BRAKES ISSUE! need help!

[808countryside]

I have a 1985 nissan 720 and i changed my brake pads because it was worn down. Then i bled the front brakes cause that what you normally do ( i think). but now my when i depress my brakes the brake pedals sinks very slowly. so, i bled the back brakes because i figured that there was air in the system. but im still having the same problem. Did anyone encountered this problem or know the fix to this problem? I really need help A.S.A.P.

thanks.

[newnissanfanatic]

Did you actually disconnect the brake line from the piston, if not then you dont need to bleed them. Also, if you bled them to much you might be low on brake fluid now and that could be your problem.

[808countryside]

when i bled the brakes i made sure i had brake fluid. but yes i did disconnect the brake line from the brake caliper because i exchanged it with a new one.

[86 720]

Bleed the entire system. Start from right rear, than left rear, front right and finally front left. Make sure the brake reservior never goes dry or you'll need to start again.

Also make sure you firmly seat the bleeder screws when done.

[sawyer's720]

also on the front calipers you need to compress the piston down or it wont get all the air out of the calipers because of the location of the bleeder screw. i had this problem and it stumped me for weeks and cost me three bottles of brake fluid to figure it out. just an fyi

[newnissanfanatic]

The easiest way to compress the piston without damaging the outer portion is with a C-Clamp. I have done this on other vehicles in the past.

[sawyer's720]

The easiest way to compress the piston without damaging the outer portion is with a C-Clamp. I have done this on other vehicles in the past.

I would also use the old brake pad as a board to put pressure on the piston more evenly. plus you can avoid a slip off or what have you.

[Rev_D21]

Make sure you didn't miss bleeding the prop valve under the bed. Did the system go dry recently? Is a caliper hung up?

[808countryside]

yes, i made sure i bled the valve under the bed. but, today i bled all 4 brake lines in the correct order (rear right, left rear, front left and last front right). so well see if that fixed the problem. if that fails, do you think the brake master cylinder is bad? is it hard to change?

thanks to everyone for your advice

[sawyer's720]

in most cases you can tell if the master cylinder is bad based upon visible leakage. when i changed mine there was a leak between it and the brake booster. the cool thing is that changing the master cylinder is only a five to ten minute job. but after swapping it is necessary to rebleed the whole system. the only other problems i could think of would be a leaky brake hose, a bad booster or not compressing the piston in the caliper while bleeding. which was my problem.

[captainzeros]

Actually, there are just as many or more seals inside of the master cylinder that can leak from inside the MC to the other bits inside the MC and be totally invisible. Master cylinder leaks can be totally invisible from the outside.

[808countryside]

my brakes are doing pretty good so far. but i had one more concern, is it normal for the brake pedal to sink a little or at most halfway. the pedal never did sink to the floor though. i also didn't see any brake fluid leakage near the hoses or by the master cylinder or the brake caliper.

[94fordman]

how would u compress the piston on the caliper while bleeding the system put c clip around caliper with brakepad and push brake peddle or just crack bleeder a little and compress

[86 720]

how would u compress the piston on the caliper while bleeding the system put c clip around caliper with brakepad and push brake peddle or just crack bleeder a little and compress

You wouldn't You bleed the system AFTER the pads have been replaced and the caliper is mounted back on to the rotor.