Hydroboost Unit

by Mike Richards

When I bought my í55 bird in early í99 the first thing I did was fit power steering and a power front disc brake conversion from one of the major t-bird suppliers. The power front, manual drum rear never felt very good to me, and despite the addition of a combination valve and adjustable pressure valve for the rear, the system was very sensitive to rear brake adjustment. A couple of months ago, I started working with Paul Clark at Hydratech Braking systems (http://www.hydroboost.com/) to build an adapter for the Ďbird. Part of what drove this was a rear disc conversion I had found for the Dana 44 rear axle.

With the help of a friend, we mocked up the boost unit on sheet metal plates, clocked it to clear the valve covers, mounted the master cylinder on a clocking plate, and sent the whole works back to Paul. A couple weeks later we got the adapters back, recreated in 5/8Ē aluminum, and installed the whole unit.

The unit bolted in with no modification, clears the valve cover, and clears my Redís headers. I had an Optima battery in the car, which I replaced with a slightly smaller Odyssey to get clearance for the hose connections. I think the narrower stock battery would have cleared, but Iím not sure.

Looking a Mummertís headers, I think they would clear, too.

In the midst of this, I bought a polished m/c with a finned top, and discovered the fins were a slightly out of line with the fins on the valve cover. We tapered and shimmed the adaptor slightly at the firewall to clear this, but it wasnít noticeable with a stock m/c and el cheapo chrome cover.

Iím powering the boost unit with a Saginaw pump, as the car is fitted with a Cavalier R&P unit (thanks to this site), but Paul says virtually any pump will produce sufficient pressure. If the Ford pump will run the rack, I tend to believe him.

We had some issues bleeding the rear brakes (more on that when I post that article), but with a 1 1/8Ē disc/disc master cylinder we saw 1100 lbs pressure at the front and rear brakes (proportioning valve set full open) with firm pedal pressure, and 1250 lbs if I jumped on it like a panic stop. At 60 mph, you can start to lock the front brakes, and modulate them back to turning without resorting to pumping.

All in all, Iím very happy, the boost unit brings the brakes in line with the other changes I've made.