New rear brakes - longer stopping dist?

[jdizzle262]

Hi-

I recently had my rear disk brakes and rotors replaced on my 2001 Hyundai Sonata by Firestone (Wagner Thermoquiet Organic pads, Duralast rotors). I've noticed that when starting out and the brakes are cold, the stopping distance is much longer than it should be. After 5-10 stops, stopping distance is back to normal.

Any ideas as to what might be going on?
The brake fluid is getting close to requiring replacement based on copper content, but not quite there. They also mentioned that the left rear caliper pistons were really hard to retract (but I wouldn't think that would have anything to do with it).

Thanks much!

 

[Lead Shoes]

I would change the fluid and see if it gets better, otherwise your old pads may have been better...

 

[HTSS_TR]

Brake is like tire, it needs some driving distances/braking to bed in. After a couple hundreds miles it should be better.

 

[eljefino]

Originally Posted By: jdizzle262

The brake fluid is getting close to requiring replacement based on copper content, but not quite there.


I want to know more about this. Do they test it in-house?

 

[bdcardinal]

Originally Posted By: eljefino
Originally Posted By: jdizzle262

The brake fluid is getting close to requiring replacement based on copper content, but not quite there.


I want to know more about this. Do they test it in-house?

They sell test strips for brake fluid like for coolant. You dip it in and compare to a chart on the bottle. Only problem is those strips are HAZMAT in California.

 

[Carbon]

Originally Posted By: jdizzle262
They also mentioned that the left rear caliper pistons were really hard to retract (but I wouldn't think that would have anything to do with it).


After one inadequate stop after cold, park the car. Compare the temperatures of the two rear rotors. Compare the temperatures of the two front rotors. Do not use your finger, at least not until you first use a wet Q-tip where you listen for the sizzle. If you detect a noticeable difference in temperature, have the caliper at the cooler rotor repaired.

 

[jdizzle262]

Thanks for the tips. I'm thinking I will probably at least flush the brake fluid since it's going to need that in the near future anyway.

Yes, they use strips to test the brake fluid for copper content. This kind of thing: http://www.gwrauto.com/stripdip.htm

 

[garlicbreadman]

3 things:
1.cold brakes dont stop as well as hot......thats a given
2. brakes need to BED/break in before you see their full potential
3. never had organic brake pads, i assume they are not as good as semi metallics or ceramics since most car makers dont use them

 

[VK56VD]

I would give your brakes some time until they bed in. Rear brakes do little braking compared to the front brakes and usually take longer to bed in.

I would also do a complete brake flush or at least bleed each caliper.

 

[jdizzle262]

It has been a couple weeks and 700 miles or so since they were installed...

 

[ComfyShorts]

Originally Posted By: jdizzle262
Wagner Thermoquiet Organic pads.

Found your problem.

 

[mechtech2]

Actually, some brake pads stop BETTER when cold than hot.
This is identified by the rating on the pad [EE,EF,FF, etc..]
Give them time to seat, first.

 

[eljefino]

I'm suprised you feel anything. Always thought rear brakes gave 20-30% of the stopping force. If that were cut in half you'd only have a 15% reduction.

Maybe it's time for your front brakes to get checked out, too. They might have sticky hardware that transfers force rearwards, or glazed pads etc. On one hand if you get more wagner thermoquiets you'll be balanced, but if they really are a lousy pad will have more pedal effort. OTOH a nice pad will bring the balance forwards, for better or for worse.

 

[Virtuoso]

The last set of Organic pads I had stopped the car just fine.. they dusted like crazy [censored] though.

 

[Letter_K]

According to Wagner, the brake pads come in what the OE material was and according to O'Reilly, the OE material is ceramic.

Thermoquiets tend to be the premium pad sold by O'Reilly and Advance Auto after you go through their in-house brand line (Wearever or Brakebest.)

Eljefino may be right, but would imagine they should have checked the condition of the fronts too. Perhaps, one of the calipers is hanging up?

 

[jdizzle262]

Originally Posted By: Letter_K

Eljefino may be right, but would imagine they should have checked the condition of the fronts too. Perhaps, one of the calipers is hanging up?


They said the fronts were fine. I'll take it back to Firestone this weekend and have them take a look. Will let you know what I find out.