New 4-pot brakes: do I need to uprate my servo?

[macmattom]

<font face="Comic Sans MS"><font size="2"><font color="blue">This came as quite a suprise to me, but I have seen threads saying that if you uprate to 4-pot caliper brakes you should uprate the servo.

The title probably says it all - I've uprate my front brakes to 4-pots calipers, bled the system and got really good brake-pedal travel - not too far and very firm, even without the engine running and servo operating, so what will an uprated servo give me?

Do I <b><i>HAVE</i></b> to uprate the servo for the new brakes to work, or is this just desirable?

Thanks,

Mac</font id="blue"></font id="size2"></font id="Comic Sans MS">

The pheonix rises from the ashes - just give it time!




(two and a half years and counting - but who's counting!!)

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[Marko]

consider the brake system as 3 mechanisms of multiplying the force of your leg,

1. you got the lever system of the pedal itself
2. you got the servo that uses the vacuum of the engine to exerted force on the main brake cylinder.
3. you got the hydraulic system of the brakes that does the final increase in force. force on the main brake cylinder* surface of the main brake cylinder = force in the brake caliper* surface of the brake caliper piston.


you increased the surface of the brake caliper piston by installing 4-pot's instead of 2-pot's hence increased the braking force trough all brake pedal travel.

bigger servo gives that "new car" brake feeling, where you can brake very hard with little effort. ever had that experience when you drive a new car that its difficult to accustom yourself to the brake pedal,and you jerk the car whenever you brake because the brakes bite immediately ?

[bmcecosse]

You don't 'have' to - it will be up to you to decide if the pedal forces are too high for your leg with the standard servo!

[Rich in Vancouver]

Find a deserted stretch of road and try a few emergency stops.
If you can lock up the brakes with a reasonable amount of effort you don't need a bigger servo.

1975 TR7 ACL764U

[FI Spyder]

Then there's the other end of the spectrum where in the 70's the slightest touch of the brake pedal on a GM car would lock all four wheels and you could turn the steering wheel from lock to lock standing still with your little finger. My '71 Javelin was better with it's Ford Mustang brakes, while light, you could actually modulate them and the steering had "some" centering feel so you got "some" feedback even on an icey road. Moderm breaks aren't so touchy fortunately. It all depends on what you want.



TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra