2nd Gen Non-Engine/Transmission brakes locking up and won't release, hydroboost.

[WaltHess]

OK, so here are the deets. 2001 , 3500, stick, hydroboost brakes, 4x4, 327,000 miles, original/stock under the hood. The power steering system has been leaking for quite awhile now, and I am in the process of getting the parts to change it all out IE; gearbox, pump, hoses. Haven't had any problems other than having to add steering fluid all the time. I jump in the truck Sunday ,after moving it around my property earlier without incident, to run a motorcycle over to my friend. I top off the steering fluid and back down the driveway. I turn towards the street, and it won't move forward. Check the transfer case, not jammed in 4 wheel drive. Pop the hood, and everything appears fine, but I hear a popping / creaking sound from the brakes. Shut the engine off, and it sounds like pressure being relieved, then a pop like a check valve releasing. Get in, start it up, truck moves OK, then I apply the brakes. The brakes lock up, and won't release until the engine is off, and the pressure lowers. The (feed ?) line from the pump is very hot. Air in the system, something jamming a valve, new booster needed? This is my first hydroboost braking system, so I am not sure what all is going on here.

Tried the search, but didn't find this problem.

Thanks in advance.

 

[fest3er]

Check rotors and calipers. It's more likely a caliper is seizing. And possible that the rotors are a bit thin (or their cooling fins have rotted out).

 

[WaltHess]

Brand new brakes and rotors recently installed, calipers looked great.

 

[tripl-e]

Brand new brakes and rotors recently installed, calipers looked great.

Master cylinder piston must fully return to 'rest' position to uncover return port for hydraulic (brake) fluid so calipers/drums can relax. If your hydroboost is dirty or corrupted by repeated low/no hydraulic oil in ps system it may not be completely free moving and be preventing complete return of master cylinder piston. Not sure about details of how hydroboost assists brake master cylinder but I'd be looking there first. A work-around could be as simple as lifting the brake pedal with your foot to get the master cylinder piston to return fully.

 

[Missouri Mule]

The rubber brake hoses mite be colasping do to age.

 

[Bob4x4]

Master cylinder piston must fully return to 'rest' position to uncover return port for hydraulic (brake) fluid so calipers/drums can relax. If your hydroboost is dirty or corrupted by repeated low/no hydraulic oil in ps system it may not be completely free moving and be preventing complete return of master cylinder piston. Not sure about details of how hydroboost assists brake master cylinder but I'd be looking there first. A work-around could be as simple as lifting the brake pedal with your foot to get the master cylinder piston to return fully.

Lifting the brake pedal will damage the stop light switch

 

[spacecadet]

Walt,

I had this problem back in 2009. Took the dealer a long time to sort it out, and what they found may not be related to your problem as I was not having to add ps fluid before it happened. https://www.turbodieselregister.com/threads/210432-Overheated-front-brakes-after-servicing