Engine/Transmission (1998.5 - 2002) Troubleshooting soft brakes

[Sregorb]

Alright, I'm turning to the experts:

Symptoms are engine off depress brake pedal and tightens brakes (does stop truck). Slooowly continues depressing (with same amount of force) until hits floor (~5 sec).

About 48k miles, brake fluid resv full-tan color, no brake or tire service done in last 3k, started last week suddenly. No leakage showing on garage floor.



Air/water in the lines... somehow?



Brian

 

[R-N-R]

I just happened to read a bunch of threads tonight that described your symptoms and attributed them to Master Cylinder internal leakage.

 

[Sregorb]

Interesting. Does that imply a warranteed item if it is the master cylinder?

 

[R-N-R]

Not positive, but my first thought is that would be covered under the 36k not the 100k warrenty.

 

[HOSSBOBCAT]

soft pedal

I had the same problem with my 99 replaced the master cylider no help. replaced rear wheel cyliders $26 adjusted rear drums works great.

 

[Cummins360]

Yea that deff sounds like master cylinder internal leakage or else wheel cylinders, but unless it's leaking brake fluid I would guess that its the master cylinder.

 

[DieselTweaker]

Could be your brake hose's, or master cyl.

 

[Nate]

Sounds like the same problem I have with my truck.

 

[Sregorb]

I was thinking air in the line(s) and was planning on bleeding the whole system with a fluid swap. I hopped in and pumped the brakes a bunch with no hint of a leak showing anywhere so I'm not sure how/where the problem is. If the engine is off does that isolate the master cylinder as the cause or is it just that "somewhere" in the fluid path there is a compressable area?



oh, and I checked, it's disk front and back if that makes a diff...



Brian

 

[Cummins360]

That usually is pointing to the master cylinder internal leakage, it is probably fluid leaking past the seals internally. There shouldnt usually be any compressable areas in the brake lines, and if it was air it would be spongy all the time.

 

[Sregorb]

Ok, slight confusion. It is spongy all the time... even when the motor is off.