View Full Version : I need new brakes
Geoff_Rex
06-21-2010, 09:30 AM
Hey guys, hoping someone here can offer some advice. I need new brake pads on the STI. I have HT10's, on the front and HP+ out back for lapping, but the peddle is very soft. They don't seem to overheat as the peddle never goes away, but they're just really soft right from the get-go. I have RBF600 fluid in and even with stainless lines, the peddle is the same.
What's the recommendation for new pads (probably front and rear, though I'd rather not have to swap both out every time) and where's the best place to buy them?
Thoughts? Relevant comments?
dubya_rx
06-21-2010, 10:17 AM
If they are soft from the start, do you think there is some air in the line? Could try a swap to ATE blue fluid then back to Motul to make sure you've swapped all the fluid.
And it's not pad knock back right?
Geoff_Rex
06-21-2010, 06:07 PM
What's pad "knock-back"?
I have RBF600 fluid, and it's been bled 2-3 times for various reasons over the past year, and it still feels the same.
And, the brakes are fine on the street when I put the HP+ pads back on.
nocturn
06-21-2010, 06:58 PM
does your sti suffer from a moving master brake cylinder? I thought I had air in my lines and it turns out my firewall was flexing and the whole master brake cylinder was moving with it. Joe was pushing down on my pedal and I could see the MBC move towards the front of the car. That movement was creating my spongey brake pedal.
STeveD
06-21-2010, 09:32 PM
It wasn't the dealer who bled your lines was it? A local dealer to us doesn't believe in bleeding the inner nipples on the 4-pot / 2-pot.
Like Pete says, I'd address master cylinder flex. Cusco or Perrin should have (by now) a master cylinder brace for your car.
You shouldn't have bad knockback with your beefy front 5 x 114.3 bearings, but your rears might need work. To find out if you have pad knockback. Drive in a straight line. Brake. Note pedal height of the engagement point. Repeat a couple of times to memorize the engagement point.
Now, drive forward at slowish speed (20 to 40km/h should do) and throw the car hard left and right a few times without touching the brake. Now press the brake. If the brake pedal goes much deeper, you have flex on the rotor that's pushing the caliper pistons back into the housing. So the next time you try to brake, you first have to use the fluid to make up the distance from the recessed position to the point where they'll engage the brake. Then your second pump will generate full braking force.
You can manage this on the track by giving the brake a light tap with your left foot whenever you're approaching a heavy braking zone after some turn(s).
The brake booster engagement point can also be adjusted on the back of the brake pedal. Be careful with that... if you adjust it too far then the brakes will drag when the fluid gets hot. You need to be able to drive the car hard on the street, stop the car on a gentle slope with no parking brake, and the car should still roll easily.
Robin
06-21-2010, 09:49 PM
his car isn't right..... it's certainly something needs to addressed.... it's been bleed many times this year so doubt it's air in the system....
maybe the bracket might work but not the whole fix.....
STeveD
06-22-2010, 07:28 AM
Start with pad knockback analysis first then. It's possible that your OE front bearings have degraded with track heat.
Geoff_Rex
06-22-2010, 11:58 AM
Will do.
Thanks.
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