87 nissan pickup,I put a new master cylinder and flushed all the fluid. The wheel cylinders don't leak and the front brakes work perfect. Any suggestions? The back pads are good also.
2006-10-06 12:58:25 · 7 answers · asked by Mr. BIG 5 in Cars & Transportation ➔ Maintenance & Repairs
i own a repair shop,and there is a centering valve,or more better known as a proportioning valve that decides how much pressure goes to the front and the rear brakes,if it gets thrown out of balance it cuts off the majority of fluid that is supposed to go to the rear brakes this happens a lot when master cylinders are replaced on a vehicle,what causes it is people get in and mash down real hard on the pedal trying to bleed them out,it throws the valve completely off balance,you can put it in balance again,but you have to loosen the front bleeders and hit the pedal hard and hope it works,it may put it back in balance,,if it don't you will have to go to a junk yard or buy a new one,to get the brakes to centered out again,i have done the same thing by being in a hurry to get a job done,,don't worry though its fixable,,it will take 2 people to probably get the valve back in center,good luck with it,i hope this help,s,i have done this for 36 yrs,,you may also want to check the adjustment of the rear brakes also.
2006-10-06 13:20:16 · answer #1 · answered by dodge man 7 · 1⤊ 0⤋
If the brakes worked prior to the master cylinder going bad , this is what properly happened. Your doing this at home and two people are needed when bleeding. Ask for a friend to help on bleeding the lines. There are two ways of doing this. If only the master cylinder was installed, fill the master cylinder to proper level, put cap/cover on and have friend pump brake pedal several times and hold same. Now you loosen one line nut at mc till fluid bleeds freely and re tighten the nut. Have helper repeat. Do same on second line at mc and retighten. If still low pedal, then the wheel cylinders need to be bleed. Have helper pump pedal, hold and you bleed the cylinders the same way you did the mc. replenish brake fluid and secure the cap/cover. If you have to adjust rear brakes, do not over tighten the hand brake cable or adjusters. Note: some replacement master cylinders come with a push rod. make sure the replacement rod is the same length as the old rod.
2006-10-06 13:45:56 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Proportion valve might be bad. Sure you adjusted them properly, bled them right (CORRECTLY), put the vacuum line back on the master cylinder and checked the check valve, checked brake lines for any possible leaks, and did you replace or rebuild the master cylinder (has to be rebuilt correctly)? Not very complicated and can only be a couple of things. Go back and re-check! Make sure you bled the brakes correctly! You have to start on the furthest and work to the closest from the master cylinder. You also have to pump them hard, hold the pedal while you "OPEN and CLOSE" the bleeder doing this several times until all the air is out! Make sure you used the right fluid also!
2006-10-06 13:10:20 · answer #3 · answered by Anonymous · 1⤊ 0⤋
When replacing a master cylinder it is important that you bleed the air out of it before you connect the front and back brake lines. the front brakes will work because they are directly below the master cylinder and air will rise to the top. Follow the directions on bleeding the Master cylinder before installing it in the car or you will have an air lock in the new cylinder.
2006-10-06 13:25:43 · answer #4 · answered by apache_ah64d 1 · 0⤊ 0⤋
Is there an anti lock up valve with the rear brake lines hooked to it and spring hooked to the rear differential? Rear shoes adjusted until you could not turn the wheel and backed off three clicks? Leading and trailing shoes correctly placed? 2006 trucks 4.0 liter V-6 265hp! or 2.5 liter 175hp! are waiting at your nissan dealer. There are Mexicans ready to haul old paint 720 Hardbody to Mexico for $2,500 good down payment before you spend anymore for new rear drums. Year end sale going on NOW!
2006-10-06 13:12:39 · answer #5 · answered by John Paul 7 · 1⤊ 0⤋
make sure your adjuster is working. if it is adjust the breaks tighter. there should be a rubber plug in the backing plate at the bottom and you use a flat blade screw driver or drum break adjusting tool and tighten it up some. also if you go in revise and stop some what hard that will also make the drums adjust tighter, you will hear them click.
2006-10-06 13:04:46 · answer #6 · answered by mustang656 4 · 1⤊ 0⤋
try adjusting the rear brakes. One way to see if they are not adjusted is to apply the park brake...if it goes all the way down then adjust the rear brakes this should fix the problem
2006-10-06 13:06:02 · answer #7 · answered by Kenneth S 5 · 1⤊ 0⤋