feildofpain

ok so i changed out a bad caliper about 4 weeks ago and about a week ago started haveing issues.
if your driving and slowlly press down on the brake it goes about too the floor .if you press down as per normal braking it has presure pumping them consistantlly down every third time it goes to the floor .
ive bleed them and there doesnt seem to be any loss of fluid or apearent leaks?
so i was thinking master brake cylinder ? but if your stopped holding the pedal down (when it has pressure ) it doesnt slowlly sink to the floor .
so do i have some kind of elusive air in the line ? or a going bad master cylinder ? any help would be a good thing lol i kinda tried to search it hear and google ? but id'e like input b4 i throw money down on a new mc ..

cruiser54

Thanks for your post.

We’re here to help, but you must understand that all Jeeps are not the same.
In order for us to give you more accurate advice and help, we must know the following, as applicable, along with detailed information as to the symptoms/problems etc:

Year
Model
Engine
Transmission
Transfer case

caged

when you bled it, was the bleeder above the brake line?

F1Addict

Yep, seems like air in the lines but without knowing the details of your vehicle, it's tough to offer sage advice. A key question is do you have ABS? If so, it's very easy for a transient air pocket to work it's way back into the system. But that's just speculation until you give us more data to work with.

feildofpain

it started the slow sinking yesterday i got a new m.c. today ..
so im guessing i messed up the seals by bleeding when i did the caliper ,used the buddy bleeding system .. thanks for tryin though guys

cruiser54

You didn't mess anything up. It just failed..........

diskman

Over my many years of brake work, I have noticed that replacing one worn out part on a brake system will cause other parts to fail also.

Replacing a wheel cylinder or caliper will cause the master cylinder piston to travel to placed it hasn't visited in YEARS. Usually a ridge in the MC wall and it tears the already fragile cups out when the pedal gets floored the first time.

You could also have a bad master from the store. I changed my '92 to a 2002 Grand Cherokee cylinder and booster, replaced all the brake lines and hardware when I swapped axles last spring. Stops on a dime now.