When using the 1979-1993 Mustang Rack and Pinion unit with a GM power steering pump the pressure must be reduced to prevent “over-assist”.
Borgeson’s GM P/S Pump Pressure Reducing Shim Kit allows you to fine-tune the bypass pressure on all GM self-contained and Type II power steering pumps. The kit includes a clamping tool, six shims, and detailed installation instructions, making it easy to adjust your pump’s pressure settings for optimal performance. Whether you’re looking to reduce steering effort for a more comfortable drive or tailor your steering system for specific driving conditions, this shim kit provides a straightforward solution to customize your power steering pump’s.
The Following Chart is for reference only, different pumps may vary pressures. Mustang Rack and Pinions generally require Approx 1000 PSI.
No Shims = 1350PSI
1 Shim = 1200PSI
2 Shims = 1100PSI
3 Shims = 1000PSI
4 Shims = 850PSI
5 Shims = 700PSI

