Does anyone have some input on what effects I may cross by putting an oversized power steering pulley on my pump? I stuff the last one which was 100 mm diameter, I've been offered a replacement that is 120 mm. I'm thinking it may cause excessive pressure in the system, or will spin the pump too fast which I'm afraid may stress the pump too much. Can I offset any pressure by reducing the viscosity of the pump fluid? Not sure what other problems could be involved.

The unit is going on a 2.8 in a 99, still has the factory steering box, and the patrol is lifted 2" and sitting on 33's. I'm open to having the steering box rebuilt to accommodate the needs of the pump with the bigger pulley. If anyone has the same pulley for sale then I am interested.

Thanks