Power Steering Pump

[MAGNUM SERVICES]

My 96 Sierra 2500 4X4 has a new problem. I replaced the Power Steering Pump (reman) and the Hydro Boost (reman)for the Brakes about 5 years ago but not any hoses or the Steering Box and now I am noticing my Steering get stiff and my Brake Pedal going to the floor, so I thought the Pump was going bad again and replaced it (reman) but my Brake Pedal still goes to the floor and my steering gets stiff but not as often as it did before I replaced the pump. My question is, is there a "check valve" somewhere in the system that could be sticking causing momentary loss of pressure?

 

[WarWagon]

The PS pump is stopping cold due to slipping belt from a bad tensioner, Pulley slipping on PS shaft or the relief valve is sticking open. The relief valve is generally in the PS pump. Also possible the booster or steering box is stopping flow and popping the relief valve. Turn the wheel to a lock and hold it this will show you if the PS pump belt is slipping as it will generate enough pressure to pop the relief valve and you can hear the system strain. You will feel the belt slipping as the wheel pulses or hear it. Floor the brakes for extra strain.

The accumulator provides brake pressure should the engine stall. Likely it works at full lock or with a belt slipping. Test it with the engine off. You should get 2-3 pumps before you get a hard pedal. Booster failure could pop the system relief valve.

I do not know how the ps box could jam and cause high pressure but I suppose it is possible.

Kinked or internally blocked hoses are possible.

 

[MAGNUM SERVICES]

Pulley is tight on Pump, New Belt and Belt Tensioner is about 3 yrs old

 

[WarWagon]

Pulley is tight on Pump, New Belt and Belt Tensioner is about 3 yrs old

It looks like there is something that is blocking flow and popping the relief valve then. Does the pedal go to the floor with the engine off? I suspect the booster may be the issue.

 

[MAGNUM SERVICES]

No Sir, the Pedal feels as it should

 

[WarWagon]

Then the pedal going to the floor randomly would be a booster issue or failing master cylinder allowing the pedal to hit the floor. This may cause the booster to hit an internal stop at full pressure. I am guessing... I can't think of any reason the pedal would hit the floor as the master cylinder has to be bottomed out to let that happen. Possible rear wheel cylinder failure or air in rear lines?

I see you have a 1996 with ABS. Possible the ABS is going off and letting the pedal hit the floor? Again not normal.

 

[btfarm]

Try taking it out on a wet grass field, get going about 25-30 and hit the hooks to cycle the ABS. See if that makes a difference. Have you changed the fluid lately?

 

[MAGNUM SERVICES]

The problem has not surfaced since a day of driving after replacing the pump, Thanks to all who replied