I replaced the entire braking system (master cylinder, lines, rotors, calipers. everything) on my 1989 Mustang, I had discs in front and drums in the rear, i replaced everything with the brake system from a 1994 Mustang so that I would have 4 wheel disc brakes for better stopping power. Now it stops worse than even, the pedal is very soft and i can‘t even lock up the wheels when I slam on the brakes my hardest. it‘s not leaking anywhere and the master cylinder is maintaining full levels of fluid. the mechanic who did the work said he bled the brakes, what could be the problem??
get an aem one, they have the carb legal sticker so if you get pulled over or you have to smog later on, you don't have to worry. short ram or cai; cai gets cooler air but if your area rains a lot, it's better to get a short ram because of hydrolock.
if u don't know the difference between short ram intake and cold air intake why are u buying an intake?? bottom line go to their website and put in ur vehicle's info and order the part it tells u to ** if u go with cold air intake make sure ur buy blow off valve to keep ur motor from getting destroyed by water.
So the brake pedal is hard with the engine stopped ,proving that the brake system is in perfect working condition .Now put on the foot brake and hold it on ,Now switch on engine and you should feel the servo pull in the brake pedal a bit further,it is supplying a greater pressure so that you do not have to press so hard,that is what a servo does ,so what is it exactly that you consider to be faulty.
Just a thought here .you replaced your 1989 system with a system from a 1994 car .so you're using parts that are not new and are 14 or almost 15 years old. Maybe the master cylinder from that '94 donor car is bad a bum master cylinder can have bad internal seals which will cause a soft pedal and prevent maximum braking. If this were my Mustang I would've spent the bucks on a new master cylinder and, while I'm at it, replace the 14 year old rubber brake lines with new ones. Bleeding the brakes did your mechanic bench bleed the master cylinder before reinstalling it on your car? Air trapped in the MC is tough to remove using the brake system bleeding method. System bleeding means .you start at the farthest point from the MC (the right rear) and bleed that circuit .followed by the left rear, the right front and the left front. Using a pressure bleeder can make this an easy task.
did you change the combination valve to the same one that was in the donor car? You need to make sure that the correct amount of fluid pressure is being diverted to the front and rear cylinders. That being said, there most likely is air in the system still. The mechanic working on the vehicle didn't get all of it out. If you have antilock brakes, there may be air inside the Brake Pressure Modulator Valve.
