car - 91 civic wagovan awd

new rear wheel cylinders
new brake lines and fluid
new front brake pads

rear shoes are low but are adjusted tight

master cyl does not appear to leak
brake booster shoes no signs of a vac leak

no matter how much i bleed the system the car has barely any brakes when running. you have to pump them twice while driving before they start to do anything. is this a telltale sign of brake booster or master cyl? or do i just have some air stuck in the lines somewhere? there is no loss of fluid or any leaks or anything like that. could this be the shoes are to low?

i have the car for sale so id like to get this fixed and stopped spending money on it. if anyone has any helpful info let me know.

 

Sounds like air in your system.

 

This is a typical sign of a master cylinder issue -OR- air in the lines.

Did you bleed the brakes in the proper sequence?
(Passenger rear, driver front, driver rear, passenger front)

Which fluid lines did you change out - rigid or the flexible?
How much fluid did you let out of the system when you changed the lines?
If you let out enough fluid it might be possible that you got an air bubble into the master cylinder and you will need to bench bleed it out.

 

pretty much all the fluid was out, all the hardlines were replacing even the ones that run through the car.

the sequence i bled was pass rear, driver rear, pass front, driver front.

bench bleed the mc? im not sure what you mean by that.

thanks for the info dudes!

 

bench bleed is when you put brake fluid in the master and bleed it BEFORE you install it

 

Is your booster good???

 

His problems have nothing to do with the booster.

 

i bought a master cylinder bleeder kit and i did that and got all the bubbles out. i reinstalled and bled the entire system in the sequence suggested. it is somewhat better but still has a very low pedal when the car is running but gets hard with one or 2 pumps. sucky

 

You said something new now... you said the pedal is low when the car is running.
Is the pedal physically sinking towards the floor of the car when you start the engine OR is it just getting squishy?
The brake booster acts like power steering. Your brake pedal should be easier to press down when the engine is running.

Do you have to push the pedal down twice (like you say you do) to get the car to stop properly?
If you pump the brakes and just hold the pedal down, does it slowly sink towards the floor (requiring you to pump it a few times to get 'stiffness' again)?
If you are sure to have bled the MC properly and there is no air in left in the system
AND
it's not holding stiffness then it's highly likely that you need a new MC. Not holding pressure suggests that the seals in the MC are failing and fluid is getting passed them requiring you to pump the brakes.

 

yes it has changed, from no pedal while running to low pedal while running but if you pump it a few times while running its fine. while driving you need to double pump it for it to stop correctly. i did not notice any fading but. its drivable just not what it should be and im interested in fixing it since i have it for sale.

im pretty sure i bled the mc correctly. i did it with it in the car and pumped until there was no bubbles coming into the resevoir. i did notice the fluid drained when i pulled the bleeder fittings off the master and reinstalled the brake lines.

you guys have been a big help so far.

 

Oh boy...

You NEVER pump the brakes when bleeding. Your brake system is full of air now, haha.

You either need a vaccum pump or a second person to bleed your brakes. You bleed them from the bleeder valve on the brakes themselves.

http://www.popularmechanics.com/auto...o/4213448.html

 

oh really? have you ever bench bled a master cylinder?

of course i didnt pump while bleeding at the calipers/cylinders. look up the procedure to bench bleeding a master cylinder like i did to find out how to do it.

 

also the pedal always rose up, never stayed down. with the orig prob it would just shoot right to the floor and the brakes would not work, if you let off they would come back up though.

 

Eighty-Nyne either doesn't know what he's talking about or didn't read that you are doing a master cylinder and have the bleeder kit on.
Disregard his post... it's useless.

The problem with bleeding the MC in the car is that you can't really make sure the MC is level like you are supposed to.
It's very possible that you still have an air bubble.

Other things that come to mind:
- Block the front wheels and lift the back end up. Pull the hand brake 3 clicks. Spin the rear wheels. The brakes should be dragging lightly. If they are not dragging then they weren't adjusted properly.
- Remove the drums and inspect the brake cylinders for any fluid leaking. Blow rear cylinders are common with the Civic/CRX drums.
- When you bled at the wheels, how are you doing it? Are you getting help or using a 'one-man' bleed kit? ... or are you doing some other method?

 

If you replaced all lines,and you bled the lines at the master cylinder and the wheels. I never saw you mention you bled all the lines directly on the proportioning valve. Did you do that as well? If not that is the source of your air bubble/bubbles.

 

i did not bleed at the prop valve, also i did replace one of the lines that was coming off of the prop valve. so just bleed them as if i were bleeding a caliper? have someone apply pressure to the brake pedal while i crack each line?

 

That is correct. Have some one pumps the brakes. then have them hold pressure while you crack each line individually.

 

i checked the wheel cylinders and they are still good, and also brand new i put them in 2 days ago.

im bleeding them with a friend doing the pump pump pump hold method with the sequence you suggested. i really think i just have an air bubble still since i failed to notice the having the MC perfectly level thing. im gonna give it a once over one more time.

 

4drEF has given some good suggestions,
But one of the common cases can also be a seized brake caliper..

If the brake caliper is seized on the guide pins and not allowed to "float"
or move freely back and forth,It can cause the symptoms described..

I have replaced master cylinders,boosters etc..just to find the problem described above..

 

First: How was the brakes before the repair and why was it repair?
Second: It's possible that any new or rebuild part could be defective.
a. If rear wheel cylinders are defective new or old it will suck in air when you are pumping the brake pedal and will not bleed.

b. Make sure that the brake calipers and wheel cylinders bleeder screw is mounted and position at the highest point of each components.

c. Cracked the proportion valve lines to make sure fluid is coming out of there.

d. Bleed old brake fluid into a bottle submerge with a hose from the bleed screw so air can not get in when pumping brake pedal.

 

jalepanos22 speaks truth with statement d. Use this technique-- with the line cracked pump the pedal back and forth, making sure the MC does not go dry; followed by the standard-- one guy pumps up the pressure with the brake pedal while you crack the bleeder. Re-tighten the bleeder valve before pedal pushers foot lifts. Repeat this until you get only a solid stream.. no splurts.. starting at the bleeder farthest from your master cylinder and working your way closer...The set up mentioned in step d can easily be made from a piece of vacuum hose and a bottle of DOT3.. do work son..

 

No one mentioned a check valve for the booster, so I just did.
OP really didn't mention why all the brake stuff was replaced. If it was to fix a similar problem to this (and these parts didn't fix the issue), it could very well be something to do with the booster (as someone up above mentioned).

I mean manifold vacuum, or lack of, would easily explain the difference from engine running to engine off, wouldn't it?