anyone else notice excessive brake pedal travel before the brakes engage... The car seems to stop fine, but the pedal sinks a little before they start to engage... like the friction point is a little lower on the pedal...

i replaced both front calipers with my swap, and bled the hell out of the brakes, so i'm certain there is no air in the system... i'd like some advice before i buy a master cyl and replace it.

My guess is it has something to do with adding extra rubber hoses in the mix. People say its that much of a difference when you replace with SS hoses then I would think adding an extra couple rubber ones would also be noticeable. Just speculation tho.

The caliper cylinder also bigger in volume than the old wheel cylinder so the brake proportioning is off.


1993 Pontiac Sunbird 3400V6

Mine did the same thing at the very first, now the engagement point is right up top.

My saturn used to do that. It would have low pedal for a bit after doing brakes then get higher. Also if you are running hawk pads, thats just how they are cold. Weak as @!#$, thats why all the ST cars that run hawk pads drive from staging to the start box heating up the brakes so that their first couple braking sections dont have a way lower pedal than the rest of their run.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer

Mine was slightly lower at first but it either adjusted up some or I got used to it.




Currently #4 in Ecotec Forced Induction horsepower ratings. 505.8 WHP 414WTQ!!!
Currently 3rd quickest Ecotec on the .org - 10.949 @ 131.50 MPH!!!

i replaced the master cyl due to the fact that the pedal was doing this before... (however i also had a stuck front caliper that prematurely ate up the outer pad)

i replaced both front calipers with the swap.

After bench bleeding the master, then bleeding the system with the master installed, the pedal initially felt a lot stiffer, however as soon as i tried to stop, it was the same old low pedal position. I checked and fully engaged, i can still get my other foot behind the pedal, so maybe its all in my head...

i have 350 miles on the calipers, pads and rotors now... I'll wait till 1000 miles... then i think i need to figure out what needs to be replaced... the only things left are the ABS module, the lines, and the proportioning valves

The pedal on my car feels the same as it did before the swap, as far as I can tell. It hasn't changed enough for me to be bothered by it anyway.

I believe it has something to do with the way the caliper readjusts itself after new pads are in.

Calipers with mechanical parking brake systems are much different than a regular caliper.


"Oil Leak ? What oil Leak ? Oh, Thats Just The Sweat From All The HorsePower!!"

Have you all noticed a large decrease in stopping distance after this swap? Just curious...

I'll throw my .
It could be that your Cavalier's old drum brakes were well adjusted that it caused a firm pedal feel... moreso than normal. And going to this new set up, gives it spongier feeling, as all the Saturn's brakes whether it being disc/drum or disc/disc had/have spongier brakes than the Js.
Also "Zs Z" respose sounds about right too. More rubber hoses has a better chance to expand causing longer pedal travel.
Ofcourse, this is all speculation if you got all the air out of the lines.



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-----The orginal Mr.Goodwrench on the JBO since 11/99-----

I noticed a decrease in stopping distance somewhat, but the main thing I noticed was alot less nose dive under hard braking.




Currently #4 in Ecotec Forced Induction horsepower ratings. 505.8 WHP 414WTQ!!!
Currently 3rd quickest Ecotec on the .org - 10.949 @ 131.50 MPH!!!

Roofy wrote:I noticed a decrease in stopping distance somewhat, but the main thing I noticed was alot less nose dive under hard braking.

That makes no sense. You nose dive because of weight transfer, weight transfer is proportional to how fast you're stopping. It should nose dive more, if you're stopping faster.

Kyle, something to try, might sound silly. If you jab the brakes quick get off for a fraction of a second and then hit the brakes again do you have a firm pedal?


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer

Leafy (Club Jeffie FEA man) wrote:

Roofy wrote:I noticed a decrease in stopping distance somewhat, but the main thing I noticed was alot less nose dive under hard braking.

That makes no sense. You nose dive because of weight transfer, weight transfer is proportional to how fast you're stopping. It should nose dive more, if you're stopping faster.

Kyle, something to try, might sound silly. If you jab the brakes quick get off for a fraction of a second and then hit the brakes again do you have a firm pedal?

What you wrote Leafy, sounds right on the surface however you have to take into account the increased stopping power of the disk set up. In the same way that e-brake will hold the car's suspension compressed or uncompressed it could in theory keep the tail from lifting as high during hard braking thus less nose dive. Maybe compared to brand new drums there is no difference in nose dive but since most of us had worn out drums then it would be a noticeable difference.

I have also noticed less nose dive on my Fire, and since the brakes are the only thing that changed this must be the cause. My drums were also completely worn out.

My .02


-I drive my car to work-

Mystic02VA (GME Chat) wrote:anyone else notice excessive brake pedal travel before the brakes engage... The car seems to stop fine, but the pedal sinks a little before they start to engage... like the friction point is a little lower on the pedal...

i replaced both front calipers with my swap, and bled the hell out of the brakes, so i'm certain there is no air in the system... i'd like some advice before i buy a master cyl and replace it.

My pedal is still softer than it was with the drums. However it progressed from mushy to significantly more firm over the course the last few weeks. After I first did the install the pedal would mush almost to the floor but a follow up pedal push would be firmer. I noticed that after a 1,200 mile road trip the pedal was more firm particularity after 15 miles of 10% downgrade. I think that the R calipers just need some time to settle, since this is the only think that would change brake feel.


-I drive my car to work-

If a second time one the brakes quickly after the first one is significantly harder, then you're getting pad kickback. Its either from the caliper not being true to the rotor (statically or from bracket flex in and out, it shouldnt do either, I ran the numbers) Or its from fluid drainback. I wouldnt expect fluid drainback because the caliper is lower than the master cylinder but you may somehow be getting suction. If thats the case a 2 psi anti drainback valve put in the brake line right after the abs module would fix it.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer

Hook up a scanner and bleed the abs module. That is about the only way to do it. But I am guessing that is a part of your problem.

basically yes... the pedal does gets stiffer the second time i press it... the car stops just like it should once it starts grabbing, and i can get my foot below the pedal when fully depressed...

The pedal felt almost identically bad prior to the swap... however, i had two stuck front calipers, the driver side was stuck so bad that it cracked the inner pad in half and wore the outer pad to nothing (over the course of a month since i inspected my car and noticed 3/32 of pad on the outer and 6/32 on the inner)

while doing the swap, i replaced both front calipers, pad, and rotors. the pedal felt the same, so i replaced the master cyl (which was filled with dark liquid... it took a while to clean it all out of the reservoir)

The pedal felt a lot firmer while bleeding the brakes this go around, but it still sank as soon as i started driving and trying to stop. My co-worker theorized that since i now have rear discs brakes, the proportioning valve is off and created a lower pedal condition.

with 350 miles on the car now, i think its starting to stiffen up... but it could be in my head...

Another thing to consider... these calipers have a ratcheting adjustment for the e-brake that also brings the pads closer to the rotor to adjust for wear. Once they come out they wont go back in without turning. (Think of how our timing chain tensioners, or a jackstand operate). The pads probably need to "wear in" slightly to come as close as possible to the rotor and bring pedal travel back to normal. If needed i can whip something up in MS Paint if visuals are wanted.

Another thing that you can do that might help would be to fully engage the e-brake, rebleed the rear brakes, then pump repeatedly. This can also quicken readjustment to get proper pad to rotor spacing.




Currently #4 in Ecotec Forced Induction horsepower ratings. 505.8 WHP 414WTQ!!!
Currently 3rd quickest Ecotec on the .org - 10.949 @ 131.50 MPH!!!

500 miles on brakes now.... i attempted to rebleed the entire system, i ran the resivior from max to min on each corner, the pedal felt real stiff when i got in the car to back it out of the bay. when i drove and hit the brakes, the pedal sunk again...

i can still get a foot behind the pedal when its all the way down, and if i pump the brakes, it gets stiff right near the top, then sinks back again...

in the back parking lot, i brought the car to 50mph on wet pavement, and slammed on the brakes... the pedal sunk low, but the car stopped and the ABS Engaged and the car stopped on a dime... (i had plenty of space to do this, we have the length of three big dealerships and the width of 6 rows of parking spaces, all empty)

It seems my only problem is a low pedal... it just doesn't feel right...

The only thing i can think of at this point is either a) i have a bad proportioning valve, or b) the ABS has an air bleeding procedure that i don't know about...

ideas?

Sounds like a bad master cylinder or prop valve.




Currently #4 in Ecotec Forced Induction horsepower ratings. 505.8 WHP 414WTQ!!!
Currently 3rd quickest Ecotec on the .org - 10.949 @ 131.50 MPH!!!

i hope i didn't get a bad master cyl out of the box...

i guess i'll order a proportioning valve today and replace that and see what happens...


Edited 1 time(s). Last edited Wednesday, October 19, 2011 4:17 AM

Don't forget you also added a length of EXTRA rubber hose to the mix, you basically doubled the rears ability to expand and cause the low pedal feeling.


"Oil Leak ? What oil Leak ? Oh, Thats Just The Sweat From All The HorsePower!!"

That's either a bad master or pad kickback.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer

Im thinking pad kick back....

The master has been replaced and the issue never changed... i found my saturn rear inner pads were backwards (the squealer faced up instead of down). I switched them, but with no effect.

Ive noticed that:
1) if i hit the brakes with the car off or not moving, the pedal is normal
2) if i hit the brakes in reverse, the pedal is normal, once it was slightly soft)
3) While moving at any speed. If i tap the brakes, and then tap again, and then brake, the pedal is normal.
4) It seems like when my car decides it wants to hold 3-4k RPM in between gears (because not having a cam position sensor pad on my cam makes it do stupid things on occasion), the pedal will travel to its lowest point
5) In all cases, the car does stop... i can almost relate this to when i had a spec clutch and it wanted to engage where it felt like... the brake pedal now engages where it feels like

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