CK1500 Master Cylinder Upgrade (1.34in Bore) | 1988-2000 Chevy/GMC

Bigger calipers need more fluid, plain and simple. This larger 1.34" bore master cylinder is the fix for the low, soft brake pedal that shows up after installing rear disc conversions or upgraded front calipers on 1988-2000 Chevy/GMC CK1500 trucks (C1500 5-lug and K1500 6-lug).

As you upsize brake piston area with a rear disc conversion or a bigger front caliper, the stock master cylinder simply can't move enough fluid volume to keep pedal travel short and firm. This upgrade solves that at the source rather than making you live with a mushy pedal.

What's Included

• 1.34" bore master cylinder
• Adapter fitting to connect to factory CK-truck hardlines
• Bench bleed kit

Compatibility Notes

Fits vacuum booster setups ONLY — not hydroboost. Stock hardlines will need slight readjustment to align with the new master cylinder ports. The low fluid level sensor is not used on 88-00 OBS trucks.

This is the single most common add-on paired with our disc brake conversion kits and caliper upgrades — if you're stepping up piston size anywhere on the truck, budget for this master cylinder at the same time and save yourself a comeback trip under the dash.