PDA

View Full Version : Sponge Pedal Advice please.



Legacyofdan
04-27-2010, 02:56 PM
Alright after changing out my front calipers my pedal has gone soft and useless.
I bled the brakes after changing the front calipers, noticed a leak coming from my old stock master cylinder. So i replaced my master cylinder with a new one.

And then Bled my brakes rear passenger to rear driver to front passenger to front driver.

There are no more leaks any where, be it in a hard line, SS line or caliper, the calipers do compress a little bit now with the new master cylinder...but not enough to produce real braking power. With the vacuum assist(car on) the brakes feel softer than my clutch pedal.

i have gone through about 20 fl oz's worth of bleeding since the new master cylinder and i have not seen any bubbles come out of the clear tube...well with exception of the first couple of bleedings. but no more air comes out at all.

This is on a NON ABS ST165 4th gen 1988 Celica Alltrac(redundant alot there i know but just being clear). Stock rear calipers. Stock replacement Master Cylinder for an ST185(bolts up fine, same size, different sensor, but you can use the 165 sensor on the 185 reservoir thing). SS Brake lines all the way around. 2009 Tacoma 4 POT Two Piece Fixed front calipers....

Sooo this is not the first time i have had issues bleeding my brakes on this car, i have done it on several other vehicles and never had an issue...and i even had issues with red trac even with the stock front calipers..in fact i had very similar issues way back in the day and oddly enough over time they just sorta started to firm up...even though there was no visible bubbles coming out...


So what i am asking is for advice on what to do next do you guys believe that the master cylinder can build enough braking force to compress the front calipers? if that is the case, why are the rear stock brakes still crap too? since it should still be able to produce enough pressure to compress the rear brakes enough. but it doesn't.


Here is my procedure for bleeding brakes, two person style.

Person A pedal pumper/reservoir checker.
Person B Bleeder.

Person A pumps up pedal 5-7 times, holds pedal down as far as they can. Communicates that the pedal is held down. Person B loosens the bleeder nipple of which is attached to clear tube to watch for bubbles, once the line bleeds Person B then tightens the nipple and communicates to person A to pump up the lines again.

So yeah i think i provide all the necessary information...help me out please. :)

Legacyofdan
04-27-2010, 04:01 PM
Damnit i learned something today:
http://www.555club.com/articles/article18/article18.htm

Be sure to place the caliper with the bleeder valve on the top and not the bottom. If you don't you will not be able to properly bleed the brakes. Air will get trapped.

Tecker184
04-27-2010, 07:19 PM
wait 2009 Tacoma calipers up front? Is that a bolt on upgrade? what size wheel are you running? It could be possible that the OEM st185 master cylinder inst up to par. See if you can source a st205 master seeing how they had large brakes from the factory. It is also possible to install the calipers upside down not.

93celicaconv
04-27-2010, 09:12 PM
Did you bleed your new, replacement master cylinder before starting the process of bleeding the brake lines? Master cylinders need to be bled first.

Legacyofdan
04-27-2010, 09:46 PM
Here take a look at this thread about tacoma calipers on 165/185's:
http://www.alltrac.net/phpBB2/viewtopic.php?f=8&t=36769

and yeah when i install the calipers i got the sides switched, therefore air pockets developed in the outer two piston of each front caliper and were not bleeding correctly....basically i had a blonde moment. or in my case since i am a guy a dumbass moment.

and yes i did bleed after i got the new master cylinder, for go to mention my bad...

just got home from work now, and going to swap the calipers around and bleed again and that should do the trick...


OEM st185 master cylinder inst up to par.
there is a chance that it may not be beefy enough...but we will find out soon...