Brake servo conversion

[Mike Robo]

I know this subject has been pretty much flogged to death, but I'm hoping somebody can explain a couple of things. With the change from the Saab servo to a Ford Fiesta servo, http://www.pistonheads.com/gassing/topic.asp?h=0&a... I have found that the new Ford servo can be mounted to the original holes, but the piston is approx 3mm of centre with the pedal. The piston has enough play to move in the vertical plain to allow for nonlinear movement created by the pedal hinge. The piston also has enough horizontal movement to reach the brake pedal without the new holes drilled in the bulkhead. What would be the implications/problems if I just left it? All I can think of is increased wear.

Second one is, there are apparently 6 kinds of master cylinders. I've got the master cylinder with the servo from a breakers and have no idea which one it is. What would happen if I had the wrong one but fitted it anyway?

I'm looking to make my life easier but if there is valid reason I should'nt be lazy, I would much appreciate hearing it!

[mep12345]

Mike Robo said:

Second one is, there are apparently 6 kinds of master cylinders. I've got the master cylinder with the servo from a breakers and have no idea which one it is. What would happen if I had the wrong one but fitted it anyway?

I understand the differnt types have the following changes:

2 differnt bores 20.6mm and 22.2 mm - the S needs the larger, if you use the smaller you will have more pedal movement for the same amount of braking power as you displace less fluid.

Different pipe connections - IIRC 10mm and 12mm seem to be the options this will only mean you may need to change the pipe union on some of the brake pipes.

There may be other differences, but not that I'm aware of.

HTH

Mark