ok folks., heres my deal,. some time ago i replaced my front break pads,now when i opend the calipers i for got to open the fluied resivou lid.,just used a caliper compression tool.,any wayafter replacement i notice,. i have normal breaking,. out the drivway but when i hit the road and come up to a light or behind someone,. i get scared /triped out cause the pedel will go down real far., like its not gonna stop but then manages to slow car down enough,. just gets scary., anyway,. should i try bleeding my front brakes? or will i need to bench bleed my master? how do i bleed the master?

 

BUMP Someone has godda have some clue?

 

Couldn't hurt to do a good 4 wheel bleed. If you have rear drums make sure the rears are adjusted properly. Make sure the M/C is full. How does the pedal feel other than low? Is it firm or does it feel like you are stepping on a wet sponge?

Sounds like the fronts might not be working and the rear is trying to do all the work.

 

yea kinda like a wet sponge but if i pump again i can get more pressure ,. but like it will be holdin firm then it will just let go scaring me then at the bottom of the peddle im able to get it to stop.,.,,.,.,.

 

bleed the brakes, there is air in the system.

 

Nasty old brake fluid with rust and corrosion fills the resevoir in the calipers. When you push the callipers open that nasty rusty corrosion filled fluid gets pushed into the master cylinder.

Find something to suck out the old brown stuff out of the rear resevoir in the master cylinder. The rear resevoir is what feeds the front brakes. Put good clean fresh DOT 3 or better brake fluid into the rear resevoir and bleed your front brakes. Bleed them until the nasty brown rusty corrosion filled brake fluid is out of the lines and callipers and all you see is nice clean fresh clear brake fluid.

By that time all the air bubble should be out also.

I would also start your car after you have bled the brakes once, and let the vacuum assist drive any remaining air out of the proportioning valve Then bleed the front brakes a second time. You may see some more air come out after the vacuum assist had used its greater force against the master cylinder and proportioning valve.

You should not need to bleed the rear brakes if you only worked on the front brakes. The front and back systems are completely seperate as far as brake fluid flow. The Proportioning valve does not allow fluid flow between the front and back braking systems unless it is broken/leaky. It does allow the pressure of one system to affect the other but that is by means of a movable center section that is also attached to your brake warning light system. If you want to put clean fluid through your back brakes that is ok, just be prepaired with lots of fresh brake fluid and lots of spare time to make sure you get new fluid all the way through the system.

I would recommend 3 people. One to push the brake pedal, one to keep the resevoir topped off, and one to be at the calliper/wheel cylinder to open and close the bleed nipple. Do not leave the resevoir open when you are pressing the brake pedal down as it will squirt brake fluid up out of the resevoir. The rubber seal that fits under the plastic resevoir cover is usually enough to keep that squirting contained. That way you do not need to keep popping those plastic tabs on and off repeatedly.

The other way if you want to do it your self is to either use clear plastic or glass bottles with clear hose that will fit over the bleed nipples. The clear hose lets you know when the fluid goes from brown to clear and also lets you see any air bubbles. You can let gravity flow the fluid out of the resevior into the bottles if you are patient. For this to work you need to have the top off of the resevoir to releive the vacuum that gravity creats at the fluid drains out the bleed nipples. Harbor Freight sells a bleed kit for about $3.00. Get two or 4 if you want to do all the wheels at once. The problem with their kit is you will be busy draining the bottles as they are not very big. 1 Quart mason jars with clear hose work better if you really want to make sure all new fluid is through the lines.

dzimmerm

 

dzimmerm .,,. yea what you say sounds exsactly right,. my fluied is really dirty,.I just swaped rear ends and bleeded them., fluied flows fine no problem back there., but ill def take you advice., thanks for taking the time to explain it like that., im thankfull.,,. Also i notice., when i had my lil bro pushing the break pedel in i could see the booster arch out evry time not a lol but is this normal??

 

I usually work by myself so I don't know if the arching out of the booster assembly is normal. I am guessing it might be as most braking is done with the engine running and the booster would be an active component then rather than just a passive middle man when you are working the brakes with the engine off.

I am really not sure though, hopefully someone else will chime in if they know better.

dzimmerm

 

Nothing unusual it is caused by some flex in the firewall.