Check the following:
From:
http://chevyavalanchefanclub.com/cafcna/index.php/topic,125037.0.html
One of the most important things to check is to make sure that you are installing the correct rear rotors. There are two sizes on the 1500 Avalanche. The main way to tell is if you have the G80 code (LOCKING REAR END) you will take the lager of the two sizes. Take your old rear rotor with you when you go to buy parts or if you order them check before installing, the offset and the size needs to be exactly the same! The wrong rotors will fit but are offset wrong and cause things to wear and/or brake!
Yes, I know at least two member who put the wrong size rotors on the rear, their braking was bad and one of them had problems, I think that the piston come out of the caliper after it got a little wear on the pads. The other member I helped dignose the wrong rotor problem and he changed them out before it caused a problem. Like I said the best way is to compare and make sure that the rear rotors are exactly the same, offset and diameter.
Another most excellent post even if you are not interested in the Durastops, lots of info on the brakes and replacing them:
http://chevyavalanchefanclub.com/cafcna/index.php/topic,91097.0/all.html
02-04 have two sizes available
The 325/330 nightmare
Can someone comment on the 325/330 nightmare? I remember going through this when I replaced my rear rotors the first time. The rotors I had to go with appeared thicker (wider vent), but I don't remember if they were 325 or 330. Is there a rhyme or reason to this, based on VIN? I'd like to do this upgrade since it's time for new brakes, and would obviously like to get the right rotors the first time.
Many believe, myself included, that Z66/Z71 gives you the bigger rotors
Honestly, the best solution I know of is a visit to a dealer with your VIN to be sure, OR removing a rear rotor and measuring it. Thickness and diameter are different - not just the diameter
I believe the answer is that the 330mm rotors go on the rear ends that have a locker and the 325's go on all on all others. I will not bet the farm but it seems this way to me.........thoughts?
That would follow with Z66/Z71 having them, certainly
Following this logic I bought 320's as I have a plain old 1500 and of course when I took the rear wheel off I see 330's?
Does your Avalanche have a locker rear axle? It will have a code: G80 on the glove box door.........if so the logic is still in tact
Yes it does, I thought the lockers only came with special packages?
Nope, the locker can/could be ordered by itself but did come in the Z66 and the Z71 packages
the consensus on here is that a "Z71" should have the "G80" locking diff,and therefore has the larger rotors.i sell auto parts to garages daily and more often than not i have to send both sets. the big difference between the two rotors is their thickness.
56827 = 12.795 dia.,overall ht. 3.35, rotor thk .760
580165= 13.00 dia. overall ht 3.76, rotor thk. 1.20
Not necessarily.....the concensus around here is that the difference is the locker, if you have a locker rear end it takes the larger of the two available rotors. I have a 2 wheel drive Z66 and it takes the larger rear rotor
Oh, and it is not valid to state that rotors are the same between 2X2 and 4X4
It comes down to G80 (locker) equipped or not...with a locker the rotors are 5mm larger in diameter and slightly thicker as well than non locker Avs...
From mu research..
there are 2 rear calipers/rotor pad setup s on 1500 AVYS 2002-2006..
2 piston or 1 piston calipers which dicytate pads and rotors.
2 piston comes on those with the G80 locker rear end
The main thinking around here is the G80 rear end has the larger rear rotors. So are you then saying that you can look at the rear calipers and if it is a 2 picton (very easy to tell without even removing a wheel) you then need the larger rotor. If so that makes it very easy to help all of the members who are asking the question.......
Rock Auto on the other hand shows Raybestos parts for both...and both are different...
4X4 and 4X2 with G80 locker are 330mm diameter
Remainder are 325mm diameter
Well for '03 or '04 1500 cladded Z-71...with factory installed G80
I have yet to see dual piston rear calipers...still use the larger 330mm rear rotors though
He has the G80 locker he stated hence the 2 piston calipers and bigger rotors..
And another:
http://www.chevyavalanchefanclub.com/cafcna/index.php/topic,103403.0.html
on the EBC pads. I have them now (green stuff7000) and think they are great. Not sure how much better the rotors are than the Raybestos Police grade though.
