My brakes on my 95 magnum are not working. I have gone thru the completely. plenty of fluid calipers are working and replaced the master cylinder and bleed them. But it seems like the are not building pressure to operate the brakes. What to do now?

 

My experience with this problem has been that you have air trapped between the cup seals inside the master cylinder. This has frustrated me whenever I rebuilt or replaced a MC of such a small size.

I find it better to remove the master cylinder and place it in a vice. The below procedure is messy and if you get brake fluid on something it will most likely remove the paint.

You should wear eye protection!!!

1. Remove the brake line from the MC.
2. Make sure the reservoir is full.
3. Place your finger (or thumb) over the brake line hole.
4. Squeeze the lever slowly while keeping finger pressure on the brake line hole.
. a. You should see very tiny air bubbles coming up through the fluid in the reservoir from one of the holes in the reservoir.
. b. You only need partial strokes.
5. Repeat this many times until you see the air bubbles cease. (It will take a lot.)
6. The MC should now be "primed" so try to get the brake line back on the MC as quickly as possible.
7. Continue with the bleeding of all the rest of your calipers.

 

Good instructions from Diverod on priming the master cylinder. Another way on these old rubber type brake lines is to clamp off the brake line close to the master cylinder and build up pressure on the master cylinder.Once that's done a mityvac can speed up bleeding the air from the lines while you keep the master cylinder full of fluid.On the mechanical portion of the rear brake loosen the 7/16" lock nut and turn the adjuster bolt in and watch the foot brake rise. Stop when the bottom of the pedal is a 1/2" from the floor board and tighten the lock nut. When these old mechanical brake models are working good they can lock up the rear wheels.