spongy brake pedal after SS line install?

[xstar]

For you local guys that installed SS brake lines and bled the brakes afterwards.

Did your brake pedal feel change?

I didn't think it should change, but my brake pedal now feels spongy... the car will stop, but it requires a farther "step" than before. I can rebleed the brakes again...

essentially, what are the possible problems that I should be looking for? Please take a stab at it.

thanks,

- Alex

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[romanom]

Don't take this personal...but you let air in the system. You need rebleed. Spongy pedal feel comes from air in the system.

[mad-dog999]

Alex, you've got 2 choices for this. One is to go to a dealership and have them bleed the system for you. Or, you could go someplace VERY abandoned and VERY safe and do a few ABS induced stops, then re-bleed the brakes. The reason is this: there are actually 2 reseviors inside the ABS system. 1 each for opposite sides of the car. If at any point you pumped the fluid resevior dry, there are 2 reseviors in the ABS solenoid to get air out of as well. The only other suggestion I have is to bleed them by ABS resevior order, IE: pass. rear, THEN driver front, then driver rear, them pass. front.

To be honest, I never feel a change under normal braking condtions. It's when I stand on the brakes that it feels different. You don't get that "unsure" rubbery feeling. However, if you're getting the unsure feeling under normal braking, then it's probably air in the lines.

-John

[2OHOH2WRX]

Definitely air in the system (hopefully no other contaminants)...

[Snowphun]

Is this two resevoir system unique to Subbie? I've never had trouble bleeding ABS brakes the old fashion way: open each bleeder one at a time and have someone pump the pedal until I get clear fluid.

I haven't messed with either of my newer Subbies so it'd be good to know if I need to approach this differently.

Paul

[jamz]

Definitely air in there. When I did it, I had to bleed twice, and I might even do it again later. Bleeding it properly is a two person job, so you are welcome to come over and do it here some weekend. Or, find a random cute girl on the street and have her help you.

[Ginseng]

Alex,

You've got air in your lines. Be sure to tap the lines as you're doing the pumping. Also, make sure you don't empty the reservoir when you are bleeding one portion of line. No problems bleeding it the way the Haynes manual says. The traditional way.

After my Goodridge install, the brake pedal was clearly and noticeably firmer under all stages of activation but really outstanding when you put the pedal to the floor. It just stops like you stepped on a rock.

Wilkey

[romanom]

Originally posted by Snowphun
Is this two resevoir system unique to Subbie? I've never had trouble bleeding ABS brakes the old fashion way: open each bleeder one at a time and have someone pump the pedal until I get clear fluid.

I haven't messed with either of my newer Subbies so it'd be good to know if I need to approach this differently.

Paul

There is no resevoir in the ABS system. All cars (by law) have to have a dual circuit master cylinder in case one fails.

On passenger cars this 99% of the time a diagonal system which means that both circuits are of equal volume.

When bleeding the best pratice is to bleed the curcuit together. So for 99% of passenger cars (including Subaru) you want to do one front and the opposite rear together.



Xstar:

Did you allow the reservior on the master cylinder to empty? I hope not.




Just FYI-

At the factory this is how it's done. They do it all one shot.

First you mount the Evac-Fill head unit to the res then all air is evacuated from the system, creating a vacuum. Then fluid is forced through the system at high pressure.

Then the car is delivered and people bitch about mushy pedal!

Just some more stuff:

I e-mailed a Tech at Ford I used to work with on the proper bleed sequence. Since techs do these all the time and engineers don't I'll take his advice.

This is it:

Doing nearest or most distant doesn't matter. What matters is if the brake system is a diagonal or front-rear system.

quick definition: diagonal means that one circuit in the master cylinder feeds the front driver's side and the rear passenger side. The other circuit the front passenger's and rear driver's. Both circuits are of equal volume. Front-Rear means that one circuit supplies the front calipers, while the other the rear calipers. The Primary circuit (front caliper circuit) is of greater volume.

All you need to do is make sure you do the circuits together. For instance, on most passenger cars it's a diagonal system. So you want to do the driver's front and passenger's rear together, which you do first is not all that important. But he does agree that the tradition is do to the rear first. Or best to get a friend and do both at the same time. And take your time (he told me to make sure I added this).

Same holds true for the Front-Rear systems. Do fronts together and rears together. Usually only trucks, SUVs and very heavy front bias cars (Ford Crown Vic) have a Front-Rear system.


Just FYI- Diagonal is used so that if one circuit fails the vehicle is still stoppable in a stable manner as at least one front and rear wheel is braking and on oppisite sides. Front-Rears are used as heavy, front-bias cars require a lot of volume up front.

[xstar]

thanks to everyone who responded.

I would do the bleeding process again. The reason I asked is that I had Exeter Subaru do the install for me... (well, at least the last 2 brake lines) The lady at the service counter assured me that the brakes were bled after the lines were installed...

Then I drove home not sure whether this spongy feeling would go away (I assumed it would). But it didn't...

The good news is that the brakes work well enough to be safe, I made it home okay. I sure didn't feel safe on my way home.

I'll bleed them all properly right now, once again.

thanks again to all!

[bill harvey]

I saw Brian bleeding them but i guess not well enough i will kick him in the ass for you tomorrow

[Mumbles]

Alex,

since i'm in the area i can totally help you out with it. I work were we met so i'm free just about anytime. We don't have to jack the car or take a wheel off or anything either. So let me know.

Brendan

[paultg]

You can "crack the bleeders" overnight also and let the system gravity bleed I think. At least I use to do that on Non-bas older cars. Just put something neat the caliper to catch any fluid.

Paul G.

[xstar]

ok, update post.

I bled through another 1/2 L of super blue. No bubbles at all four corners. Brake pedal is now firm. After a test run with hard stops from 60 mph, "sponginess" is gone. I feel safe driving again.

It is odd b/c I didn't notice much (if any ) air bubbles at all when I bled the brakes just now. I guess it doesn't take much air in the fluid to soften the brake pedal.

bill, thanks for posting in the thread. Perhaps you guys at Exeter should take a test run with the customer's car after a brake line install. Some noobs might not understand what to expect... In my own "noob-ness", I wasn't fully sure if I should expect an initial soft brake feel...

Anyhow, no one or scoobies were hurt. So that's good.

Thanks again everyone! I really appreciate all of your help.

- Alex

[sorbee711]

xstar,
Given that you have a WRX wagon (my future vehicle) and have done the SS brake line switch (one of my first intended mods) I was wondering what your impressions were on the differences. Can you post a bit about pedal feel, stopping distances, etc please?

Thanks.
Jeff

[twlai]

xstar,

I had the same problem with Exeter, and I went back
and they rebleed the system. Now is fine.

The pedal is really really firm now! Maybe a bit too sensitive

what do you think??

[twlai]

xstar,

I had the same problem with Exeter, and I went back
and they rebleed the system. Now is fine.

You may not see the air buddle because air could be
the first thing that come up of the valve, then follow by the
brake fuild.

The pedal is really really firm now! Maybe a bit too sensitive

what do you think??

[xstar]

sorbee711: The brake pedal feels firm now. But after an hour driving with a soft pedal, anything better is alot better. Honestly, the pedal feels about the same to me. I do alot of city driving, so I am partially on the brake often. However, hard stops felt good. I feel confident that the car can stop hard if I need it to. I'll be at BMW-Boston's autox school this weekend, so i'll test the braking ability more then.

Nonetheless, I thought SS brake lines + DOT4 fluid will resist fade, after hard driving, better than oem. That's why I got the set up. So I didn't expect a drastic improvement on brake feel...

twlai: maybe my feet are just lacking the nerve endings you guys got. The pedal feels about the same...

[jsnow]

Originally posted by jamz
Or, find a random cute girl on the street and have her help you.

"Will you push my pedal?"

I've tried that. It doesn't work.

[Snowphun]

A recently as a few years ago, ss brake lines were discouraged for street cars, as they need to be looked after to make sure the ss braiding doesn't fray and puncture the rubber hose. Just wondering if the manufacturing process is different now so that this isn't an issue?

Paul

[re92]

alex you have air in your brakes

raj
(smack my raj up)

[jblaine]

I fricking removed ONE banjo bolt at one rear caliper today, turned the line a bit because it was mispositioned (SS install goof), and immediately re-screwed it.

I have about 10% stopping power now.

*sigh*

Guess what I get to do tomorrow morning!?

[xstar]

I'm a n00b.

[Mumbles]

wholly post from the dead!

[m750]

Jeff -
I bet you have air in the lines.
AO