Power Clutch - Geo Metro Brake Booster - Write up 3/22/04
Back in Week 33 ( a couple of years ago) I talked about having to change the clutch hydraulics to support the new Howe throw out bearing. What I ended up with was a Tilton 1" Master cylinder bolted to the firewall which directly operated the slave cylinder. Although this worked, clutch pedal effort was extremely hard and I noticed that the bulkhead was actually flexing as I was operating the clutch. Because the firewall is just sheet steel, I knew it wouldn't be long before I started to get metal fatigue and serious problems would then start happening. I started to think of ways to decrease the pedal effort but keep the hydraulic arrangement that I currently had. I decided to try a remote pedal arrangement. I had the 3/4" Tilton master cylinder left over from tinkering with the Howe bearing. I figured I could use this cylinder on the bulkhead. If I got a 3/4" slave cylinder, I have the beginnings of a remote pedal. The easiest way I thought of to decrease pedal effort was to use some form of power brake booster. I needed something small that I could fit on the battery tray. I looked around and noticed that the Geo Metro brake booster would probably work. I had machined two aluminum plates - one plate to bolt at the back of the booster to hold the 3/4 slave cylinder. The front plate would adapt the bolt pattern of the geo booster to the Tilton 1" master cylinder. The way the system works now is that the 3/4" Master and Slave cylinders give me a remote pedal mount. The slave cylinder directly operates the 1" master cylinder through the brake booster which gives me the assistance I need (and greatly reduced pedal effort). There are two separate hydraulic systems for the clutch now but operating the clutch when the engine is running is now nice and light with no bulkhead flex.
Pictures of the booster and brackets: