They were in some way upgraded to compensate for the rear drums.

Id like to upgrade, if its worthwile.

 

i read in CHP that the reason chev went with rear drums was they changed the design of the rear housing, and didnt design a rear disc setup for that rear, but this was on the 2 wheel SS truck for 06. They stated that the 4 wheel discs stopped better.

 

Yes, that statement holds truth. I will tell you myself that the new drum brake design is of poor design. The new drums they use are too thin to start with. They tend to warp fairly quickly.
If you look at the way the springs are holding the shoes, you will also see that the shoes can actually shift from one side or the other. They didn't use the retainer spring that usually each shoe would have to hold it in place.
A few mechanics have told me that the design was used on some of GM's cars in the past. He said they had nothing but problems due to the design.
I believe this, because I've been having nothing but problems with the drum brakes ever since 10,000mi.
I would switch to Baer Brakes disc kit, but I don't want to big 14" rotors out back.
Then I couldn't find a slick that would fit on a rim that would clear the disc brakes!
I'm very surprised to find that no one else with the drum brakes don't have problems with them warping.
I have had 2 different rental Silverados. Each had about 20,000-25,000mi.
One was a 05' and the other was an 06'. Both were 1500, 5.3L, 4-door Silverados with rear drum brakes.
Both trucks did the same thing that my truck does. That goes to tell me that you guys that do have 05+ Silverados with drum brakes, just are not paying attention to it. I can't see how you can ignore it though. It's not slight either. The warpping is very agressive and apparent.
If your truck doesn't come to a smooth stop, then it's the rear drums!
Mine lunges at every stop. You can feel it grabbing the drum in multiple high and low spots.
When it's cold (like in the morning) it is not so bad. But after 10 minutes of braking, it gets bad.
I CANT STAND IT!!
The 05 & up 2WD & AWD SS's came with the same rear brake set-up as my 05' VHO's.

Jim

 

off topic alittle but what is up with GM's disc breaks on their FWD cars? my wifes 04 impala LS has 23,000 miles and im getting ready to put it's 3RD set of rotors on the front!!!! Nothing but warpage! WTF, this is bull, i cant wait to get rid of it for a tahoe/TBSS!

 

my wifes 05 truck does not have any brake problems.........Yet, her truck has about 7,000 miles on it.
I really don't like the idea of drum brakes when the disc worked well IMO.

 

My truck has the same issue. It's worse sometimes more than others, but definitely annoying.

Short of swapping out rear axles with an earlier model, I guess I'm stuck with it.

 

I have noticed a bit of the grabbing or vibration on my 06 Z71 when stopping. Its a little annoying, but not all that bad, don't know if the different suspension setup of the Z71 has something to do with it, but like I said, its not terribly noticable.

I'm not too worried about it though, my girlfriend is fixing to start driving the Z71 and I'm going to take her 04 Sierra. She doesn't notice stuff like that much, so she probably will never even notice it. lol.

 

So I see that this issue is starting to show it's ugly face. It will start around 12,000mi. It will progress with more mileage from there.
GM used too thin of metal on the drums. They also don't have any heat sink fins around the outside of the drum. Therefore it will retain heat for a longer time and then of course it will warp. When this constantly happens the drum it self will fatigue and just get weaker over time.
The thing that I don't get is, they placed new drums on mine and it warped in two weeks. Then it just got worse. The dealer then returned them and would only last one day without it warping. The dealer has serviced my rear drums 6 times and has yet fixed the problem. They even replaced the brake booster.
GM will never fess up to this problem in my opinion. They couldn't afford to recall all the 05 & 06 trucks for a rear drum fix.
I might end up just placing Baer's disc brake conversion kit on.

Jim

 

Ok, we're all in agreement that the drum brakes suck.

Can we get back to the orginal question - Does anyone know if the larger FRONT brakes from a 05 and up truck can be swapped over to a pre-05 truck?

It would be a nice budget upgrade for lots of people here if we can figure this one out.

 

Since the part numbers for aftermarket spindles are the same for all 99-06 trucks, I would imagine that it would be a pretty easy swap. Not sure if you would run into any problems with the ABS, master cylinder or proportioning valve, but that probably wouldn't be too terribly difficult to overcome.