1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Resurfacing rotors, drums (esp OE)

Discussion in 'Tech Discussion' started by AuroraGirl, Oct 20, 2020.

  1. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

    Age:
    22
    Posts:
    3,440
    Likes Received:
    1,920
    Joined:
    Sep 8, 2019
    Location:
    Northern Wisconsin
    First Name:
    Taylor
    Truck Year:
    1978, 1980
    Truck Model:
    K10, K25
    Engine Size:
    400(?), 350
    So its actually about my car(story below) but It could go for the drums on my square when i fix the rear brakes. Hell, it could apply to the front rotor(not the spindle lol, that would need to come off). My f150 has rear drum resurface coming up but thats because of low mileahe and i know they are wearing OK, and everyone online says that specific one is BAD aftermarket metal wise. and motorcraft(a joke) wants 150+ for each drum.

    Are GM replacement drums and rotors that bad or are AC Delco just generally worth keeping for the OE quality?

    My rear wheel had a separation of caliper brackets from a shop that doesnt know how to tighten bolts. Back in jan or feb i fixed it with generic part store brand rotor and pads. I JUST did the brakes the previous spring with NICE ac delco coated rotors and their quality pads. The one side had at least 10k miles on it since the brakes were new both sides. I cant reuse the one rotor, it has 3 DEEP gouges in it where the pads and bracket rode the rotor. But could I buy a new rotor, resurface the "old" one to spec with the new one?(assuming all is good spec wise) is it worth it? its like a 40 dollar rotor.
    I also have the original rotors, well, 6 actually(3 sets of 2 from cars that share the same rotor) and most are not damaged just rusty and old. But they have been indoors and stacked. Assuming specs are good, would resurfacing these be the best idea?
     
  2. Doppleganger

    Doppleganger Supporting Member Supporting Member

    Posts:
    2,217
    Likes Received:
    5,183
    Joined:
    May 24, 2019
    Location:
    OH-MI: Just like it sounds
    First Name:
    Chris
    Truck Year:
    1985
    Truck Model:
    K20
    Engine Size:
    5.7
    Local NAPA shop told me to try and resurface my original drums as they were much meatier than the new Delco's clearly stamped 'CHINA' (as is with about everything else Delco makes now).

    I wasn't aware you could turn one of these. Its been so long since I owned a rotor that wasn't a bare minimum thickness composite material (and disposable) it'd be great to know.
     
  3. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

    Age:
    22
    Posts:
    3,440
    Likes Received:
    1,920
    Joined:
    Sep 8, 2019
    Location:
    Northern Wisconsin
    First Name:
    Taylor
    Truck Year:
    1978, 1980
    Truck Model:
    K10, K25
    Engine Size:
    400(?), 350
    the rear rotor has a fortunate part where it barely is used relative to the front AND they stay cool, AND my vehicles have most of their life ownership by old farts, so the rear rotors are all relatively untouched. Front rotors.. eh.. i might have a set and a half useable on condition alone, pending checking for specification to be sure. The manaul states i have a good amount of variance of OE thickness to replacement but of course, how much was lost with time?
     
  4. eskimomann209

    eskimomann209 Supporting Member Supporting Member

    Posts:
    1,494
    Likes Received:
    1,506
    Joined:
    Jan 9, 2019
    Location:
    Modesto
    First Name:
    Marcus
    Truck Year:
    1973
    Truck Model:
    C10
    Engine Size:
    5.3
    I think the new drums on my 73 12 bolt. Measures 11” and the max diameter was 11.09
    Lead me to believe they were throw aways. The one I pulled off had the same specs.
    It was already beyond the 11.09 when I pulled it.
    I’m pretty sure it was 11.09 but regardless I know I have the range correct. It was only .09 off the original diameter.
     
  5. Grit dog

    Grit dog Full Access Member

    Posts:
    881
    Likes Received:
    886
    Joined:
    May 18, 2020
    Location:
    Washington
    First Name:
    Todd
    Truck Year:
    1986
    Truck Model:
    K20
    Engine Size:
    454
    No need to resurface a rotor unless you’re taking build up or a warp out of it.
    And 1 side doesn’t need to be surfaced to “match” the other side. They’re independent and if they run true, resurfacing is not necessary.
     
    dvdswan and Octane like this.
  6. Grit dog

    Grit dog Full Access Member

    Posts:
    881
    Likes Received:
    886
    Joined:
    May 18, 2020
    Location:
    Washington
    First Name:
    Todd
    Truck Year:
    1986
    Truck Model:
    K20
    Engine Size:
    454
    Can’t speak to the 7 different questions about 5 different things on 3 different vehicles though.
     
    80BrownK10, Vbb199 and Doppleganger like this.
  7. Poppy 87

    Poppy 87 Supporting Member Supporting Member

    Age:
    56
    Posts:
    763
    Likes Received:
    1,212
    Joined:
    Oct 19, 2019
    Location:
    Bloomingdale GA
    First Name:
    John
    Truck Year:
    1987
    Truck Model:
    R10 Silverado
    Engine Size:
    305
    Before purchasing the 40 dollar rotor, invest in a micrometer to measure the 6 rotors you currently have. Machine any within limits and drive on! Good luck
     
    WFO and AuroraGirl like this.
  8. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

    Age:
    22
    Posts:
    3,440
    Likes Received:
    1,920
    Joined:
    Sep 8, 2019
    Location:
    Northern Wisconsin
    First Name:
    Taylor
    Truck Year:
    1978, 1980
    Truck Model:
    K10, K25
    Engine Size:
    400(?), 350
    Its simple
    OE Rotors exist, source unimportant
    I have the need for 1 new rotor, it wont then therefore match my current one.
    Buy new just like current, machine both equal?
    Find two old ones in spec, machine?
    Buy 2 new?

    edit: I see you posted an answer above that, disregard.
    BUT, i would machine because new pads to old rotors, i would like to machine that to a nice surface. Also, this is only if any of them are in spec yet.
    And I said same machine to only for purpose of wear and keeping it relatively equal for replacing down the road
    i could just see issues with run out or something if you apply brakes and one, for example, has to travel twice the distance the other. Maybe not on the back but on the front, eh.they behave a little different when that far on their slide
     
  9. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

    Age:
    22
    Posts:
    3,440
    Likes Received:
    1,920
    Joined:
    Sep 8, 2019
    Location:
    Northern Wisconsin
    First Name:
    Taylor
    Truck Year:
    1978, 1980
    Truck Model:
    K10, K25
    Engine Size:
    400(?), 350
    I should look in my fine instruments tackle box.. I bought a tackle box on my gpas request and put all of his protractors, thread gauges, rulers, etc. even a slide rule. most were aluminum or stainless, 1960s or older. I bet there is a micrometer somewhere. Now time to google what one may look like
     
    Poppy 87 likes this.
  10. Grit dog

    Grit dog Full Access Member

    Posts:
    881
    Likes Received:
    886
    Joined:
    May 18, 2020
    Location:
    Washington
    First Name:
    Todd
    Truck Year:
    1986
    Truck Model:
    K20
    Engine Size:
    454
    No, that's what I'm saying. There is NO need to try and make one rotor thinner so that it matches the thickness of the opposite one. Pads don't travel a "greater distance" they are just a little closer together if the rotor is thinner.
    Also zero need or benefit to machine a good rotor that runs out smooth. Even with new pads. Some high end pads have a break in compound (sandpaper basically) on them. Same thing can be accomplished by just scuffing the rotor surface with emery cloth or sandpaper. Scuff it up to get a little more bite when bedding in your brakes. And yes bedding brakes does make them work better.

    Think about it. After you use a new rotor for a couple days, it's just as smooth and shiny as it was before you spent the money cutting it.

    Let it sink in. I know you are trying to be cost conscious and I've been being cost conscious for a long time. Even my sarcastic comments are in an attempt to get you to learn that sometimes you spend dollars tripping over dimes. We all learn it either by experience (which usually costs more) or teaching.

    If you don't have a mic to check thickness, generally if there is a significant "lip" around the edge they are generally worn close to or past their recommended minimum thickness.
     
    Last edited: Oct 20, 2020
    ali_c20 and Octane like this.
  11. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

    Age:
    22
    Posts:
    3,440
    Likes Received:
    1,920
    Joined:
    Sep 8, 2019
    Location:
    Northern Wisconsin
    First Name:
    Taylor
    Truck Year:
    1978, 1980
    Truck Model:
    K10, K25
    Engine Size:
    400(?), 350
    I would say turn them because of corrosion as they have been sitting in a pile, have minor grooves, to ensure a flat plane, and to clear that top layer of oil, grease, dirt, etc that is definitely pushed into it by now. this pile is 1-5 years old since they been on car and have been exposed to dust, moving shit, things sat on them. etc. and what i was saying was more for pedal height but i forgot that i an use my tech 2 to adjust the EBSTCM to correct pedal height with pads set on the rotors
     
  12. Doppleganger

    Doppleganger Supporting Member Supporting Member

    Posts:
    2,217
    Likes Received:
    5,183
    Joined:
    May 24, 2019
    Location:
    OH-MI: Just like it sounds
    First Name:
    Chris
    Truck Year:
    1985
    Truck Model:
    K20
    Engine Size:
    5.7
    Can find these stupid cheap on feebay as much of the machining trade is down from years ago. This is a new set of Starretts my friend was trying to sell and couldn't give them away.

    DSCF0022.JPG

    I have a set of this style - dial calipers (also Starretts)...use them on just about everything. Great for a quick check. They're invaluable IMO.

    4KU74_AS02.jpg
     
    80BrownK10 likes this.
  13. Grit dog

    Grit dog Full Access Member

    Posts:
    881
    Likes Received:
    886
    Joined:
    May 18, 2020
    Location:
    Washington
    First Name:
    Todd
    Truck Year:
    1986
    Truck Model:
    K20
    Engine Size:
    454
    Want or need to take out surface irregularities or they're warped, yes have them turned. I did not refute that. The rest of the reasons are not reason to turn them. However, you are dead set on having them turned. I would presume that since that is newsworthy to you and you said......
    "Buy new just like current, machine both equal?
    Find two old ones in spec, machine?
    Buy 2 new?"

    .... that you were somehow asking for advice, when apparently the 3 separate "?'s" in your post were just you talking to yourself publicly and not seeking advice (which I generally seek when I don't know something, or in an attempt to save time or money). And those reasons, to make them "equal" are not a reason to spend that time and money.

    Also Brake Cleaner removes "that top layer of oil, grease, dirt, etc that is definitely pushed into it by now exposed to dust, moving shit" quite easily.

    You think I don't like you for some reason, which is false. I know you make $17/hr and judging by your other posts that literally explain your whole life, my presumption is that you want to be frugal with your expenses. I also know that the rotors and the vehicle they are going on will not be affected appreciably by a used rotor that isn't "turned" unless it needs to be. So I've spent considerable time trying to help you understand the things you profess that you don't understand....again, hence the question marks in your posts.
    I'm from N WI. More N WI than where you live and I understand how hard it is to make a buck up there.
    But you appear to be the person who asks for advice, then if it's not in line with the plan of action that you've already determined prior to "asking" the question that you apparently don't want answers to, you make up a bunch of reasons why your plan is right anyways.

    Take it for what it's worth, but more listening and less talking generally never hurt noone...
    Cheers!

    However you could HELP me, I do not know what an EBSTCM is and have never heard of adjusting the "pedal height" on a vehicle. And how whatever that is could be related to replacing the brake pads and rotors.
     
  14. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

    Age:
    22
    Posts:
    3,440
    Likes Received:
    1,920
    Joined:
    Sep 8, 2019
    Location:
    Northern Wisconsin
    First Name:
    Taylor
    Truck Year:
    1978, 1980
    Truck Model:
    K10, K25
    Engine Size:
    400(?), 350
    Oh, if you do a brake job on modern car like mine and the rear calipers have a different "distance" to engage than before you did the brake job you change your pedal height. so when changing brakes, you would pump brakes sitting still no engine running a few times to put the calipers squeezed up and then of course they would pull off slightly.
    just because of how the rear calipers rotate out and its all weird stuff, one side being off would still be strange because it needs more pressure to turn the one to the same "application" but with scan tool i can make that basically its default resting point and make the pedal higher(it would sit lower)
    I broke my phone but if i had a pic youd see my reason for sure resurface on the one because i forgot when my caliper bracket unbolted i had a LOT of breaking happen on HALF the surface and it realy caused a disturbance. when i check for spec and if its decent ill hopefully be able to get it trimmed to spec. the fronts have ridges from the PO not using any brake grease and pad was staying applied on the top half. (These 4 rotors are the best of my whole set visually and with digital caliper. ill get a micromoeter and get my spec
     
  15. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

    Age:
    22
    Posts:
    3,440
    Likes Received:
    1,920
    Joined:
    Sep 8, 2019
    Location:
    Northern Wisconsin
    First Name:
    Taylor
    Truck Year:
    1978, 1980
    Truck Model:
    K10, K25
    Engine Size:
    400(?), 350
    EBSTCM IS the eletronic brake system traction control module .

    TCS and ABS module in one. Delphi-Bosch V model. in my car it can be used to purge air from the system by activating solenoids and raise pedal height so you have more engagement with brake pedal.it also needs a tech 2 or other high level scanner to interface it. Im not disregarding what you are saying, i just have a hard time explaining what the rotors are doing without a camera atm. a simple way to explain it, the reasons i took them off cars before was because previous owners didnt know how to do brakes or take care of them. most had sticking pads that applied constant pressure and glazed pads and burnt rotors but not un-fixable, just so the surface was too smooth and had uneven wear
     

Share This Page