TypeSH

Ok, pedal was sinking when stopped, and when the car was off so I got a new OEM MC, installed that but now the pedal has a good amount of empty, dead spot before it applies any pressure. I had also installed new SS brake lines while I was at it but I dont think it has anything to do with this. I did not bench bleed the MC, but I did sit and pump the pedal like 20-30 times per corner until pure fluid came out. Bled it, fired up the car and had that problem. I bled it again today but no luck, so I know its not air in the system. I'm not loosing fluid anywhere.


so the last thing I can think of is adjusting hte pushrod/pedal height... but here i have some weird situation.

There are two adjustments, the pedal height, and the pushrod length.

If i leave the pedal height and pushrod where it was previously (where it worked fine w/ the old bad MC and brakes), the pedal sinks an inch or inch and a half before it has any resistance.

if I adjust the pushrod in and leave the pedal height, i end up w/ no braking power what so ever. Like the brake pedal is stiff. I assume I might have adjusted it too far in. So i undo it slightly, but then that leads to the above problem.

Currently, I have the pushrod out, and i moved the pedal height all the way down, and the brakes are better. but the pedal still sinks about half an inch of light resistance (almost no brake power) before the brakes work. However, the brake pedal is really low and I don't like it at all.

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What is going on??? I want this to be at the stock pedal height, where my brakes work fine.

the only other symptom i can get is that when the pedal is all the way up, and the pushrod is loosely out, stepping on the pedal w/ the car on makes a "swish" sound behind the pedal.

When I turn the car off, it takes a pump or two (w/ swish sounds) and the pedal gets stiff and feels right. When sitting on the brakes and turning the car on, the pedal sinks immediately.

help?

SIMATIC

you to i guess. i had the same EXACT prob with my civic. there was a good amount of dead space by the time there was pressure on the pedal. I changed the master cylinder( prob didnt need to). i changed the calipers too cuz my old ones were bad. i didnt bench bleed the system but i bled the lines a few times. my friends father( a mechanic) said that if you dont bentch bleed the system, it will be hard to get rid of all the air. also keep in mind that if you have rear drums, those brakes must be adjusted b4 u bleed the lines. i finally brought the car to mechanic, he bledd the master and my brakes were good for a week and slowly the pedal began to go down again. if it felt good for a week, it cant be the booster, i doubt it( 127k) to liitle milage for the booster or MC to go. i got soo fed up and sold the car. bought my self a 98 accord . good luck, man. i wouldnt mess aorund with the push rod, cuz u have to fix the problem it self, not work ur way around it , by playin with the rod. i dont know what the problem could be, hope fully thiscan help.

r1emperor

When you installed the mc without bench bleeding and then pumped it 20 or 30 times you probably blew one of the internal seals (too much pedal travel). Solution: Return the mc and put the pushrod back to original adjustment. When installing the new mc, put it on the car (with fluid) and have a friend push the brakes once and hold it. Put your fingers over the holes and have your friend release. Then take your fingers off of the holes and have your friend push. Repeat this a couple of times until fluid shoot out of the master. After a good amount of fluid shoots out, have your friend hold the pedal down while you install the lines. This way is kind of messy without the bleeder kit, but it works.

SIMATIC

all b/c i didnt bench bleed the mc

r1emperor

yep

Nikolai

Is it necessary to replace the booster when isntalling a new MC? I'm having the "sinking pedal" symptom, so I'm trying to figure out what is necessary when I get out and find some good used parts.

Thanks,
Nick

JimBlake

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nikolai &raquo;</TD></TR><TR><TD CLASS="quote">Is it necessary to replace the booster when isntalling a new MC? ...</TD></TR></TABLE>
No. I fixed my sinking pedal with a new MC. The booster doesn't contribute to the sinking, it just helps you 'push harder' on the MC piston.

Now if your MC has been leaking alonside its shaft, filling up the booster with brake fluid, that's a whole different thing...