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Discussion Starter · #1 ·
Has anyone who has done this upgrade swapped the Master cylinder as well?

Completed my swap this past weekend and everything went smoothly, and the car's driving/braking great. There is just the ever-so-slight pulsating under very hard braking. And I mean ever-so-slight.. Most people may not notice or care, or even feel it if they weren't driving and braking very hard.

But since I do feel it, I'm curious if the stock R/T master cylinder and Scat Pack/SRT master cylinder are different and, if so, it the SRT master cylinder can be swapped in place of the R/Ts?

Worth noting - the pulsating was pretty bad during the first few drives at even mild braking, but it went away (or devolved into what it is now) within the first day.
 

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The below applies to performance or spirited braking. Any less than said for the average driver it may not apply.

You should check or have your rotors checked for run-out with a dial indicator. They should be less than 0.002". Mine are either 0.00 or 0.001.

What you feel is what some think is warping but its most likely uneven material transfer. If you have too much run-out the high sides pass across the pads harder than other parts of the rotor and you get uneven heat, material transfers and you get hot spots.
Causes of run-out other than low quality or defective rotors or pads can be anything from dirty rotor to hub mating surfaces, bad wheel bearings, or uneven or over torquing the lug nuts. Or even not bedding them in properly, or any combination of said here.

If we are going to be performance braking (making lots or heat) we need to make sure we have minimal rotor run-out.

Clean you mating surfaces.
Make sure your wheel hub bearings are ok.
Use conical washers to bolt your rotor onto the hub for taking measurements for run-out.
Always use a torque wrench, never an impact wrench. I know Discount tire will oblige you if you take them in for a rotation. That's a great service.

checking_4_runout.jpg


conical_washer.jpg
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hot_spots.jpg
 
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The R/T and SRT master cylinders are different, however swapping master cylinder isn't a requirement. Mine worked just fine, I was only planning on putting in the SRT if mine failed.
 

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Discussion Starter · #4 ·
The R/T and SRT master cylinders are different, however swapping master cylinder isn't a requirement. Mine worked just fine, I was only planning on putting in the SRT if mine failed.
Thank you, that's helpful. Thinking I just need proper bedding or to refinish the rotors. Very minor vibration, just want them perfect
 
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