BDR slave cylinder failure

[William Gooch]

NorCal Cobra,
There is a good discussion of this issue on the Backdraft Boys site. The installation of the slave cylinder on my BDR was not satisfactory and appears common to pull type slave cylinders that are mounted to the frame and transmission, whether BDR or not. Three Cobra owners in our local club have changed out their pull type slave cylinders and replaced with a push type slave cylinder. I completed the change over last weekend also. Whether by design or from the original installation, the pull type slave cylinder action in BDR473 felt soft and the clutch did not release or engage smoothly. When put into reverse, the clutch did not engage completely and I had concerns for the life of the thrown out bearing; some of these effects may have been adjustment related. One of our club members has a lift and has fabricated the past attachment brackets and components. His past mechanical experience made the installation easy and took us about three hours. A number of slave cylinders will work, but we used a Rhino Pac slave cylinder utilized on a 91-95 Mazda Miata and the Salvos Part number was S1080. A new bracket was fabricated from angle iron that attached to the TKO500 transmission utilizing existing bolts. The cylinder rod was fabricated from a bolt. Tension on the slave cylinder was maintained by mounting a spring to work against the piston. I have attached photos in my galley of the original slave cylinder setup and views of the new slave cylinder setup. The Dot 3 fluid was dark, indicating heating of the fluid by the headers. Bleeding the system was not difficult, once you figured out how to get the new fluid into into the clutch reservoir, considering its placement up under the fender. I plan to mount heat shields on further reduce heating of the Dot 3 fluids. The clutch now releases much better with less movement of the clutch pedal and reverse is now smooth. I will see how the modification operates over time. Good luck.