Pads good, fluid good, still brake fade

[PsyRN]

My brakes have been getting soft lately, and sometimes I can even push the pedal pretty far down while still sitting in the driveway. I thought maybe my pads were worn, so I pulled off the first set in front and they are just fine. The fluid is near the max line too. Maybe 5mm low.

I have 34,000 miles, although I just put a 300lb camper on back about 4000 miles ago.

What's going on? do I need to pump the brakes with the fluid reservoir off? not sure what to do. should I replace the pads even though they aren't worn? I compared them to a new set and they have lots of pad left.

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[bd100]

Flush the lines, and/or look for bulging soft lines at the corners?

 

[Richgoat]

Probably your brake booster. I had the same issues on our Pacifica, now there's a recall out for it on the Pacifica. They probably share the same part # but if they're fading and pedal going to floor there's a good chance it's that.

Did you notice the brake hissing louder when you press the pedal down?

 

[ShadowsPapa]

Probably your brake booster. I had the same issues on our Pacifica, now there's a recall out for it on the Pacifica. They probably share the same part # but if they're fading and pedal going to floor there's a good chance it's that.

Did you notice the brake hissing louder when you press the pedal down?

Brake booster is about boosting. If a booster fails, it will have a hard pedal when it's down farther than normal.
Would be interesting to see the difference between brakes when the engine is off, button is off, and the brake vacuum is depleted by pumping the pedal a couple of times or so to "use up the vacuum" in the booster.

Someone else had an issue and found the brake cylinder wasn't secured to the booster - they'd had a nut off or something, anyway, check how the booster is mounted to the truck and how the master cylinder is mounted to the booster. Things flex with that much force if not tightly secured. Any loose bolts or nuts need to be dealt with.

If it was an old vehicle, I might think brake hoses - but geesh, there's 40 year old brake hoses out there still not giving a lick of trouble so it's tough to imagine a <3 year old brake hose bulging so much it caused a soft pedal. But maybe one was stretched beyond normal limits at some point, damaging the cords that bind it from bulging.

 

[Richgoat]

I had the same symptoms as the OP. If you held the pedal long enough it would go down to the floor eventually and the vehicle would start moving. During driving it would seem ok until it wasn't. It was the booster. No hard pedal feel, if anything it was the opposite.

I strongly suggest you look up the part # to see if it matches the Pacifica booster (same engine in jeep and Chrysler, 3.6). If it's the same I'd urge you to have dealer check and replace the booster before something awful happens. My dealer was clueless and finally replaced it with guidance from Chrysler cares. Two months later they recalled it.

 

[PsyRN]

I had the same symptoms as the OP. If you held the pedal long enough it would go down to the floor eventually and the vehicle would start moving. During driving it would seem ok until it wasn't. It was the booster. No hard pedal feel, if anything it was the opposite.

I strongly suggest you look up the part # to see if it matches the Pacifica booster (same engine in jeep and Chrysler, 3.6). If it's the same I'd urge you to have dealer check and replace the booster before something awful happens. My dealer was clueless and finally replaced it with guidance from Chrysler cares. Two months later they recalled it.

it's not the same part numbers. Gladiator: 68465215AA, Pacifica: 68349447AA

I'm going to try and flush the brake lines. Maybe I have air or something in them.

 

[ShadowsPapa]

These have to be totally different animals than other vacuum boosters, then, because normally, the rod going from the pedal to the master cylinder itself is non-collapsing, and the vacuum diaphragm does the work. If it fails or there's no vacuum, then you are pushing directly onto the master cylinder piston without aid.

Other than digging through my books, this is the best I could find, and it shows how the rod goes clear through, basically to the master cylinder. There's adjustment on the master cylinder end of the booster rod to allow for some clearance to ensure the master cylinder piston can move all the way back.

 

[PsyRN]

I ended up flushing the lines. Seems to have worked.

 

[willys 41]

I had the same problem and this is what I found out
https://www.jlwranglerforums.com/forum/threads/the-wrangler-mushy-brake-syndrome-finley-fixed.82912/

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