside to do the test. I will do it later today.

 

[Jeepguy43]

OK so I jumped in it this morning to give it the test. I pumped the brakes until the pedal was hard, started it up and with moderate pressure the pedal dropped but not to the floor. It went to a spot and stayed there.

I'm thinking my next step is just to bleed the lines and put new fluid. I'm also going to check and make sure the vacum lines are cracked or anything leading to the booster.