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Poor Braking


emiracleworker1
01-16-2010, 05:04 PM
I've read a ton of reviews on the newer Chevy trucks and the complaints about braking performance and I don't think my issue falls under that category. Personally, I used to be thrilled with the response of my brake pedal on my 06 Silverado (discs in front and drums in rear). In my quest for knowledge on this thing and the fact that I finally have to put some work into the truck, might as well cover all the bases and make for a big weekend of repairs: This truck used to have a very touchy pedal and I loved it. Now I am noticing that the pedal feels normal, but I'm having to press a lot harder to make the truck stop. It's not spongy or soft and the pedal never goes to the floor or any of the common traits associated with air in the lines. Everything feels normal short of the fact that I can't put the truck in a nose dive with a quick pop on the pedal. The issue should also not be mistaken as "I can't stop the truck quickly if I had to".

I'm on my 3rd set of front pads and 2nd set of real shoes (91K on the truck). The first 2 sets on the front were the $40 pads. Recently I replaced the discs and pads with the high dollar stuff, hoping to get longer life out of the pads and maybe help this problem disappear.... The first set of brakes done on the truck was in a similar issue. I was noticing that the braking power was fading and I needed brakes. Got the truck back from the shop and almost put myself through the windshield the first time I tapped the brakes... which leads me to believe this isn't an issue of needing brake lines or anything like that. This time I didn't get that surprising "new" brake feeling with all new parts. Could this be something as simple as mis-adjusted rear pads and do they really assist that much in braking performance? Is there something stupid like a proportioning valve that needs to be reset? Is there a special procedure to swapping brakes different from the older vehicles I am used to? Thanks in advance for any insight.

777stickman
01-16-2010, 06:04 PM
Did you have the new front rotors turned and resurfaced? New rotors and pads need a certain "easy" break-in to be effective. With only 91K on your truck and into the 3rd set of brakes it sounds as though either your diving style or Colorado terrain is dictating hard braking.

As far as the rear drums and proportioning valve. Normally the P-valve will allow 60-65% braking pressure to the front with 40-35% to the rear. This is due to the weight transfer during braking where the fronts have more down force and the rears will unload.

The rears could be an issue. Need to check for proper adjustment back there. From your post though I would suspect that you just need to break-in the fronts since you went with probably harder pads.

Hope this helps and good luck.

j cAT
01-16-2010, 06:51 PM
with rear drums the loss of braking is worn drums...the reason this is a problem at 90,ooomi is the fact that asbestos is no longer used for brake SHOES..since this is the case rapid wear of the drums is a fact...

when the drum wears the shoes no long are the same radius as the drum ...as a result the top part of the shoes is in contact with the drum only [not the complete shoe surface]....

on removal this will be very obvious..

emiracleworker1
01-17-2010, 09:18 AM
Both replies are interesting. Nothing was done with the new front rotors other than pull them out of the box and install them with the fresh pads. Is there a specific break in procedure for the brakes? Should I have them machined even though they passed the straight edge test and are new?

Regarding the 3rd set of pads with 90K on the truck... I completely agree that is excesive. Of course anybody bidding to do the brake work tells me I'm lucky to get 30K out of a set! I'm used to my 92 Chevy that's on it's 2nd set of brakes with about 200K on the truck! My little VW's or Audis hit the junk yard before they need brakes. I do work in the mountains and seems like I'm always driving downhill when I'm worried about brakes and uphill when I'm low on gas.... so I am on the brakes more than most people, just never thought I'd be going through them 3 times more than I used to.

Interesting you mention the drum being worn. I did notice after my last alignment, the guy told me I needed back brakes.... pulled it apart and only the tips of the pads were worn. Common sense tells me that having the drums turned will only make this worse... meaning should I just go ahead and throw new shoes and drums on the back before getting worrie about anything else?

j cAT
01-17-2010, 09:47 AM
I've been repairing brakes for a long time. the front rotors when rusted will need to be replaced or trimmed if not too worn.

using 120/180 sandpaper after cleaning the rotor face with minerial spirits, scratch the surface in a rotating patern to remove the shine...this will help in brake pads seating in to the surface ,,just a couple of hundred miles ...

whenever replacing pads open the bleed screw , then push back the pistons..the piston fluid is loaded with debis/moisture.

on the rear shoes when the worn shoes are not evenly worn top to bottom this means the drum is worn ,,,,,the more its worn at the top the more severe the wear is..

since you have drums in the rear brake wear will be different than a rotor vehicle...also the self adjusters need be working correctly..use of the parking brake will hopefully adjust the rear shoes ....

with my rotor brake silverado I got 90,000mi on the front OEM original pads...at 120,ooo this year I just replaced the rotors front and rear 10yrs old , rusted too badly to cut...the rear pads I get 30-40,ooomi...

brake wear is variable can't say what is normal depends on driving environment..

with rotors /caliper binding is a common issue with the poor quality of metals used by GM....these rear calipers on my vehicle are very poor quality and this complete rear brake system on my 2000 1500 silverado should have been completely replaced with better design/metals.

the only reason I got better results than most was because of removing and cleaning / lubing the rear brakes every 10-13,ooomi..

cramer_77
01-17-2010, 11:58 AM
i have ran into a few issues like this at my work, i see you said you bought the higher dollar pads. The higher dollar pads can have more ceramic to them, which in turn will cause that feeling to the pedal and it takes more pedal effort to actually stop the truck. Have you noticed your braking distance increase? As far as a break in procedure for those, i've never been told of a procedure to follow, just a few easy stops from about 30 with normal effort then a few harder stops from about 50-55 with a little harder push on the pedal. Actually 30k on a set of brakes sounds about right, most cars i work on need brakes anywhere from 30k to 40k, and seeing as how you said you drive downhill more often then thats gonna wear them out quicker. I can't really help you with the rear drum issue im not that good with drum brakes.

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