Based on our shop experience specializing in heavy-duty brakes since 1985:

• Diesel Assist Check: On these 1988-1993 models, a hard pedal usually points to a failing accumulator or an internal spool valve blockage. Since these engines lack vacuum, the hydroboost is your primary safety system.
• Hydraulic Hygiene: Always perform a full power steering system flush. Contaminated fluid from a worn pump will quickly damage the new 100% O.E. quality seals in your booster.
• Output Rod Precision: Our master cylinder output rods are pre-adjusted to significantly reduce shop labor time and ensure correct pedal travel from the first stop.