Power Steering & Brakes gone!!

[777stickman]

'98 K2500 7.4 Sub. Yesterday morning startup found me with no power steering or brakes (hydro boost). Belt was on and the power steering pump was running and full of fluid. Got a pump on order, as I've heard the shafts are prone to internal failure. Around noon I started it up to move it up to the shop and it was ok, both steering and brakes were back??? Drove it last night and the brake pedal felt a little different. Looking at the hose routing it appears the pressure comes out of the pump to the hydro boost and then to the steering box and return to the pump. Could the hydro boost be bad or a combination of it and/or the pump??

[jrl_1644]

Originally Posted by 777stickman

'98 K2500 7.4 Sub. Yesterday morning startup found me with no power steering or brakes (hydro boost)...

Did you ever find the cause of the above stated problem? My Brothers '99 Suburban has done the same exact thing but his still wont work. Any help would be appreciated. [email protected]

[poconoracing]

Originally Posted by 777stickman

'98 K2500 7.4 Sub. Yesterday morning startup found me with no power steering or brakes (hydro boost). Belt was on and the power steering pump was running and full of fluid. Got a pump on order, as I've heard the shafts are prone to internal failure. Around noon I started it up to move it up to the shop and it was ok, both steering and brakes were back??? Drove it last night and the brake pedal felt a little different. Looking at the hose routing it appears the pressure comes out of the pump to the hydro boost and then to the steering box and return to the pump. Could the hydro boost be bad or a combination of it and/or the pump??

This is from the 1998 Chevy Sub Service info:

Hydraulic Booster Functional Test
System Tests

The hydraulic booster uses fluid pressure from the power steering system. A malfunctioning power steering system can affect the hydraulic booster. A malfunctioning booster can affect the steering system. Before beginning extensive testing, perform the following procedure.

1. Check all power steering and brake pipe connections for leaks and restrictions.

Notice

Power steering fluid and brake fluid cannot be mixed. If brake seals contact power steering fluid or steering seals contact brake fluid, seal damage will result.
2. Ensure that the master cylinder is properly filled.

Notice

Power steering fluid and brake fluid cannot be mixed. If brake seals contact power steering fluid or steering seals contact brake fluid, seal damage will result.
3. Ensure that the power steering pump reservoir is properly filled.
4. If the power steering fluid contains air, refer to Diagnosis of the Power Steering System in Power Steering System. Check the power steering pump belt for wear and improper tension. Refer to Diagnosis of the Drive Belt System in Engine Cooling.
5. Check the power steering pump pressure. Refer to Power Steering System Test in Power Steering System.

Functional Test

1. With the ignition OFF, apply and release the brake pedal several times. This will empty the accumulator.
2. Apply and hold the brake pedal with 180 N (40 lb) of force.
3. Start the engine.

The pedal should fall away, and then push back against your foot.


Apparently the Power brakes use fluid pressure from the PS Pump.

[jrl_1644]

My brother told me that it happened when he was driving off-road. He said his front tire hit a big bump while he was turning and braking. He said it felt like the ABS came on then both the power steering and the brakes went out.
I will try the above test procedure when i get home thanks for the reply.

[777stickman]

Originally Posted by jrl_1644

Did you ever find the cause of the above stated problem? My Brothers '99 Suburban has done the same exact thing but his still wont work. Any help would be appreciated. [email protected]

Turns out that my power steering pump was going bad. Replaced it and all is back to normal now.

[jrl_1644]

Originally Posted by 777stickman

Turns out that my power steering pump was going bad. Replaced it and all is back to normal now.

Thank you.