Back in the fiero world 😁 (Page 1/1) pontiacfierokid1985 JUN 30, 02:47 PM Hello everyone im back picked up another gt 86 fastback gt early 86 4 speed muncie 2.8. My question im looking to ask is about the grand am brake up grade. Im not doing it on all four wheels just in the front now i got the hubs cut off the rotor and turned to fit the grand am rotor. New hummer h3 studs pressed in and also grinder down the fiero bracket so the rotor dont rub. Im using the s10 master cylinder will this be a problem with the rears locking up? Is there a upgrade for the rears where i can use the fiero e brake and cables since i need them to pass inspection here in massachusetts. pontiacfierokid1985 JUL 07, 02:07 AM 45 views and no one knows what master cylinder from a s10 will work? also will it cause the rear brakes to lock up? fieroguru JUL 07, 10:33 AM Google is your friend... http://fierozone.tripod.com/realbrakes/index.html FWIW... switching to a larger brake master reduces line pressure and caliper clamp pressure. So no, installing it will not make your rear brakes lock up sooner, it will make them significantly less effective, which is normally a bad idea. If you are going to go down the route with using calipers with significantly larger piston areas, you need to do the same front/rear and then use the larger brake master for the needed fluid flow. Doing only one end of the car will greatly shift the brake bias to that end and result in an overall less effective brake system. pontiacfierokid1985 JUL 07, 07:26 PM So with this should i do the s10 booster or no im going to be doing the brake conversion tuesday once the hubs are picked up from the machine shop