GAP 100% Bolt-on Complete Hydroboost Conversion Kit for 1999-2007c GM Truck
Introducing our new 100% Bolt-On solution for converting your 1999-2007 (classic) Silverado or Sierra to Hydroboost Brakes. Available for both 2WD/rack and pinion steering applications as well as 4WD/gearbox steering applications.
Note: select 2WD models that used torsion bar front suspension will have gearbox style steering like 4x4/awd trucks. 2WD models with coil spring front suspension will use rack and pinion style steering. Please ensure you select the correct steering type from the drop down menu.
Kit Includes:
- NEW Aftermarket Hydroboost Power Brake Booster (Like GM Part #15854059)
- GAP Bolt-on Firewall Adapter Plate w/ Hardware (Pre-installed on brake booster)
- Power Steering Pressure Line - Pump to Booster
- Power Steering Pressure Line - Booster to Gearbox (or Rack)
- Power Steering Return Line - Hydroboost to Pump
- Power Steering Return Line Tee & Clamps (if kit is optioned without power steering pump)
- OPTIONAL: NEW Hydroboost Power Steering Pump w/ Reservoir (Like GM Part #84996211)
- OPTIONAL: NEW Brake Master Cylinder Like GM Part #18040236
NOTE: Rack & Pinion Applications will include a pre-assembled (hydraulically crimped) 6AN power steering pressure line and 6AN conversion fittings for the steering rack inlet and hydroboost outlet to allow for bolt-on installation without the need for sourcing conversion parts or building hose assemblies.
The firewall adapter plate in this kit allows you to bolt the hydroboost power brake booster directly to your existing vacuum booster firewall bolt pattern WITHOUT the need to cut, notch or drill (MADE IN THE USA with 6061 Billet Aluminum). It is 100% bolt-on and utilizes the existing vacuum brake booster mounting holes. The adapter is designed to replace the OEM firewall plate on the GM Hydroboost unit entirely, allowing for bolt-on installation of the booster without modifications to the vehicle's firewall. The adapter positions the hydroboost pushrod inline with the OEM vacuum booster positioning.
99-07 GM Trucks (GMT800) will be a direct-swap without pedal modifications required. There will be a slight decrease in pedal ratio as the hydroboost pushrod pickup point will be slightly lower on the pedal arm compared to the OEM hydroboost geometry. However, most will consider this an improvement in pedal feel as it will result in a slightly firmer pedal which provides more predictable modulation and engagement. The OEM hydroboost system on the GMT800 trucks can be a bit sensitive, so this resulting change in pedal ratio will improve that feel.
Converting to hydroboost brakes generally offers improved braking performance, better/more consistent pedal feel, and improved clearances in the engine compartment. Forced induction or large cam engine combinations can benefit significantly in braking performance/predictability as both of those factors can negatively impact vacuum brake performance due to reduced vacuum output under certain conditions.
