Drum brakes on rear?

Does anyone know why Chevy would go back to drum brakes on the 1/2 ton 4X4? 6400 lb GVWR and drum brakes, it makes absolutely no sense to me. Are they just trying to kill off their buyers?
And the w/s wiper blades will no longer stay up so you can clean the windshield.....what's up with that?
Chuck
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Chuck wrote:

Because drum brakes don't have the fade or parking problems like disc, they are better for carrying loads, discs are fine for sports cars but not work trucks.
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Uhhh...the 1500HD, 2500 and 3500 have rear disc. Not trying to start a flame here but other than Chevy trying to cut ten dollars off of the cost of building them it makes no sense to me.
It just seems to me they keep cutting the extras and the other manufactures keep adding them.
I've driven Chevy's for almost fifty years but my next one probably won't have a bow tie. Sad.
Oh well.
Chuck
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With a few exceptions class 8 trucks (semi's) wear drums all the way around. Although the braking mechanism is diffrent the pads and drums are the same, except size, as a pickup. Disks are availabe and were popular a few years back but since have faded away. But I'd have to agree with a previous post about weight bias, fact is unless you have weight on the rear to hold it down a good set of disks on the rear would be working the ABS modulator to death. With cars the weight bias is alot diffrent, closer to 60/40 with some near 50/50. Disks would be more logical and easier to control in that
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David Johnson wrote:

Personally, I think that the idea that a light duty truck with rear disc brakes "works the ABS modulator to death" is a bunch of baloney! I've driven this trucks since they came out with rear disc brakes and they do not exhibit any more ABS modulation from the rear brakes then any other vehicle. In fact, the older trucks with drum brakes had more problems with premature lockup of the drum brakes in the rear then the new trucks do. I test drive these vehicles every day, plus work on them....and believe me, if this was a legitimate concern, I'd hear about it from the customers, and/or would see product bulletins from GM about it.
Ian
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Nope... Drum brakes are *worse* about fading... As far as carrying loads, I've never heard of the brakes themselves carrying the load or affecting the vehicles ability to do so.
Disc brakes shed water and dirt much easier than drums do. They also weigh a helluva lot less.
In terms of having a parking brake, there are calipers available for rear disc brakes that provide a parking brake mechanism. For instance, folks that convert their rear drums to discs on GM 14-bolt FF axles can use 1976-1978 Cadillac Eldorado calipers that have parking brake provisions.
~jp
Eugene Nine wrote:

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Jon R. Pickens wrote:

Not sure where you come up with the assertion that Disc brakes weigh less then a comparable drum brake setup. I can tell you from personal experience that this is not true with the particular trucks we are talking about. The disc brake rotor is heavier then the drum and the extra park brake shoe mechanism and mounting hardware easily are heavier then a couple of brake shoes.

The GM rear disc brakes on the trucks have been a lot of trouble since their inception. Especially if the truck goes through a lot of water, mud, dirt....etc. The park brake mechanism is marginal at best, and due to a poor design, wears out even when you never use the park brake. Now, this was addressed in 2003, but I think that for the average guy using a light duty truck, the drum brakes on the rear will turn out to be cost effective and safe over the long run.
Ian
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shiden_kai wrote:

This is just what I've always heard and read. I wasn't talking about any truck in particular, but rather the 14-bolt axles when using a disc brake conversion. Supposedly ditching the drums and installing discs is a weight-saver on that particular axle, or so I've always heard...

Again, I was talking about the 14 bolt conversion, not stock disc brake parts on a 1/2 ton truck. I can't comment one way or another on their performance or longevity vs. stock parts either. Does the parking brake mechanism in those Caddie calipers wear out as often? I'm curious, as I still plan to replace the once again failed rear 10-bolt in my K5 with a 14 bolt, and had planned on doing the disc brake conversion.
Thanks,
~jp
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Jon R. Pickens wrote:

If you are DIY'er who is able to keep the park brake system on those old calipers working, then yes, go for it. They had plenty of problems with those rear disc calipers that had the park brake mechanism integral with the caliper. The Fiero had them, the Caddies had them, the F-bodies (firebird, camaro) used them, and they all were problematic. Unless you knew how to properly adjust them (they are supposedly automatic adjusting, but in real life that did not happen).
The only GM rear disc brake calipers with integral park brake mechanism's in the caliper that worked properly were the late model W-body cars. No problems with them. These calipers are also used on late model Caddies with some modifications. I did a four wheel brake job on one on Friday.....absolutely no problems with the rear park brake mechanism. Simply screw the piston back in and away you go.
Ian
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Hmm... Well I see that the W-bodies are fairly small compared to a big Chevy Truck! Would those calipers fit the big rotors that one would want to run on a lifted truck with 37-38" tires?
~jp
shiden_kai wrote:

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Jon R. Pickens wrote:

No, I don't I could recommend that.
Ian
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shiden_kai wrote:

Corrected.
Ian
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True,the new GM trucks 2005-2006 have rear drums, no?

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Shep wrote:

Yes.
Ian
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Greetings,
Ok, I'm in full agreement with the thing about the windshield wipers not being able to fold up to clean under them. In fact, on my '04 I can't even fit a normal sized squeegee from a gas station under the blade on the passenger's side wiper without rubbing the rubber blade. Not the best idea on GM's part...
However, when it comes to drums instead of disc brakes, here's some things I've picked up over the past few years that folks may or may not agree with.
First, while discs are apparently superior to drums, the rear discs on these trucks picked up a lot of dirt that accelerated wear and other problems. The 1500 series trucks were expected to be purchased more for family transportation that for heavy towing so the drums made sense from a wear/repair perspective. The discs were kept on the larger capacity trucks because they were preferred for trucks that did more towing and hauling that typical car work.
Second, pick-ups have a natural weight distribution bias towards the front of the vehicle (around an 80:20 split front to rear). The brakes on the light end (in our case the rear) did much less work than the ones at the heavy end because less weight over the axle means less traction for the tires. As it turns out, disc brakes were too powerful for trucks that did not typically haul or tow (remember that the vast majority of half-ton trucks were purchased as transportation and not for hauling loads) and with disc brakes on the light rear end the number of activations of the ABS because the rear wheels lost traction under moderate to hard braking were tremendous. Using the less efficient drums on the light rear end of trucks that typically don't carry loads reduced the effectiveness of the rear brakes and lowered the number of inadvertent ABS activations significantly since now the rear wheels were less prone to locking up from loss of traction due to hard braking.
In that same vane, the rear discs were kept on the higher capacity trucks (again) because these trucks were expected to haul loads more often than the 1500's (increasing weight over the rear axle which increases rear wheel traction, requiring the brakes to be more effective, and therefore having a reduced number of ABS activations anyway without having the need to use less efficient brakes).
It may sound like so much hot air, but it all does make some sense in a round-about sort of way, but take it for what it's worth.
Cheers - Jonathan

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