85stang1373

What do i need to do to replace and install a new master cylinder? My brakes are horrible right now. I heard that i needed to "bench bleed" it but ive never heard of that in my life.

any input would be great
thanks

PRO50SC

OK, first of all, how do you know it's the master cylinder that is the problem. Brakes are something very serious and if you have no clue what you are doing maybe you would be better off taking to a shop to be looked at.

What exactly is the problem besides them being "horrible"?

wrenchturner75

just make sure you get a bleeder kit. sometimes they come with the master cylinder some dont. clamp one mounting ear in a vise and screw in the plastic adaptors into the threaded ports on the master cylinder, now put the hoses on each adaptor and stick the other ends in side the master cylinder resivoir. now fill the resivoir with new brake fluid and make sure the hoses stay submerged in brake fluid, now take a phillips screwdriver and slowly push the piston in on the mastercylinder, youll see a lot of bubbles coming out of the hoses then release the plunger. do this until you see no more bubbles then you can install it on the car. i always bleed all 4 brakes out to get any remaining air out and to flush all the old brake fluid out. make sure you start at the r/r then go to the l/r then r/f and l/f.

85stang1373

Well pro, they go to the floor every time i press them. I replaced brakelines, cailipers, (pads, shoes, drum assembly kit, drums,rotors) and bled them like 10 different occasions. I was thinking about jsut taking it to a shop but i thought id come here for advice first. My buddy told me he thought for sure it was the master cylinder. I kinda thought it was the brake booster but i really dont know that much about brakes. What could be the problem?

wrenchturner75

its very possible that fluid is bypassing the seals inside the master cylinder when you push the pedal, also pull the master cylinder forward and check for any brake fluid where the rod goes into the master cylinder, this fluid if leaking can also ruin a booster. and make sure your rear brakes are adjusted properly, should here brakes lightly drag the drum when drums are installed. good luck

85stang1373

When i press the pedal, the brakes go almost 1/8' off the floor and then engage. They have been like this for awhile now and ive been trying all kinds of different things. Now do you think i should replace the brake booster and the master cylinder at the same time and save the hassle for later if its one or the other?

86whitepony

dude it's the booster, mine is doing the same thing, it did the same on my other homies fox. soooooooo we replaced the booster then da dang da dang you got yourself some brakes, and yes you should replace both at the same time. booster and m/c that is. some companies dont warranty the booster unless u replace the m/c

jman511115

Take it to a shop. If you have no clue what you're doing, things can end up very bad.

PRO50SC

OK, just wanted to make sure you weren't randomly throwing a part at it. Sounds like you're on the right track

The booster going bad is NOT going to cause a low pedal, it will cause a hard pedal. It would still have the normal height and NOT sink to the floor.

It's not the booster!!!

JamesIngerman

+1 on the shop if you have no clue what your doing