Hi!
Until it sounds like a brake drum?
(Seriously...the local high school band department has one that's used as a musical instrument in the percussion section...)
William The Guesser (out of smarty remarks at the moment)
Hmm, interesting observation.
Brian
I have read your argument with great interest. While I feel that you have raised valid points as to the possible weaknesses inherent in the rear disc brake system, I still believe that GM has used the switch from rear disc brakes to rear drum brakes as a way to reduce cost in its low-end trucks. Notice that this change only affects the Silverado 1500. The Silverado 1500HDs, 2500HDs, 3500s, Yukons, Suburbans, Avalanches and TrailBlazers still have the more expensive rear disc brakes.
My argument is that GM should have addressed the two problems that you mentioned above (parking brake wear out AND rusted pins on the on the rear disc brake sliding calipers) and made a better 4-wheel disc brake system. Even the enhanced rear drum brakes on the 2005 Silverados will not be able to dissipate heat and water nearly as well as the previous year's disc brakes.
The problem that I consistently had with the rear drum brakes on my 1990 Scottsdale was out of round brake drums. Soon after a rear brake job, complete with either turned drums or new drums, the rear drums would get out of round. I believe that this was caused by the park brake system pressing hot shoes on hot drums. This is not an issue with rear disc brakes, because the park brake has its own independent brake drum and shoe assembly. If people want to drive around with the park brake on or jamb down on the park brake before the vehicle is completely stopped, they can't blame GM for the resulting problems. As it is, the park brake warning system consists of a bright instrument panel light, combined with a loud chime, if you try to drive off with the park brake engaged.
If the answer to GM's brake problems lies in a beefed up front disc brake system combined with a beefed up rear drum brake system, why didn't they put this "improved" heavy duty system on the larger trucks and SUVs that REALLY need the extra stopping power? It seems to me that cost is the reason that rear drum brakes were not put on the 2005 Silverado 1500HDs, 2500HDs, Yukons, Suburbans, Avalanches and TrailBlazer for 2005.
A small cost reduction in vehicles which have starting prices of $29,000 and up would be a drop in the bucket. But on entry-level 2005 1500 model Silverado trucks with a standard price of $18,735, the difference would be far more noticeable. The 2005 Silverado 1500s already cost $395 (2%) more than their 2004 counterparts. If GM saved $200 per vehicle by downgrading the brakes, they would have avoided increasing the price of their trucks by another 1%. A price increase of $395 seems a lot less than a price increase of $595.
Here are some excerpts from an article which seems to have originated in the advertising department of GM:
"Complaints about the brake characteristics of the 2004 Chevrolet Silverado pickup, above, and GMC Sierra, prompted changes in the design to improve the braking performance of the 2005 Silverado and Sierra."
"Bosch, GM bolster truck brakes; Joint project reduces pedal pressure, distance for stopping of 2005 Sierra and Chevrolet Silverado."
"Brake upgrades in the Silverado and Sierra include a new master cylinder, above, that helps reduce pedal travel, larger front rotors and larger rear brake drums."
"With the new brakes, the amount of time needed to stop has been reduced by two seconds and stopping distance has been cut by 85 feet, using just the front brakes." Unfortunately, this is all the article has to say on the subject of time and distance. The figures are meaningless without first telling how fast the vehicle was traveling and what other vehicle -- or vehicles -- were used in the comparison. And what happens when the new, larger rear drum brakes get wet? Do they still stop faster than disc brakes?
"Working with two or three lower-tier suppliers, Bosch improved the stiffness in the front brake calipers to reduce pedal travel - the distance a driver must depress the pedal before braking begins - changed boosters and redistributed power between the front and rear brakes."
" "We did more with the front and a little less with the rear for overall better brake distribution and balance," Brennan said."
"Despite the improvements, the system will not cost more to install because the federal government has dropped requirements for certain brake control components, said Terry Woychowski, GM's chief engineer for full-size trucks."
According to this:
And maybe 4WD as well, if this review is correct:
"Quadrasteer is no longer available on 2WD models, standard wheel sizes have been bumped up to 17 inches and, on extended and crew cab models, a power sunroof that includes HomeLink and a deluxe overhead console in now optional. GMC takes a step backward this year with the return of rear drum brakes, as opposed to last year's four-wheel disc setup. Big changes for the Denali this year -- Quadrasteer is no longer available, and the Denali is now a crew cab model only."
PUTNAM CHEVROLET-CADILLAC-HUMMER, INC.
198 CALIFORNIA DR BURLINGAME, CA 94010-4323 2005 Silverado 1500 Regular Cab Standard Box 2WDSTANDARD EQUIPMENT Items Featured Below are included at NO EXTRA CHARGE in the Standard Vehicle Price Shown at Right
*** SAFETY & SECURITY *** . 4-WHEEL ABS W/DYNAMIC REAR PROPORTIONING . DISC/DRUM BRAKES *** *** ***ANDERSON CHEVROLET
300 EL CAMINO REAL MENLO PARK, CA 94025-52392005 Silverado 1500HD Crew Cab Standard Box 2WD
STANDARD EQUIPMENT Items Featured Below are included at NO EXTRA CHARGE in the Standard Vehicle Price Shown at Right
*** SAFETY & SECURITY *** . 4-WHEEL ABS W/ DYNAMIC REAR PROPORTIONING . 4-WHEEL DISC BRAKES*** *** ***
STEWART CHEVROLET CADILLAC OLDSMOBILE
780 SERRAMONTE BLVD COLMA, CA 94014-32842005 Silverado 2500HD Regular Cab Long Box 2WD
STANDARD EQUIPMENT Items Featured Below are included at NO EXTRA CHARGE in the Standard Vehicle Price Shown at Right
*** SAFETY & SECURITY *** . 4-WHEEL ABS W/DYNAMIC REAR PROPORTIONING . 4-WHEEL DISC BRAKES*** *** ***
GOLD RUSH CHEVROLET INC.
570 GRASS VALLEY HWY AUBURN, CA 95603-38322005 Silverado 3500 Extended Cab Long Box 2WD
STANDARD EQUIPMENT Items Featured Below are included at NO EXTRA CHARGE in the Standard Vehicle Price Shown at Right
*** SAFETY & SECURITY *** . 4-WHEEL ABS W/DYNAMIC REAR PROPORTIONING . 4-WHEEL DISC BRAKES*** *** ***
To view Chevrolet window stickers, go here:
The other thing I noticed while wondering around on the "Build your truck" GMC site was that if you get the quadrasteer option, it includes cab running lites. Why??
I forgot my camera (brain does not work well in the morning), but I did do some diggin around at work. It appears that GM's info is a bit confusing. I even asked some of the new truck sales guys, and they were scrambling and quite interested in finding out what the scoop really is. If you look in the Silverado specs sheets, it appears that a "base" 1500 only comes with drums brakes on the rear, but the two trim levels above the "base"...."LS"...and "LT" come with the rear disc brakes. But then a note says that you can get rear disc brakes on the the "1500HD", the SS model, any trucks with rear wheel steering, and the "hybrids". From what I can glean...it looks like the base "work" truck is what comes only with drums brakes...but you can still get rear disc brakes on a 1500 series truck. We seem to sell mostly HD trucks....(at least that's all I saw in the shop today) and of course they all come with rear disc brakes.
I'll keep my eye open and see if I can figure out what truck comes with what.
Ian
Thanks for doing the research. It really comes as no surprise to me that the sales people didn't know too much about the brake situation with the
2005 trucks. I'm glad that they were interested enough to find out.There will probably be a lot of controversy about the brakes, because the "DISC/DRUM BRAKES" line appears prominently on the sticker. Maybe GM should remove all reference to the brakes from the window sticker. People will naturally assume that GM puts industry-standard rear disc brakes on its 1500 trucks. (Little do they know!)
Here is the most expensive ($32,965.00) LT 1500 that I could find. This truck is typical of all LT and LS trucks that I have checked. All of them had lots and lots of options, but NONE of them added rear disc brakes to the list of options. HD TRAILERING EQUIPMENT, HEAVY DUTY SUSPENSION and LOCKING DIFFERENTIAL-REAR AXLE, of course. But no rear disc brakes.
SINGH CHEVROLET
8200 AUTO DR RIVERSIDE, CA 92504-4106 Phone: (951) 688-8111 Fax: (951) 687-77032005 Silverado 1500 Extended Cab Standard Box 2WD VORTEC 5300 V8 SFI GAS ENGINE
4-SPD AUTOMATIC TRANSMISSION DARK GRAY METALLIC MEDIUM GRAY VIN: 1GCEC19T85Z149422MANUFACTURER'S SUGGESTED RETAIL PRICE
STANDARD VEHICLE PRICE $ 32,965.00
Options installed by Manufacturer LIGHT DUTY POWER PACKAGE: VORTEC 5300 V8 SFI GAS ENGINE LOCKING DIFFERENTIAL-REAR AXLE HD TRAILERING EQUIPMENT $ 625.00 SAFE & SOUND PACKAGE: XM SATELLITE RADIO - OVER 130 CHNLS OF DIGITAL ENTERTAINMENT SERVICE FEE EXTRA.1ST 3MOS.INC $ 325.00 TOTAL POWER PACK SAVINGS $ -2,000.00 LT DECOR INCLUDES: FULL FEATURE BUCKET SEATING OSRV MIRRORS W/ DRIVER SIDE AUTO DIMMING, PWR FOLD & ADJ. HEAT, TILT & TURN SIGNAL REAR WINDOW DEFOGGER DEEP TINT GLASS FRONT FOG LAMPS AM/FM STEREO W/ 6-DISC CD CHANGER & BOSE SPEAKER SYSTEM ALUMINUM WHEELS POWER LOCKS & WINDOWS REMOTE KEYLESS ENTRY WITH CONTENT THEFT ALARM ISRV MIRROR W/COMPASS & TEMP LEATHER WRAPPED STEERING WHL BODY SIDE MOLDINGS ONSTAR SYSTEM INCLUDES 1 YR SAFE & SOUND REDUNDANT RADIO CONTROLS FLOOR COVERING AUTOMATIC A/C GRILLE, COLOR-KEYED SURROUND GVW RATING - 6,200 LB HEAVY DUTY SUSPENSION REAR AXLE - 3.73 RATIO $ 100.00 TOTAL OPTIONS $-950.00 TOTAL VEHICLE & OPTIONS $32,015.00 DESTINATION CHARGE $850.00
TOTAL VEHICLE PRICE* $ 32,865.00
STANDARD EQUIPMENT Items Featured Below are included at NO EXTRA CHARGE in the Standard Vehicle Price Shown at Right
*** SAFETY & SECURITY *** . 4-WHEEL ABS W/DYNAMIC REAR PROPORTIONING . DISC/DRUM BRAKESMotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.