Braking Problems

[AcMav]

I currently own a 99' I30t with 51,000 Miles on it and as of recently, within the last 500 miles or so, have been having some severe problems under hard braking. My brakes work fine at low speeds and normal street stops, but a few weeks ago someone stopped short in front of me and I had to jam the brakes. The brakes performed so poorly I had to swerve to avoid the car in front of me, I thought I was going to crash because my breaks just weren't stopping me; the tires did not lock, there was no ungodly noise, I just wasn't slowing down as fast as I used to or would expect to. I let my father drive the car as well and test it under stressful conditions and he agrees that the brakes just don't seem to have the same stopping power that they used to (he was the previous owner of the car).

All the work on this car has either been done by myself, or by the Infiniti dealership, the only after market part in the car is a K&N Air filter, the brakes are completely stock (The pads have been replaced within the life time of the car, I'm not sure about the discs).

I've check to make sure my tires aren't bald, I ran the test for the break booster in the Infiniti owners manual and I've checked the level of the brake fluid in the reservoir. The pads seem to be fine (No squeaking) and the discs look perfectly normal (They aren't warped). The pedal seems to feel the same as it did before, not spongy or anything. No idiot lights are on (I was hoping the ABS light would be on), I tried locking up the tires as well and they wont, showing the ABS is still functional to some point. I've never encountered a problem like this and to be honest, I'm stumped.

Please Help Me!!! I Don't feel comfortable driving my I30 anymore and I used to love it!

Much Thanks, AcMav

[91maximavg30]

have you bled the brakes?is there any brake fluid leakage? if so check the brake caliper piston seals.

[AcMav]

Thanks for the reply Maxi, but no, there is no leakage to my knowledge (Driveway under the car is clean) The Booster is also clean so the leakage would be occurring at the calipers, however they looked fine (I cleaned the car today).

I have not bled the breaks because the pedal doesn't feel spongey at all, the breaks feel exactly the same except for when I try to use them hard, leading me to believe its an electrical problem with the ABS in which it is overreacting (I could be way off here, I'm no car pro). Should i bleed them anyways? Thanks again
Modified by AcMav at 12:54 AM 1/14/2008

[MaximA32]

I would take a look at the brakes and see what kind of life you have left on the pads. How long would you say it has been since the last time they were changed?

[91maximavg30]

have the ABS checked out and if everything is ok then bleed them to be sure

[AcMav]

I'm pretty sure the pads are fine, there is no noise from the pads at all during operation of the car. This is definitely a TCS/ABS or Air in the lines problem. I just got out the good ol' Infiniti CD on the I30t and they say for a long stopping distance to Disconnect the ABS Solenoid and see if the stopping distance is still long. If it is, then the brakes need to be bled, If not, then theres Electrical Issues I hope its not the second, I'm not a fan of chasing electrical gremlins. Sadly we're getting a major snow storm here, so I don't know how comfortable I feel about disconnecting the ABS. I'd just like to say thanks for the help guys, I'm really glad I came here, and I'm thinking I should stick around. You know how to make a man feel welcome.

[MaximA32]

Not a problem. I have a quick point though. Just because the brakes aren't making any noise doesn't mean they are fine. Many brake problems don't present themselves with a noise until it's too late. Oh yeah, welcome to NICO.

[AcMav]

Yeah I know what you mean, Is there an easy way of checking the pads other than removing them? I know they've been replaced at least once within the life of the vehicle.

[MaximA32]

You should be able to take a peek at them with just the wheel off. You'll be able to see the inboard and outboard pads with just some light.

[AcMav]

If its not too cold tomorrow I'll check the pads, If not the pads then I'll test the brakes with ABS off and see what happens. I'll let you guys know, thanks for the help!

[AcMav]

Well since it was so cold and crappy today, I did the easy thing and pulled the ABS Solenoid Fuse, disabling the ABS system. Driving on icy roads and snowy surfaces the car felt like it braked much better than it did on Dry surfaces with the ABS enabled which leads me to believe one of the Abs sensors or the Abs computer is malfunctioning or has a loose connector. As soon as it warms up I'm going to check over the entire ABS system, Until then... who needs ABS anyways?

[Sentientbydesign]

I was under the impression that a thump thump thump happened when ABS kicked in. Am I wrong?

Also, you may have glazed pads and/or rotors. I know mine are because of stopping from 110 down to 20 when racing with a prelude.

[AcMav]

It did, and My ABS was working, the issue was it felt like it wasn't letting the brakes grip enough. ABS Works by letting the tires slip some so they don't lock up (Same as pumping the brakes), I felt my ABS system was managing the brakes too much and keeping them from stopping me, It was a sudden thing, so I'm guessing one of the sensors has a loose wire or something from me going over a bump, I'm just waiting till it warms up to check.