I replaced my rotors and pads on Sat with powerslot rotors and some akebono pro act pads.
Stopping improved.
Last night my friend was curious how much better the brakes were and wanted to try my car.
I let him.
He took a series of hard brakes till the fade set in, BUT eventually the brakes felt VERY spongy and had to depress down all they way and the stopping was very weak.
This morning its still very weak.
Is this an issue with bad rotor/pad break in or more a master cylinder/booster/air fluid issue?

 

Sorta sounds like air in the fluid, or maybe got hot enough to boil.

Unless you've just done this, I'd flush/bleed to get all fresh brake fluid in there. (moisture in old fluid results in lower boiling point)

 

The fluid is about 1yr old, so it wasn't bled or flushed.
I will be doing this on sat when i'm off work though.
I'm really afraid the rotors are messed up in some way due to bad break in.
Power slot says avoid hard stops till after the break in period.

 

rebleed the system and if that does not work and your lines are OK, replace master cylander (or rebuild it)

 

flush out your old fluid and replace with some good fluid, such as ATE super blue or MOTUL 600. if that doesnt solve your problem try SS lines or if things get serious, take a look at your master cylinder, but i doubt that.

since we're on the subject of brakes here, does anyone know if the accord has any problems with mastercylinder & firewall flex? i know the scion TCs had a common problem with that under hard braking conditions, the firewall would actually flex and cause a spongey brake feel.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pos_cd5 &raquo;</TD></TR><TR><TD CLASS="quote">since we're on the subject of brakes here, does anyone know if the accord has any problems with mastercylinder & firewall flex? </TD></TR></TABLE>

I believe there was a recall released by Toyota for that problem pertaining to the TC's, but i'm not 100% positive. I will get in touch with my guy over at our Scion/Toyota location to get the inside scope. No TSB's were released by Honda for this issue. I must admit I've never actually had a problem relating to master cylinders in any Honda. Quality product if you ask me.

 

actually, its not uncommon to see hondas mastercylinders needing replacing, but i think its all due to neglect. since mine only went out because my fluid was coffee brown and wasnt flushed for years and most likely corroded the seals.

 

valid point.....

firewall flex however is not an issue.

 

Did a Bleed, same deal.
How do you know when the master cylinder is bad?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bruce Banner &raquo;</TD></TR><TR><TD CLASS="quote">Did a Bleed, same deal.
How do you know when the master cylinder is bad?</TD></TR></TABLE>

when nothing else fixes the problem . its usually pretty obvious, excessive travel, sponginess, etc.

 

I very much doubt you damaged the rotors, powerslot rotors are extremely tough...i brake the crap out of them and when i took them in for resurfacing, the oreilly guys told me they barely needed to resurface it, in fact, they said the least they ever had shave off of rotors were the ones i brought in...

when you were modifying your brake system...you didnt let your brake lines hang the calipers right? you can have weak brake lines...or you could have bad seals in the calipers...check if anything is leaking and check if any of the lines are damaged

 

you probably glazed the pads. The reason that you need to take it easy on the brakes for the first few days is to the pads can set and mesh with the rotors, and the protective coating on the pads can wear out. Its not just performance brakes, its just brakes in general. we get dozens of customers coming back for the same reason.

you NEVER test your new brakes by doing 100mph and trying to stop in 6 feet, and this is why.

remove the brake pads, if they feel glossy, thats probably the problem. Get a sheet of sandpaper, put it grit side up on a flat surface, and sand the pads till they arent glossy anymore.

Once that is done, and if the problem still occurs, then inspect the brake lines for swelling. If they are spongy or swelled, replace them. if this still doesnt change anything, then its probably the master.

 

Some pressure to the brakes did come back today, with continued normal braking would that have the same effect as taking them out and sanding them?

 

eventuially, it will cut down to fresh pad. But let this be a lesson on babying new pads and rotors.

 

I guess that might explain why the pressure to the pedal came back a bit yesterday

 

could it be the booster or the VC?

 

I used the Akebono rebuilds with the Pro-Acts. Pro-Acts are HARD ceramic, and may make the brakes feel "weak" for a while. It takes a LONG time for the ceramic to seat to the rotors- be very patient! If the rotors were faulty, you would most likely have slight vibration at braking, due to them being warped.

Bleed the crap out of the system-be sure to follow the proper procedure in the manual with respect to when you bleed each "station", or you are wasting your time. Check for tightness/non-leaking at all the brakeline fittings. One can be loose enough to "backbleed" air and show almost no sign of leaking!

Run the manual test for the power-assist unit (simple if you have a good manual). If ALL above proove OK, run the tests for the master-unit. My guess is the master is old???

Last summer I completely rebuilt the system on my 94 (non-abs). Pads, rotors, new SS lines, all new hardware, it was gutted and replaced. The brakes were "spongy" after several bleedings, so I tested the power-assist (OK) and then the master. The master had been replaced, when I got jammed for time, by a shop about 20,000 miles earler, with a non-OEM unit. It was failing already! I bolted in a new OEM Honda unit, rebled the system, problem solved.

For almost 5000 miles the brakes felt slightly "weak". Then the front Pro-Acts and rear OEM Honda shoes (I have rear drums) finally seated- the Pro-Acts and OEM Honda shoes/pads are very hard ceramic (far long-life) and take a LONG time to fully seat.

A note for those with rear drums, when you rebuild. After about 3K miles, I checked the new OEM rear drums, and found the shoes were not seating properly. So I took them to a machine-shop and had them "cross-hatch" cut. After this, the shoes seated fast. I talked to a few brake-guys I know. They stated they see this with new OEM Honda drums (they are very smooth), and "if it was my car, I would have the new OEM drums cut before installing them". After 30 years, I still learn new stuff all the time- Wrenchy

 

How do I test for the master cylinder?

 

I think the issue is resolved.
Bled the system a few more times and installed steel lines.
Pressure is better then it has ever been.

 

what condition were your old rubber lines in when youre moved them?

 

Dunno, I didn't get a good look at them.
They were dirty that's for sure.
I don;t think they leaked.