Hey guys,

I've searched the forum but cant find this exact issue. I'm really at the end of my rope and need some help to figure this out.

The brakes seem to work fine until you need to stop quickly. The pedal pressure feels fine, it never goes to the floor or anything, it just feels like at a certain pedal pressure the pads are gliding on the rotors. Unnerving when all the traffic comes to a stop on the highway in front of you. The pedal is not on the floor, I'm pushing hard enough to lock it up and relatively nothing is happening.

Speed of travel doesn't seem to matter either, 40 or 80 once the pedal pressure is high enough forget it. I can actually stop the car better with very light pedal pressure.

The first problem I had after replacing the rotors was a loud cyclical clunk, almost as if the caliper was striking the wheel at certain pedal pressure. I replaced those rotors and the loud clunking has now been replaced with weak to no braking power.

So far I've replaced the following:
all four pads, all four rotors, front calipers. Bled the brakes well, I do not think this is air in the lines.

Sorry for rambling, but can anybody help me? I'm at my wits end.

 

Try this first.

With the car off, pump the pedal. It should get hard as a rock. STAND on the pedal then and it should not go down at all. This means this is no air in the system (spongy pedal) and there is no leak or the MC is faulty (pedal sinks slowly)

With your foot on the brake, start the car, the pedal should sink meaning the vacuum booster is working properly.

Start with that.

What brand rotors did you replace yours with? Did you change your pads?

 

Thanks for your help. I will try this morning to test the vacuum booster and repost the results.

The rotors came from autozone unfortunately. I guess I misdiagnosed the noise I heard as a bad set that was slipping around the lugs. The pads are thermoquiets.

 

having new rotors and brakes should feel relatively weak at first. Usually new rotors have this coating on them to prevent them from corroding while in storage and i'm sure brake pads has it too for whatever reason. They should have at least a 500miles break-in period, if I'm not mistaken.

Also, to make things worst, autozone brake pads will have a weaker bite than OEMs....and along with the autozone rotors might reduce braking performance as well(compared to OEM). Optimal braking performance will gradually come but It might not be as you expect coming from OEMs.

 

How many miles are on the new rotors and pads?

 

I just changed all my rotors and pads and have been getting this chirping noise almost like a squeek everytime the DS wheel spins. It only happens after 5 mins of driving, can anybody help?

 

Did you apply brake pad grease to the pad contact points?

 

jrleslie......It sounds like you have a vaccum leak. Did you do any work under the hood? There is a directional vacuum tube that connects to the plenum, the one coming out on top on the passenger side. Check to make sure that is secured and there are no holes or cracks in it.

 

YA I did, there is only that chirping noise after 5 mins of driving. It doesn't make it when it rains though or after a car wash.

 

You should start a new thread instead of hijacking. Probably get better help too. I personally can't help with your issue, sorry.

 

Thanks JimNC,

I didn't want to say anything as I lurk here far more than I post.

I did what was suggested and pumped it up and stood on the pedal while I started it. I think the vac booster is functioning correctly. The pedal sinks a little but not to the floor.

I'll check the plenum for cracked hoses this afternoon.

Thanks for your thoughts everybody. I appreciate the help.

 

Sounds like everything is working as it should then. How many miles on the rotors and pads? Sounds like oyu may have glazed them over

 

mustang,

probably 1,000 miles on the set. If they are glazed it would be the second set of Thermoquiets to glaze on this set of rotors, I've replaced them once already. I know there are better pads out there, but these aren't duralast either. It's not "hard" to replace them, but its frustrating to keep buying parts to throw at the problem. That isn't being a mechanic, it's being a mathematician.

 

Any time you go aftermarket you're introducing variables into the braking system that Nissan didn't design in. The 04's especially, which came with the smaller rotors and calipers, relied on soft rotors and pads to stop the car quickly. They wear fast and dust a lot, but they work well. Many aftermarket pads are designed to wear longer, dust less and be quieter, but do not bite as well as OEM pads. Try going back to OEM pads and see if that doens't help.