2000 K3500 hydroboost brake issue

[Tom P]

So I've had my truck for a while now, not quite a year. Had a shop do an alignment, rotor turn and brake fluid flush back before summer. Everything was inspected and they even turned down the chance to replace calipers and pads too. Claiming it wasn't necessary. Have had no issues with them until this past week. On occasion and usually at low speeds (i.e. Parking lots and driveways etc) I'll go to apply the brakes and once I get just enough pressure to completely stop the truck, the pedal softens and I lose some of my braking. Usually by pushing harder I can then get the truck stopped. I have not yet had to pump the brakes to stop. From what I've read this sounds like a master cylinder problem. I have not detected any brake fluid leaks. Does anyone have any info to confirm or negate this diagnosis?

 

[rojas84]

I'd look at the master cylinder, also how is your steering any issues could be power steering pump since it's ties I. To the hb system

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[Tom P]

Steering is fine. My power steering pump is a little noisy but other than that everything else seems to work normally. After the issue started I checked to make sure the fluid levels were still good. Power steering pump was a little low on fluid so I topped it off, and the brake reservoir was level full.

 

[deejaaa]

do you have any fluid around the hb area? that would be ps fluid. if you do then the o-ring is giving up the ghost.

 

[Tom P]

I haven't specifically scoured that area yet. I will after work and report.

 

[Tom P]

No apparent brake fluid leaks or PS fluid leaks that I can see...