my 91 civic sedan is experiencing something a bit weird that I am not 100% confident on diagnosing.

brake lines/pads are all in excellent condition. No leaks or abnormal wear.

Brake booster - no rust or fluid anywhere.

Brake fluid = new

First pedal press while driving for a while without using brakes = sinks to 3/4 of the floor and brake pressure seems spongy/weak. Pedal is really light and easy to push. Almost as if I have no braking pressure.

Let go of brake pedal and re-depress pedal = tonnes of braking pressure.

Is my m/c bad or my brake booster?

My experiences from past cars that I've owned would suggest m/c but someone here please give me some tips b/c I would hate to replace the m/c to only find out that it was really the brake booster.

Nowhere is pedal effort difficult to depress.

Thanks

 

usually master cyl.. may car is doin this now...

 

lets hope that my stupid m/c isn't leaking fluid into my brake booster...

 

Also make sure your calipers are able
to "float" in/out on the mounting pins..

Some of the strangest brake problems I have ever dealt with,
the caliper was stuck on the pins and not able to apply equal pressure.

 

my civic did that. i just replaced the mc and booster and upgraded to the da's stuff
hella stoppage now

 

to me it sounds like air in your lines..., you did mention new brake fluid, were you able to bleed it good...

 

fixed it. It was a bad m/c. Brake booster paint got eaten away but otherwise all is good.

Thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stevescivic from other thread that was created on same problem &raquo;</TD></TR><TR><TD CLASS="quote">Well so I posted a question earlier this evening asking about a bad m/c and brake booster.

Well I took a peek under the hood with a light and it was very obvious that the m/c was leaking. Sadly I didn't catch it in time and it ate away a lot of the paint on my brake booster and even part of my engine bay's paint

To make a long story short I half *** repainted my brake booster with some tremclad rust paint after thoroughly cleaning the brake booster with plenty of brake cleaner and sandpapered the rusted areas and rough paint edges.

In the process of repainting the brake booster I used a heat gun on the highest setting to make the paint dry faster and I was drying the spot with concentrated heat where the m/c would bolt up to. Well I know for a fact that the brake booster had some pretty intense heat on it and after about 3 - 5 minutes of heating it up I noticed that it started smoking!

I quickly stopped and tried blowing cooler air on it but it was obvious that some light smoke was coming out of the brake booster hole. My question is: Are there any "meltable" components behind the front cover of the brake booster or do you guys think it was the grease that was on the brake booster shaft that plugs into the m/c?

After smoking for like 2 minutes I decided to start the car and let the engine pull air through the brake booster hole (where the m/c bolts onto) in hopes that the vacuum draw will cool the internals of the booster off quickly.

There isn't any visible signs of burning of the shaft or the exterior of the booster but now I'm worried that I may have really melted something inside. I re-installed the m/c and bled the brake system and it seems like the brakes are working very well.

Judging by the exploded diagram of the brake booster it doesn't appear that there is really anything on the front end of the booster that could easily melt from a heat gun.

Can anyone shed some light on my little mishap?

Thanks

</TD></TR></TABLE>

 

I guess you already know what the answer is. shakes head.....

 

yeah.... that blows that I smoked the booster. Brakes works great so I guess I wait and see if the brakes get harder and harder to press. Maybe I'll be lucky and won't have to change it out. I went to Honda today to ask how much a new one was.... $630 bucks! Looks like the local wreckers will be my new parts joint.

 

Just go to your local autoparts store and get a re-man unit.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mar778c &raquo;</TD></TR><TR><TD CLASS="quote">Just go to your local autoparts store and get a re-man unit.</TD></TR></TABLE>

 

I wanted to know if my brake booster is going bad on my 93 civic my brakes lock up from time to time

 

check all rubber lines as well. replace if external cracks.
Regards
Dave