Originally Posted By: Realtech214
Hey guys. My friends hundai elentra (2004 60k mi) is acting up. The power steering pump is quiet when runing, and when you turn the wheel.....until you get to hard over. Iff you turn the wheel to either side all the way, the pump makes the belt squeak like mad. The pully becomes very hard to turn and belt slips. This only happens when the wheel is turned all the way to either side. New rack. New pump. ??! Thanks.
I worked at the Ford steering manufacturing plant for 16 years, so I can shed a little light on this.
I am going to presume/assume that your system is similar to the bazillions of systems out there already.
First and foremost, NEVER turn all the way to the stops and hold the wheel!
The reason you are hearing that squealing and such is because you are dead-heading the pump! Don't do that! When you do, you are really over-heating the fluid. You are creating a serious hydro-dynamic strain in the fluid circuit and that resistance is so great that it will often cause the belt to slip.
These type systems typically do NOT have a pressure relief valve. They work on a concept of flow balance. The pump is always moving fluid, and it balances between the two turn circuits and the main return circuit. When you "turn" normally you create a differential between the two turn circuits, and it still comes back in the return. But when you turn all the way to the stops, the cylinder piston has no where to go, but the pump is still trying to push it!
The reason there is no relief valve is because you do NOT want pressure relief during an emergency maneuver. If there was a relief in the circuit, and you yanked hard on the wheel to avoid an accident, it would have the effect of relieving at the very most critical time you need it most.
If your pump is nice and quite when driving normally, and the only time it makes a great deal of noise is when you turn all the way to the steering stops, there there is nothing wrong with the pump; the problem is with the driver!
If you need a super-tight turn, then turn all the way to the stop BRIEFLY (less than one second) and then back off the wheel just enough to relieve the pressure dead-head. You should be able to clearly hear the strain drop once you do this.
NEVER turn it to the stops and hold it there; you are cooking the fluid badly.