Warped rotors / New Brakes - Questions

[ComputernerdBD]

Hey everyone. I am getting vibration/pulsation when I hit the brakes. I have decided based on my other thread, the hard spot when I spin the front left wheel, the vibration and noise that the rotors are warped. I have purchased the AC Delco OEM rotors (177-1007) and pads (171-0979). However I was less than impressed when I got them. The brakes had a ton of dust in the box and the rotors were completely painted a grey color. I considered buying the Akebono ceramic pads (ACT1169), but not sure if I should return the AC Delcos and buy these instead if they do not leave as much dust and provide better braking. Also with the painted rotors, what is with that? I have also considered the Powerstop brake kits with the drilled/slotted rotors, but as they seem to have a different cooling vane design, I was not sure. The other higher end pads/rotors seem to approach into the high performance market which as I do not race I would never be able to justify the higher cost. I seem to never have to replace pads on either of my trucks due to low pads, but failed calipers and/or rotor issues (warping/rust) before we even get to that point.


I have never done brakes before, but are they easy to do on these trucks? As long as I get the torque specs correct and follow the repair manual procedure, anything special specific to the Trailblazer? With the slider pins, how do I properly grease the slider pins? Do they come out with the caliper or are they separate from the bolt? Thanks

 

[Gerbil21]

I haven't don't front brakes on these trucks yet but they should be the same as the rear after taking the wheel off you need to take of 4 bolts 2 for the caliper and 2 for the bracket. Then you can pull the rotor and replace then. As far as I know the "paint" is a anti rust coating also most of the time regular rotors are just fine and there is no need for slotted or drilled rotors as far pads those are purely dependent on how you drive but ceramics are good.

Just remember to push in the caliper pistons with a large enough c clamp iirc I used a 3"clamp for the rear and use the old pad the push on. As for the pins, on the rear I just pulled the boot off and re greased them.

One other thing is if you want more braking performance and safety then do the ss/ext brake upgrade

Also yes the slide pins stay in the caliper

Idk how much you got the brakes for but they got a kit on rock auto for $180 that has front and rear pads & rotors and they are "pre broken in" so they should be a plug and play kit with no need to break them in yourself

 

[Mounce]

Or you can get a complete set of 4 drilled and slotted rotors and complete set (8) ceramic pads from Ebay. A few members here have them and are happy with them, the brand is brakemotive, let me know if you need a link, they're kinda hard to find.

I would say the brakes aren't too hard, just expect to be sore, there's a lot of wrenching. Only tools i used besides jack and jack-stands was a breaker bar, a 13mm and 18mm socket, and c-clamp style vice grips. If you get stuck on anything just post up here, done a front brake job on mine about two weeks ago, everything is still fresh on my mind.

 

[24v 4.2]

Make sure you don't let your calipers hang by the brake lines (this can internally damage them). I usually hook a bungie cord to the front spring and then through the hole in the caliper to hold it up.

BrakeMotive (ext) front rotors with the Ext bracket. (You must have 17" wheels to run Ext brakes up front)

 

[ComputernerdBD]

Well looks like I am going to have to send these rotors back.... In this case I might as well send the whole thing back and order a new setup for the front. They seem to have a casting defect in the cooling vanes with metal missing. Considering that it is only on one side on both rotors, I am not comfortable putting them on this car. Photo attached.

My other question about the slider pins: How do I get them out and how/where do I put the grease in safely? Thanks



EDIT: Has anyone used PowerStop rotors before? I am considering my options and the possibility of getting new rotors and keeping the AC Delco pads I have. Thanks

 

[BHAMER]

If I am looking at this correctly, the spot your talking about is the flat spots? If i recall correctly those are where the rotors were milled for balance. I'm pretty sure that is standard for this day and age. I'm sure if I am wrong somebody else will know for sure what it is for.

 

[Mooseman]

A lot have used Brakemotive and Powerstop with good results. I just recently installed Powerstop up front and so far, so good but it's too early to really judge them.

Although there is probably nothing wrong with those ACDelcos (yes, those slots are for balancing), I have had ACDelcos warp on me using their pads as well. Blank rotors are also better than drilled/slotted which are really just for show.
WHY Blank rotors are better than cross drilled and/or slotted
Cross-Drilled Rotors Myth
And there are tons of pictures of cracked drilled rotors.

Also stay away from CCC (Cheap Chinise Crap) rotors:
http://www.aa1car.com/library/raybestos_rotor_warning.pdf

 

[ComputernerdBD]

Thanks for the tips. Yes I am talking about the flat spots where metal is missing as I have never seen anything like that before and it almost looks like a bad batch as it is on both of them.

With the AC Delcos: Oh really? Would explain alot since that seems to be my problem and the brakes were brand new when I bought this car in April 2013... Warped/grooved rotors...

So great. I should stick with "normal" non-drilled rotors. Any recommendations on the brand I should be using? I am not sure about the EXT upgrade just yet unless I know for sure my wheels will fit. It is a great idea that I would like to look into though. Thanks

 

[Mooseman]

All rotors are made in China as there are no more foundries in North America. All were bought by the Chinese and shipped over there. ACDelco are made in China. As said earlier, lots of good reviews on Powerstop and Brakemotive.

 

[ComputernerdBD]

China??? That's too bad. Feel bad putting Chinese parts on an American car.

After further research, I have decided that I need better braking power but do not want to put a specialized brake kit on my truck. I would like to go the EXT/SS front rotor route. Is it as simple as swapping the rotors/brackets/pads/slider pins for parts intended for an EXT/SS? Will it just work or any other mods needed?

By the way I noticed that the rotors on my truck have almost the same flat spots in the cooling vanes, but they are alot smaller..... I stand corrected.

 

[Mooseman]

All you need are the EXT caliper brackets with slider pins and the EXT rotors. Everything else is the same, including pads.

 

[Mounce]

Doesn't it require the 17" rims?

 

[Mooseman]

Oh yeah! Forgot about that! Very important detail!

 

[Mooseman]

Oh, and yours is an 07 and there weren't any more EXT's being made then. Brakes changed design a bit in 05 or 06. The pads changed as well as the calipers so the brackets likely changed as well. Look for V8 TB's and Envoys, 06+. Having an 02 TB EXT and an 06 Saab 9-7x V8, I saw the differences. Calipers went from aluminum to cast iron for one. Pads also changed. The V8 trucks have the bigger brakes.

 

[ComputernerdBD]

So as long as I get the parts on Rockauto for an 07 Trailblazer SWB with a V8, all should be fine? It seems I have 18" rims, so no worries there. Thanks

EDIT: It looks like the part numbers on the reman calipers are different between the 07 4.2L and 5.3L, but the same on the OEM calipers on Rockauto. Did those change as well in 07? Meaning I would need new calipers? It seems the part numbers on the AC Delco pads are the same as the 4.2L and 5.3L.

 

[IllogicTC]

All rotors are made in China as there are no more foundries in North America. All were bought by the Chinese and shipped over there. ACDelco are made in China. As said earlier, lots of good reviews on Powerstop and Brakemotive.

Or American companies cheap out by sending manufacturing to China. That $600 iPhone was built for a small fraction of that by Foxconn in China. Michelin does a lot of their tires over there, which means the U.S. tire tariff is going to really jack the prices on them. We own a factory in China which does some of the extrusions for our patio door line, but all other extrusions are made locally, for whatever reason.