Suspension, Brakes and Tires Discussion, 76 mushy brakes, help? in Item Specific Cadillac Discussion; once long ago, i pulled drums off another car, i'm sure i'll get the brake drum off next time i ...
once long ago, i pulled drums off another car, i'm sure i'll get the brake drum off next time i try.
Also, i was told that theres a valve in the braking system that can "switch off" the hydrolic system going to the back brakes if it sences a loss of pressure back there as a saftey device in case you blow out a line or some thing. so that you will still have front braking (works vice versa too). any thoughts about this dohickie?
So i replaced one of my brake cylinders in the back, the dam auto parts store sold me the second one with a torn boot right out of the package so i'll have to wait to get the other side. the cylinder i took out looked like crap. i pushed on the rubber boot of the old one and it ripped right away. there ws no fluid behind the boot so i figure it was clogged.
I tried to bleed out the breaks to see what i'd get, still nothing coming out of the rear, then i blead the front i got a squirt then just a little dripp dripp. i was bleading with the car running and some one stepping up and down on the peddle so i'd have lots of pressure. It seemed like i had very little pressure all the way around. Once i replace the other rear cylinder, i'm going to try again. i think its starting to look like the master cylinder....
All four aren't getting pressure? Well... The master cylender runs into the metering valve which then splits off in all four directions. The metering valves purpose is to cut off pressure from the front brakes until the rear shoes contact the drums. The system needs it to do this because the front pads are normally very close to the rotor while not engaged compared to the shoes that are miles away from engagment when not being used. What makes me hesitant on saying that it's bad is that normally when a metering valve goes bad, it only cuts off pressure to the front. So the only thing left that is connected to all four brakes would be the master cylender, and that can produce the exact syptoms you describe when it goes bad. Still, there are tests you should do just to make sure that it's bad in the first place. Disconnect the lines from the master cylender side of the metering valve and see if there's pressure there, if not you know it's the master cylender. To find the metering valve, simply follow the lines from the matser cylender to the first item that they run into.
Since the cylenders in the drums are fairly cheap (I think), you're doing the right thing by replacing them too.
yea the cylinders are like 10 bucks each... the master cylinder is only like $35. after replaceing the other brake cylinder i'll test and see where i have (or haven't) pressure. thanks for all of your help!
so after changing the master cylinder and beeding the breaks out, i'm all good!
your going to laugh at me but i'll tell you anyway. I replaced a line for my hydroassist a little while back. when i did i topped off the master cylinder with steering/transmission fluid because i thought the brakes and steering shared the same fluid, no they just share power! So with a little petrolium product in the breaks it made my master cyl gaskets swell and freeze, the one for the back just happend to go first!
live and learn i guess! but now i can move on to other thngs and we can kill this thread! thanks for all of your help!