4x4 steer and brake issues

[blacksheepdiesel]

My '06 3500 dually 4x4 has a bad problem, need help diagnosing. Have searched threads and haven't found my symptoms. Stock truck and stock wheels and tires, 244,xxx miles. Just bought it last winter, no history known.



Suddenly while braking and turning a corner the steering required great effort, the brakes were pulsing, and the power steer pump began to whine. Drove the truck home slowly and it was all I could do to turn the wheel while the truck was moving , no power assist at all. In fact, it was much worse than what manual steering should be.



With the front wheels off of the ground and the engine off the steering feels perfect from lock to lock. Wheels off the ground and engine running the wheels turn but there are two or three areas of slight resistance. Wheels on the ground, absolutely cannot turn the wheels at all and the brake pedal pulses when pushed. If I rev the engine a bit and try to turn the wheels the power steer pump starts whining.



Help?!



Godspeed,

Trent

 

[AEdelheit]

Have you checked the power steering fluid level? The power assist brakes run off the PS pump so if the pump fails or runs out of fluid it can take out both the steering and brakes. Id suspect the pump first, the lining in the hydra boost hoses has been known to fail but that usually causes a hissing noise not failure of the system, might possibly be a steering box issue but unlikely.

 

[blacksheepdiesel]

The power steer pump fluid level is fine as it always has been since I bought the truck. ATF+4 is the fluid used.



Godspeed,

Trent

 

[jelag]

Trent... . your problem sends me to the power steering pump or the drive system... as mentioned above... the pump provides power to both the steering and the power brake unit... in most pumps there is an inlet screen and it might be plugged... you might have a bad tensioner on the drive belt... allowing the belt to slip. . with the engine off and cool... grab either the alternator or power steering hub and see if you can move it... (turn it) by hand... if you can the belt is loose and needs attention...

If the above doesn't seem to be a problem... remove the belt and see of the hub one the power steering turns easily by hand... I assume it will turn hard... either from a bad bearing or internal pump problem... and you'll need to replace the pump... . If you can see fluid moving in the unit... I'd drop the return hose... allow the pump to pump out the fluid and I'd allow the bad pump to pump 3-4 quarts of fluid through the system to flush it out... and than change the pump...

 

[blacksheepdiesel]

Update:

Today I started the truck and tried a couple things. What I noticed was that after starting the engine, revving it to 1500 for a minute or so, then shutting off engine, and pushing on brake pedal there was absolutely no power assist as there should be. I did this twice and got the same result each time. While the engine is running there is power assist although it does "pulse" somewhat. Also checked the power steering fluid in two different places and it appears clean with no discernible material in it.

Godspeed,
Trent