GM Truck Self Adjusting Parking Brake

Sorry if the cross posting offends anyone - but I wanted the same info to go out to both groups. I've seen this general topic discussed in both groups
in the past.
I have an 02 Chevy Suburban half ton 4wd. It's had to go back to the dealer twice for parking brake adjustment - the PB would go to the floor and not hold. Both times it was adjusted w/o charge. They had to adjust the brakes themselves, not the cable. Neither time did they give me any advice. I have an acquaintance who is a GM mechanic at a different dealer and I asked him if these brakes are a problem he sees a lot. He gave me advice that my dealer should have given to me the first time I brought it in.
He told me that they are self adjusting in that they adjust to wear in the brake pads - but only if you use them regularly. This may be a *DOH* to some people, but it wasn't for me and I was a little frustrated that my dealer's mechanic hadn't advised me as such. In fact, last winter, the PB were binding and the dealer actually told me not to use them in the winter because they would tend to freeze up and bind.
My acquaintance told me that all you have to do is to set the brakes every week or so, but if you don't use them regularly, the pads will wear, the self adjustment won't work and the brakes won't hold when you need them. I'll get back in the habit of just using them routinely for parking and, as for use in the winter, I'll just set them in the garage at night. He also told me that the PB pedal "normally" goes down to the floor to set it a feature that I dislike, but will live with.
FYI, HTH, etc.
DJ
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"DJ" wrote

I don't think your friend is very familiar with these brakes. They do not self adjust at the park brake shoes, nor is the cable adjustment used as an "adjustment". It's strictly there so that you can back it off if necessary when removing the rear rotors. The park brake pedal assembly itself has some self adjusting capabilities, but from what I've seen and experienced, it can't self adjust enough when the park brake shoes are worn to be effective.
There is also a bulletin out for these park brake shoes. There is a changeup retaining clip that is supposed to reduce the brake shoes wearing when they are not in use. You might want to have that addressed by your dealership. The bulletin is:
Scraping Noise From Rear of Vehicle (Replace Parking Brake Shoe Kit and Clean Drum in Hat Rotor) #02-05-26-002A - (01/28/2003)
Ignore the "scraping" noise part.....that is a problem, but the real problem is premature wear of the rear park brake shoes. The scraping noise is just an indication that the shoes are contacting the rotor when they shouldn't be.
Ian
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Sorry if I was unclear, but I can't understand why you said my acquaintance (actually, he's not a friend - I don't know him that well except as a mechanic) is unfamiliar with the brakes. I didn't say he recommended any cable adjustment, nor did I say anyone had ever told me the cable could be adjusted to correct the problem I was experiencing. He also didn't tell me where exactly in the system they self adjusted, just that they wouldn't do so unless used regularly. Is this not the case?
It's strictly there

I didn't mention anything about the park brake shoes being too worn to be effective (at least I don't think this was the case because they were able to adjust them and make them work). What I said (or meant to say, sorry if it was unclear) was that as the brakes wear, the system adjusts to that (I have no idea what part of the system), but won't do so unless used regularly. Are you saying this is incorrect? What does the park brake pedal assembly self adjust to? Is it not true that the self adjusting feature (wherever it lies) won't self adjust unless used regularly?

Thanks. I haven't experienced the scraping noise, however, I'll refer them to this service bulletin next time I'm in and I appreciate the pointer.
Thanks for your comments, but again, I'm wondering if what he told me is untrue - that I need to use the parking brakes regularly or else they won't self adjust and will eventually not hold.
DJ
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"George" wrote

You are right, under normal circumstances, the park brake shoe shouldn't wear. But this is what this bulletin is about....the brake shoe retainer design allows the shoe to move into the drum section of the rotor when it "shouldn't". You hear a scraping noise, and you get premature wear of the shoes.
Ian
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Thanks - its understandable now. .

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"DJ" wrote

There isn't any truth to that...at least with these particular park brakes. The pedal is self adjusting and will self adjust as soon as you hit the pedal. It wouldn't make any difference whether you used the brake a lot or a little.
Anyway, your best bet is to get the updated retainers and shoes installed.
Ian
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On Mon, 14 Jul 2003 23:16:20 GMT, "shiden_kai"

Do you have all of the dope on these? My '01 is going in for the last of the update items (I think) and would like to include this. My fourth time for the nickel plated slip yoke... "would you like to give me back $33,500 for this truck? Ian you work at a Dealer, why the cold shoulder?
Have a great one!
Bush
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"Bush" wrote

I'm not sure that I understand your last sentence? More clarity please.
If you want to get new park brake shoes, complain about a scraping noise from the rear brake area at slow speeds, and complain that your park brake doesn't hold as well as you think it should. If they are on the ball, they will go to that bulletin and see what the fix is.
I took a couple of pics of one I was working on today, but can't get the pics uploaded. When I do, you can see the difference between the retainers. Basically, the new retainer allows the brake shoe to float more, so that it won't stick in one position and wear itself out against the drum section.
Ian
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The rear brakes will wear with normal braking use, independent of parking brake use. The brake system automatically proportions braking pressure between the front and rear brakes to optimize your stopping power. Typically, most systems run something like 80% front and 20% rear, and some systems are even adjustable.
The thing that makes this interesting is that several of the rear brake auto-adjusters( speaking of drum brakes here) only work effectively after setting the parking brake and then attempting to roll backwards on the brake-I believe this is actually called out in some of the owner's manuals. As pointed out on some of the earlier threads, failure to use and keep the rear brake adjusted makes it nearly impossible to do so without dis-assembling or manually adjusting--i.e.. crawling under the vehicle and using a brake tool in the slot.
--
MC

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