The Hydroboost hydraulic brake booster is a popular upgrade for many classic cars and street machines.  These boosters are commonly found in vehicles with turbo diesels or other supercharged engines, such as Chevy Silverados, Mustangs, and even Chevy Astro vans.   The Hydroboost is smaller than a vacuum booster, and provides great power brakes for normally aspirated engine cars as well as those with supercharged engines, where vacuum boosters don't work.  Used or rebuilt boosters provide a low-cost solution to your brake booster problems.  You must have a power steering pump for the Hydroboost to work.

One of the critical pieces you need to install a Hydroboost brake booster on your car is the mounting adapter.  This is the part that allows you to bolt the unit to your firewall.  Along with that you need to supply the master cylinder and power steering lines, which we do not provide.

The adapters are designed to mount the booster so the accumulator is opposite the engine for good clearance.  They are CNC laser cut from .250" steel. The first is the economy model that is attached to your hydroboost unit using the large nut on back, then the assembly is slipped over the four original master cylinder mounting studs.  Nuts are not included.

The upgraded "smooth" model is designed to eliminate the nuts on the firewall side, and provides a smooth, custom appearance to the installation.  The studs in the original brake pedal brace must be removed, and the new nuts are installed from the inside.  Nuts are not included.

Both of these Tri5 adapters will work on 55-57 Chevys of all models, 58-64 Impalas, 55-57 Pontiacs, 55-57 Oldsmobiles, and many other cars that have a 1.7" x 3.4" bolt pattern. Some slight clearancing of the large opening in the firewall may be required to clear the large nut on the Hydroboost unit.

The "Universal" hydroboost adapter will fit any car or truck with two 3/8" bolts on a 3.2" to 3.4" spacing with a flat area around the booster opening.  This includes many Chevys, Fords, and Mopars.

This kit allows you to bolt 1992-2002 Cadillac Eldorado or DeVille power bucket seats into your 55-57 Chevy.  The Eldorado seats are recommended for 2-door cars while the DeVille seats work in 4-door cars best because they do not fold forward for rear seat entry.  These seats are a good fit into the Tri5 Chevys and provide 12-way power and even heat on some model years.  Some minor modification of the aluminum tracks is required and some custom fitting of the inboard seat mount is necessary to fit your car perfectly.  Kit comes with full installation instructions. $21.90 flat rate USPS shipping in the continental US (lower 48 states).

Tri-5 Cadillac Eldorado seat mount Kit  $300

55-57 Chevy, Olds, Pontiac and 58-64 Impala - Smooth mount model


$80.00  shipped in Continental US

55-57 Chevy, Olds, Pontiac and 58-64 Impala - Economy model


$45.00 shipped IN COntinental US

Hydroboost Mounting adapters


FOrt Collins, Colorado

"Universal" model   $45.00  shipped in Continental Us

Will fit any car or truck with 3.2" to 3.4" bolt spacing and pushrod opening centered between bolts.