Brakes stick on a 96 neon replaced master cylinder did not bleed brakes

Hi would seem like the internal seals in the master cylinder are letting fluid past, If after you have pumped it a couple of times if you just rest your foot on the peddle with slight pressure will it slowly go to the floor this is a sure sign, You need to replace or recondition the master cylinder

Ask those questions at a repair shop
Your son doesn't have the knowlegdge
to resolve
Replacing a master cylinder & bleeding brakes
more than once, tells me he is lost

When you replaced the master cylinder, did you bleed it before you hooked it up? It not then you will have to take it back off and bleed it first. Fill it with fluid and pump the plunger in and out until there is absolutely no air bubbles. you can get a couple short pieces of brake line and bend them so the fluid drains out of the cylinder and back in the resevoir. Just make sure to work slowly so the air bubbles go away before they get back into the cylinder.

Make sure your brake lines are tight on the master, a little looseness will let the system **** air back in. Also make sure they have the same kind of end. some are "bubble flared" and some are "double flared" and they can not be interchanged. Also make sure your bleeder screws at the wheels are tight.

If this doesn't help then I would pull the wheels and check the wheel cylinders to see if any of them are leaking, also the front calipers. Hope this helps.

Could be a couple of problems, bad master cylinder (not bench bled properly or bad seal out of the box, I have had a few like that), proportioning valve seal, brake line not tight/sealed properly sucking air into system,bad caliper. First of all, are you losing brake fluid along with your pedal? Need to know that first. If you are, try to find where you losing it from, you will find your problem. There can be absolutly NO leaks in a brake/hydraulic system. If not, check that all lines are tightly seated and nuts are quite tight using a line wrench to get proper torque. If so, you can replace the master cylinder again (take old one back to store for new one under warranty) and be sure to thoroughly bench bleed. When bench bleeding, take your time, do not push plunger in too quickly, use a SLOW steady push until ALL bubbles, no matter how small have been eliminated. Tapping on the bottom of the cylinder while bleeding will help remove trapped air. Even a very small amount of air will take forever to bleed out at the calipers. If cylinder/all calipers/lines appear to be right, I would suspect the proportioning valve is faulty. To find it, follow brake lines from master cylinder to where they go into the valve. Replace. Hope that helps.

Did you bench bleed the master cylinder? You should try bleeding the lines going to the master cylinder too, just bleed them same way you would a caliper, only your loosening the lines a bit, not a bleed screw. Then of course, for good measure, bleed each wheel.

Let me know how it turns out.

Does sound like you need a new master cylinder. On a 2000 you wont need to back bleed. You will just need to follow the instruction and bleed the master and all four points. you will probably need to bleed the ABS block and proportioning valve but only if they have bleeders on them.

I would first bleed the brakes again -- maybe there is still a small amount of air still in the lines. If this doesn't work and there is no visible leak, I would have to suspect the master cylinder is "leaking by" internally. A new one shouldn't be failing already, but it's happened before.

Did your mechanic use a DRB III or equivalent scanner before performing the bleeding procedure after installing the master cylinder? This is a requirement by the manufacturer (Chrysler) when bleeding the brake system.

sounds like the master cyclinder

Hi my name is Allen!

To change the rear wheel cylinders on your neon, first take the wheel and the drum off, next using the proper size line-wrench take the brakeline off the wheel cylinder, next take the spring off the upper part of the brake shoe and pry back on the upper part of the shoe's, this will give enough space to remove the wheel cylinder without taking all the other parts off the shoes, next, take the 2 bolts off the wheel cylinder that hold it into place and install the new one in reverse procedure.

Note: Do one side at a time, becuse this will make easier to bleed the system. once you have one side done with the drum back on and every thing tight, then you will need someone to help bleed the brakes.

Note: make sure you never run out of fluid in the master cylinder are you will have to start the bleed procedure all over again.

Note: Have the person helping you, pump the brakes 5 times then hold the brake pedal to the floor and make sure they hold it there until you have loosened the bleed nut and tightened it back up again, once you have done that, have them pump the brakes and hold it down again. Do this procedure several times making sure not to run out of fluid in the master cylinder. Once all the air is out of the system replace the other whell cylinder on the other side and bleed it the same way.

Note: make sure before bleeding the system that all components are completely installed, because if you try to bleed the system with the drums off and before placing the shoes back where they belong and installing the spring and drum the wheel cylinder parts will be pushed out of it.

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