Thread: Dual 7" Servo
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Old 8th August 2017, 23:53
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Grey V8 Pete Grey V8 Pete is offline
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Having enjoyed the benefits of the dual servo for some time I have found when bleeding the front brakes that a lot of black bits have come out in the collection jar. As that usually means wear in the master cylinder (at 40k miles) I have been looking for either a repair kit or preferably a replacement m/cyl unit. Mine is a Bendix m/cyl with three pipe connections (one rear and two front) and has a 23 on the raised boss but I can't find anyone who stocks one with a 23mm bore. Does anyone know which model Ford that would have originally been fitted to?

In the above dual servo posts there is talk of 22mm being the normal Sierra size. How does that perform as it is about 9% difference in surface area? I have 10" (Sapphire?) vented discs at the front and 10" solid discs (XR4i?) at the rear. Pedal travel with the 23mm m/cyl is fine so I don't want to increase that if possible.

I do have a s/hand 22mm sierra m/cyl, condition unknown, which may respond to a repair kit but would prefer to stick to the proven 23mm and a new unit if possible.

Feedback appreciated. Peter.
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