Brakes on a 97 Civic

Page 1 of 2  
Hi Group, I have a question in regards to the brake pedal on my 97 Civic. It has front disc, and rear drums. I have had the car for six months now, and
the brake pedal has always been low. It stops just about an inch or two above the floor. The pedal is not spongy, I have bleed the hell out of it, has at least 50% left of pads and shoes, I even replaced the master cylinder. The flex lines are good, no expansion. The brakes work fine, it just has a very low pedal. If anyone can shed some light on this, I would really appreciate it.
Thanks, Weldon
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/08/2010 07:07 PM, wjcimbri wrote:

are the brake drums self-adjusting properly? can you hear them click when you back them off, then pump with the brake pedal?
if you replaced the master cylinder, is the travel the same as it was before?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Yes, the rear brakes are self adjusting, and they are adjusted properly. The travel is the same with the new master cylinder.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/08/2010 07:49 PM, wjcimbri wrote:

i'll take your word for it, but how do you know? what did you check?

in inches, how much travel before the brakes start to engage?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I removed the drums and checked the hardware, and verified the drag on the drum.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/09/2010 06:42 PM, wjcimbri wrote:

there shouldn't be any drag on the drum when properly adjusted. if the threads on the adjuster screw are rusted or even greased, they can fail to self-adjust. i recommend removal, cleaning, refitting, then checking operation.
to check operation, reassemble screwed all the way in, then when reassembled, press on the brake pedal 20 times. each time you release, you should hear the self-adjuster click. then remove the drum again and be sure you can see the adjuster has screwed itself out a few mm. if it has, reassemble and pump the pedal until the clicking stops. you then should be good. if not, you need to clean and reassemble again. no grease.
what is the pedal travel before engagement?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have LOTS to say on this one. but don't have the time just now to write it up.
In short, you have numersous problems.
--
Tegger

The Unofficial Honda/Acura FAQ
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Given that the front disk pads engage the rotors before the rear shoes engage the drum, and do 70-80% of the stopping, I think I would look elsewhere besides the rear drums for clues to this issue.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/11/2010 05:29 AM, Zorro_2k wrote:

actually, that's not true - the rears come on first, but the proportioning valve applies progressively more to the fronts as the pedal continues to be pressed.

other than air in the hydraulics, a problem with the hoses or some serious caliper misalignment, maladjusted rears are the only place where you can cause this kind of pedal travel.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

A low pedal is indicative of several problems, which may or may not be present in combination:
1) aftermarket pads (wrong friction-coefficient for your brakes); 2) pads not floating freely on their mount brackets; 3) calipers not floating freely on their pins; 4) one or more hydraulic pistons sticking in their bores; 5) rust buildup between caliper, pads, and squeal-shims; 6) persistent air bubble (usually in caliper); 7) misadjusted master cylinder pushrod.
Complete removal of air from the calipers is sometimes only possible by using the "turn and tap" method, with the caliper off the rotor. This usually only affects rear calipers though, which you don't have.
If you're looking for a "magic bullet" fix, you probably won't find one. Your brakes need a good going-over by someone who understands how brakes work.
--
Tegger

The Unofficial Honda/Acura FAQ
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/12/2010 10:53 AM, Tegger wrote:

while you are correct in theory on #7, it's almost never seen in practice and i personally think it inviting trouble to cite it as a cause. unless something is broken, which is not a calibration problem, the position on the original master cylinder never changes. and if the master cylinder is replaced with the correct one, the new one is the same also. imo, this should /not/ be on the list of "diy likely causes".

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It is _often_ seen when a master cylinder is replaced and the pushrod is not adjusted to suit.

It is a legitimate cause of a low pedal under certain circumstances.
Given that testing for that involves nothing more than pushing on the pedal with your fingertips, it's worth checking.
--
Tegger

The Unofficial Honda/Acura FAQ
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/13/2010 06:05 AM, Tegger wrote:

disagree. for straight replacement with the same master cylinder with the same part number, the internals are all identical. if they are identical, there is no reason to adjust the pushrod because the power servo doesn't change and neither does the pedal lever. the only possible reason to change the length of the pushrod is if the master cylinder internals are different [using a different cylinder] or if the pedal pivots are worn. if the latter, they should be replaced - the push rod should not be monkeyed with to compensate.

not through anything other than extreme wear or use of an incorrect/non-standard part. if the former, the parts should be replaced.

indeed, but with the above proviso.
we have seen the result of this here before - if people monkey with the pedal adjust, they can end up with the cylinder vent holes closed and the brakes come on as the system warms and expands. that is a serious safety issue.
--
nomina rutrum rutrum

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Provision for adjustment is built-in to the booster/MC connection for the single and sole purpose of matching two individual components that must work together precisely. Much like the throttle body and the Throttle Position Sensor.
This adjustment is necessary on account of manufacturing tolerances.
If you install a replacement MC (OEM or not), you MUST make sure the pushrod adjustment is correct.

Pedal height adjust is different from MC pushrod adjust.
--
Tegger

The Unofficial Honda/Acura FAQ
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/13/2010 03:58 PM, Tegger wrote:

indeed, and like the tps, it requires no further attention unless worn. and the only things that can wear are pivots/contact points, not the internals of the master cylinder.

absolutely, but that variance is in the pedal/welding, not the piston/cylinder assembly which is highly precise.

dude, with respect, every single master cylinder i have ever replaced [and there have been many] - with conforming oem - has had the resultant pedal travel be precisely as it was before - not surprising since hydraulic pistons don't wear.
really, if you have experienced difference between pistons, there has to be some kind of issue, it's not a simple adjustment thing.

height is a function of the stop tab. pushrod adjusts travel, and thus depression before the equalization valves are closed.
--
nomina rutrum rutrum

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tegger wrote:

You're wastin' your time with Beam. He's in a world by himself. A flat earther it appears..

Ditto my answer above.
JT
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tegger wrote:

Exactly. I can't even remember the number of times that I've had to re-adjust the pushrod due to low pedal concerns.

Absolutely. After the usual suspects are eliminated.
What must be remembered here is the human factor involved in cylinder manufacture/remanufacture. That factor always results in variations...
JT
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/13/2010 09:24 AM, Grumpy AuContraire wrote:

then there is something seriously wrong with your car dude. you need to fix the cause, not monkey with the symptoms. master cylinder brake pistons do not wear. once set, you do not need to "adjust" them.

no dude - there is ZERO human factor in their manufacture. these are all produced by highly consistent and accurate computerized machines. every single piston has consistency and accuracy you can't even /contemplate/ with your foot.

--
nomina rutrum rutrum

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
jim beam wrote:

My experience is on a number AND variety of vehicles. You lose once again.

Then you are seriously out of touch with reality. The above may be the single most stupid thing you have uttered.
JT
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/13/2010 09:33 PM, Grumpy AuContraire wrote:

oh, busted, dang-it. i confess grumpy, i've never touched a car or a braking system in my life. i have no clue about manufacturing or measuring tolerances either. and i know absolutely ZIPPO about hydraulics.

reality comes hard to some folk obviously...
--
nomina rutrum rutrum

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.