need brake help bad please!

[harleytech]

96 Mazda 4x4 drove up to north Ga now the brakes are soft and pedal will get sorta firm then go all the way to the floor before stopping, great front pads, ok back shoes, just pulled all 4 wheels readjusted rear brakes tightened caliper mounting bracket on front corner, fluid was in the mid range so topped it off, checked for leaks, not using any fluid, rechecked, still not fixed, did the reverse brake adjusting, pedal still goes to the floor, but front brakes will lock up now but with pedal all the way to the floor.

 

[pillen140]

did you bleed them?

 

[bduke23]

Could be your master cylinder is shot, and isn't holding pressure. Try pumping the brakes with the engine off, they should get really stiff and almost impossible to push after a couple quick pumps. It it goes to the floor everytime the master cylinder isn't keeping pressure. I just replaced it on mine, it was so bad that when I took the old one out and tipped it I could hear air bubbles going from one side to the other.

 

[harleytech]

didnt have a reason to bleed them, just drove it from fl to north ga, they worked fine the whole trip until i parked it over night

 

[nitrofan1]

I agree with bd23. I'd pressure check the master cyl. Should have a solid pedal when ignition is off. Another issue may be the booster but check the master first.

 

[harleytech]

gotta master cylinder in route to replace tomm after a mess with the wrong one at the parts store

 

[bigblue88]

If you added fluid when it was really low you probably need to bleed them, air can get in if its below a certain point. I would try that before replacing master cylinder, Just happened to me a couple months ago.

 

[helpme]

Master Cylinder Resevoir

How do you change the master cylinder resevoir to the new one?

 

[multiranger]

How do you change the master cylinder resevoir to the new one?

The resevoir should slip out if you pull up on it hard enough... Autozone has a new master cyl and resevoir combo with the stuff to bench bleed it pretty cheap.. get one of those and a new bottle of brake fluid. Read the instructions on bench bleeding and change it out then bleed all 4 corners... If you need detailed instructions let me know...

 

[bduke23]

Mine was real easy to change. There are two bolts, one on each side of the reservoir attaching it to the booster. Undo those and the brake lines from the side of the master cylinder, and it'll just lift out. You will need to bench bleed the new one first (should be a kit and instructions with it) and then put it in place of the old one. Hook everything back up, and bleed all four corners, and your done.

 

[helpme]

Many thanks!

I didn't see any bolts attaching it to the booster. It mounts only to the master cylinder. I'll get the one at AZ and change it this weekend.

 

[harleytech]

ok so now changed the master cylinder, bench bled etc, brakes still weak and goin all the way to the floor but now getting a whooshing sound from the abs system area, abs has not worked in in over a yr ive owned this truck.

 

[pillen140]

if you got air in the abs unit, it needs to be bled using a special tool. did you bleed the lines at the calipers/cylinders already? also, try bleeding the mc again by cracking the lines going to the mc while someone is pressing the pedal and close it while they are holding it down.

 

[bduke23]

Do the brakes grab eventually, but just not very much? And does it hold pressure now when pumped with the engine off? If both are true, it could also be that the brake booster (that big black cylinder the master cylinder attaches too) is no longer working.

 

[helpme]

Question about wheel cylinder repair.

I found one wheel cylinder leaking. Couldn't get the brake line to unscrew so I rebuilt it in place. But all the time I was working on it it was leaking inside from the connected line. Got it put back together and bled that line. Is this OK or should I have stopped the line from leaking before re-assembling? Thanks.