Brake Problems. Please help :O (1 Viewer)

[Ken C]

Hello fellow freaks browsing Mud on the night before July 4th.

I have a bit of a problem.

I replaced my front 2 brake pads. Went on a test drive and noticed that the brakes were super soft. Brakes would only "grip" at the end of travel.

So I pulled over and noticed a giant puddle of brake fluid on my passenger rear, so I removed the caliper and it looked like it exploded. The inner pad was gone and the shims and inner side of rotor were ground into dust inside the piston. So I replaced both rear rotors (oem) and califpers+pads (oem).

Now I have soft brakes that give little bite at start of travel and give in/drop to the floor where the actual "bite" happens.

I can pump the brakes softly while driving and it seems like it is getting more firmer but gives in as you apply more pressure.

Another thing. While bleeding the system using the 2 man method. The brakes stopped building pressure towards the end. They just remain the same firmness. In the beginning of the bleeding process, the brakes went from soft to very firm in about 5-10 pumps, but now the "building" of pressure doesn't happen anymore.

Now the question is,

1) do I have a MC problem? It was replaced about 3 years ago.

2) so I have a booster problem? Hasn't been replaced at least since 150K (when I bought it). Now sits at 225K.

2) do I have to remove the ABS unit? There is no where near by where I can enable it. I have the CDL switch and drove with the ABS off, but there was no difference.

3) I've bled each side. PR, DR, LSPV, PF, DF and there are no bubbles. Do I need to bleed for hours in hopes of getting some air somewhere deep??

Thanks in advance for any input/advice.

#MLCGA

 

[ppc]

Sounds like the seals in the MC failed during the bleeding. When bleeding you don't want to have the seals go past the normal range of movement, like letting the pedal go all the way to the floor. The seals get destroyed by corrosion and allow fluid to pass. If you pump the brakes and get pressure but the pedal slowly sinks to the floor that is what has happened.

 

[cruiserdan]

Agressive pedal over travel can also damage the brake booster. In other words both the cylinder and the booster could be toast.

 

[Ken C]

I just replaced the MC and have the exact same problem. No change.

Is there any other problems that can give me the symptoms?

 

[Dragos80]

I would rebleed the entire system again. Maybe 2-3 times, ABS and LSPV included.

Make sure you cycle the ABS a few times per side.



PS
Crawl under the car while somebody else is pumping the brakes. Check for hose bulges and leaks.

 

[inkpot]

Usually when the booster goes bad it results in a really hard pedal, not soft. My booster died on an extreme down hill section of trail last fall. I finished the trail and drove around town for several days before I replaced the booster. I grew up driving manual brakes, so it was really no big deal.

 

[Ken C]

I would rebleed the entire system again. Maybe 2-3 times, ABS and LSPV included.

Make sure you cycle the ABS a few times per side.



PS
Crawl under the car while somebody else is pumping the brakes. Check for hose bulges and leaks.

I just went ahead and deleted the abs and LSPV.

I am now noticing pulling when braking. To the left, slightly.

Seems a little bit better, just a tiny bit.

Also noticed that when I went to bleed the PR caliper after the delete, i got a lot foam and air. The other sides not at all.

After ABS and LSPV delete, how much air can be trapped in the system if all 4 tires are bleeding smooth fluid with no air?