Bled easily 6-7 times now with no improvement.. bled at the prop valve and ABS pump even.. also changed the MC.. nothing has worked.. there is pedal pressure, but I can pretty easily put it to the floor (it has been quite a bit firmer previously)..

Followed the helms and went LR -> RR -> RF -> LF in the bleeding order.. even did it once RR -> LR -> RF -> LF just to see if it helped and it didn't..

any thoughts?

I searched and saw something about bleeding with the car running, which I didn't do.. could this be the problem? I'd never heard of that until I saw that thread..

 

Have you tried re-bleeding after forcing the ABS to engage a few times?

I don't recall my pedal ever being soft enough to reach the floor, but each time my pedal's been softer than I'd like after a fluid change, this has cured it. Had to repeat the process a few times after installing SS brake lines, but it did fix it eventually.

 

that makes sense.. you need vacume to get full pedal travel.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by That’ll Leave A Mark &raquo;</TD></TR><TR><TD CLASS="quote">Have you tried re-bleeding after forcing the ABS to engage a few times?

I don't recall my pedal ever being soft enough to reach the floor, but each time my pedal's been softer than I'd like after a fluid change, this has cured it. Had to repeat the process a few times after installing SS brake lines, but it did fix it eventually.</TD></TR></TABLE>

yep.. been bled 2-3 times since then.. I'm still scratching my head about this..?

 

Have you checked the booster, (mastercylinder I think you call it in the US)

If you hold your foot on the brake pedal, does it slowly drop to the floor? If so then that is the culprit.

 

I've had not-great pedal pressure since the first day I tracked the car

My vote? Brake pads get a little warped, and springy/spongy. Never feel the same, and you don't get to keep "fresh" brake pads on a car.

Could be too much flex in the calipers too.

Dunno, I don't think there's a silver bullet. Did you ever suck air into your MC while bleeding? I did that once, flushed again, didn't really feel different afterwards.

Also I wonder about the brake fluid, maybe the racing stuff is spongy (Motul here). *shrug*

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Arsenal &raquo;</TD></TR><TR><TD CLASS="quote">Have you checked the booster, (mastercylinder I think you call it in the US)

If you hold your foot on the brake pedal, does it slowly drop to the floor? If so then that is the culprit.</TD></TR></TABLE>

the booster is something I haven't tried replacing yet.. with the car off, the pedal stays firm.. it's only with the car on that it gets spongy and can be pressed all the way down to the floor relatively easily.. not sure which you wanted to know..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chris F &raquo;</TD></TR><TR><TD CLASS="quote">I've had not-great pedal pressure since the first day I tracked the car

My vote? Brake pads get a little warped, and springy/spongy. Never feel the same, and you don't get to keep "fresh" brake pads on a car.

Could be too much flex in the calipers too.

Dunno, I don't think there's a silver bullet. Did you ever suck air into your MC while bleeding? I did that once, flushed again, didn't really feel different afterwards.

Also I wonder about the brake fluid, maybe the racing stuff is spongy (Motul here). *shrug*</TD></TR></TABLE>

well, once this started happening, I replaced the MC and bench bled it properly and all that so there shouldn't theoretically be any air in the MC. it was doing this same thing before and after the MC change with no improvement..

could pads being slightly warped change pedal feel? they looked alright visibly, but I guess that doesn't mean that they couldn't be warped a little.. I had used the pads a few track days before this started happening though..

one strange thing I noticed is that the LF seems to dust normally (a lot with these Spec-VR's), but the RF doesn't seem to be dusting as much.. unless it just wasn't coating the wheel like on the other side for some reason..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mstewar &raquo;</TD></TR><TR><TD CLASS="quote">one strange thing I noticed is that the LF seems to dust normally (a lot with these Spec-VR's), but the RF doesn't seem to be dusting as much.. unless it just wasn't coating the wheel like on the other side for some reason..</TD></TR></TABLE>

Interesting.

I run Spec VR's also and the right front (driver's side on my JDM ITR) makes noticeably more dust than the left front.

 

Brake booster could be culprit. I would expect that if it were a caliper piston seizing or getting hung up that the pedal would feel tighter not more loose. Worn pads shouldn't make the pedal travel more if the fluid is higher. The lower the fluid, the more pedal travel involved for braking that has been eliminated by keeping fluid high.

This will sound like an odd one, but check the rear pads to make sure that you have both seated in properly with the rear caliper pistons (little tab is fitting in the cross hatching). I've seen these not seated properly causing a 'weak spongy' feel before.

Hope this helps a little.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BudMan &raquo;</TD></TR><TR><TD CLASS="quote">Brake booster could be culprit. I would expect that if it were a caliper piston seizing or getting hung up that the pedal would feel tighter not more loose. Worn pads shouldn't make the pedal travel more if the fluid is higher. The lower the fluid, the more pedal travel involved for braking that has been eliminated by keeping fluid high.

This will sound like an odd one, but check the rear pads to make sure that you have both seated in properly with the rear caliper pistons (little tab is fitting in the cross hatching). I've seen these not seated properly causing a 'weak spongy' feel before.

Hope this helps a little. </TD></TR></TABLE>

hmm.. i really didn't want to replace the booster (hard to get to with the cage in there, but I'll give it a shot.. I'll check the rear pads as well, since I planned to replace them anyhow with something with a little less bite..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BudMan &raquo;</TD></TR><TR><TD CLASS="quote">Brake booster could be culprit.</TD></TR></TABLE>

I don't get it!

OK, spongy pedal means that the master cylinder is moving more than it should (i.e. there's some flex in the system, either air, caliper flex, brake pad flex/installation error).

How could the Brake Booster make it move more, besides applying an incorrect amount of "boost" which would make the brakes lock up faster?


I have NO idea what the problem/solution really is, but it doesn't feel to me like this is a BB issue.

-Chris

 

Wasn't there someone in RR/AX who battled spongy/iffy brakes for a year or more before they finally figured it out? I have no idea who it was or any hints to search on though

 

Mark-

FWIW, I've had a more "spongy" feel ever since I began using stainless lines. I've tried both the Russell and the Goodridge. I had the Goodridge in the H2 car, and I now have the Russell in the H1 car. Both feel about the same, and the pedal is never as firm as it was when I had the stock lines.

If you're that concerned about feel only in regards to pedal pressure, I'd suggest looking into a MC brace. I feel that although it leaves much desire in the form of modulation/overall feel, it definitely enhances the pressure of the brake pedal.

Good luck, and get down to CMP in two weeks

 

I'd love to attribute it to the SS lines (I use StopTechs), but this started well after having those for awhile and running multiple events with them..

maybe I should get an MC brace.. I think if you felt this though Jason, you'd say something was amiss though..

Pat, was it this thread?:
https://honda-tech.com/zerothread?id=1431381

they're talking about boiling fluid (which I know isn't the cause of this) and warped pads.. I went ahead and posted in that too.. or did you mean Anton's issues?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mstewar &raquo;</TD></TR><TR><TD CLASS="quote">I'd love to attribute it to the SS lines (I use StopTechs), but this started well after having those for awhile and running multiple events with them..

maybe I should get an MC brace.. I think if you felt this though Jason, you'd say something was amiss though..</TD></TR></TABLE>

I see. To add, the pedal pressure is the way I described immediately after a system flush. I'm not speaking of the pressure after half of a race.

If you were able to retain the stock pressure after installing the lines, then send that info my way

Good luck

 

try adjusting the booster

also, check wheel bearings/hubs (can cause brake issues)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mstewar &raquo;</TD></TR><TR><TD CLASS="quote">Pat, was it this thread?:
https://honda-tech.com/zerothread?id=1431381

they're talking about boiling fluid (which I know isn't the cause of this) and warped pads.. I went ahead and posted in that too.. or did you mean Anton's issues?</TD></TR></TABLE>

That one wasn't it, this one was at least 3+ pages. But that was too many frosty beverages ago

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Back in Black &raquo;</TD></TR><TR><TD CLASS="quote">

I see. To add, the pedal pressure is the way I described immediately after a system flush. I'm not speaking of the pressure after half of a race.

If you were able to retain the stock pressure after installing the lines, then send that info my way

Good luck </TD></TR></TABLE>

same here.. this is a "pre-race" problem, if you will.. the brakes are there and stop the car, but the pedal effort has decreased quite a bit and the point where they seem to be working is lower on the pedal..

but yeah, at least for awhile, the pedal would be stiff as I was used to after a good bleed after we had installed the lines.. then it stopped being that way.. shouldn't SS lines improve pedal pressure not decrease it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mstewar &raquo;</TD></TR><TR><TD CLASS="quote">but yeah, at least for awhile, the pedal would be stiff as I was used to after a good bleed after we had installed the lines.. then it stopped being that way.. shouldn't SS lines improve pedal pressure not decrease it?</TD></TR></TABLE>

To my understanding, they are more durable than the stock lines. Also, they generally will add more "feel", ie: modulation. Honestly, I've never heard of them claiming to increase pedal pressure.

 

I've had SS lines from Techna-fit for 5 years. My brake pedal has always been very firm. With the fluid as full as it can get in the MC, the pedal reacts very high in the pedal travel range. The higher it reacts, the easier it is to heel-toe.

I wish I had an answer for the problems. I've posted a few thoughts & my experience. Anytime we can catch up at a track, Mark & Jason - drive my car & see what you think. I haven't done anything special. The car has 125,00 miles on it. I just replaced the calipers over the winter & they feel just like the did.

Good luck. Keep us posted.

**as for the Brake booster being the problem. If you have anything that is attempting to increase hydrolic pressure - a small leak in the diaphram or other issue could cause the problem. I'm not a brake master - these are just my .02.

 

Sounds good, Jeff. I'll see you in Kershaw, SC in two weeks, LOL.

Seriously, I'd like to take you up on that offer

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Back in Black &raquo;</TD></TR><TR><TD CLASS="quote">Sounds good, Jeff. I'll see you in Kershaw, SC in two weeks, LOL.

Seriously, I'd like to take you up on that offer </TD></TR></TABLE>

You'll have to come a little farther west to drive the car. Gingerman, MAM & Heartland Park are the only tracks I'll be running this year.