New brakes, still shaking.

From time to time we get those cheap Chinese dial indicators that come in for calibration and the analog versions rarely ever pass accuracy, repeatability, and linearity checks. They are usually spec'd at +/- 0.001" like the decent analog Swiss made SPI for example and are pretty much junk. The cheap Chinese digital dial indicators aren't much better. I have seen both types with more than .002" error and linearity error up to .004" new out of the box. 1 out of 20 might pass verification. Some auto parts stores will lend out dial indicators to check run out that are quality but usually not calibrated since mfr date. Just throwing this out there to take into account when making precision measurements with tight specs approaching the accuracy limits of the measuring tool being used.

 

How and why did the pins bend?

 

If I were a machinist using precision instruments every day in my work, I would use instruments suitable to those skills like Starrett, Browne & Sharp, and Mitutoyo. For measuring bearing journals, you need professional tools, and they should be handled with care.

For determining if my rotor is wobbling, or verifying fastener diameters, cheaper Chinese tools have served me well. The digital caliper I have is spec'ed to +/- 0.001". From my experience measuring known dimensions, that digital caliper (a high quality repro of a Mitutoyo) meets or exceeds that standard. I preserve the calibration by not dropping it, throwing it around, and by keeping it in the case without the battery installed.

What is the 0.002" error you speak of?...Is that over the range of the instrument? For a dial indicator reading of 0.002"-0.010" travel, the error would have to be some percentage the travel to be relevant. If the dial indicator reads 0.001" for every 0.002" actual travel (error of 100%) that would be unacceptable. If the indicator has 20 percent error, i.e. reading 0.0008" for every 0.001" travel, that would probably not change the conclusion that rotor wobble is out of spec.

I have no doubt that some, or maybe most, Chinese precision measuring tools are poor quality. Readers be aware; the burden of knowing the limitations of your tools rests squarely on the craftsman.

 

I said so in the first paragraph of the post

Not sure. I’ve only had the truck for a little over 2 years. About a year ago I took the rotors off and had them turned due to the vibrating issue. Re-used the pads because honestly they looked almost brand new. Thinking about it now, I remember the pins being bent then but didn’t think too much about it at the time. Now it makes sense why the vibration came back after that try of turning them. They felt great for about the first hundred miles or so but the vibes came back not long after that. I chalked it up to the rotors being too far gone to save.

 

Good news: put some miles on it after parking it for the last couple days. It seems the new pins and moving the pads around have solved the issue. No more vibrating while braking. Instant improvement and resolution to my issue.

 

Well...Did you get the rotors turned? Or, did simply replacing the pins totally reverse all the ill effects of rotor warping?

I would've left it alone to punish myself for having such a careless, penny-pinching brake technician. JK...

 

Oh.. just cut it and you should be fine.


Edit: I should read, if no vibes anymore, your fine lol

 

You could just as easily use a piece of bent coat hanger to check runout and warp as opposed to those expensive Chinese tools..;-)>

As to the craftsman problem, that's why I only use Snap On...

hth,
B

 

• We have had new non branded Chinese dial indicators measure out of spec right out of the box. After a zero set reference the indicator is checked at various predetermined setpoints depending on range. After zero set it's not uncommon at all to get the significant errors that I previously mentioned. In some cases these indicators can be adjusted into spec depending quality of the internal movement assembly. We utilize Mitutoyo stands and Mitutoyo and Meyer Gage Blocks traceable to NIST. Our local physical/dimensional lab processes thousands of calibrations yearly and can attest that the cal techs aren't to fond of knock off Chinese hand tools just as I dislike calibrating knock off Chinese test & measuring equipment. Sure, some of these non branded Chinese tools may suffice for measuring run out for example but we have the luxury and satisfaction of being able to verify the accuracy of our own personal hand tools against traceable standards and we actually know if our personal tools are in tolerance. We had a customer bring in six brand new in box Harbor Freight 6" digital calipers. NEW.... Four of the six failed initial calibration but were able to be adjusted into spec. Could have been a bad batch but we have seen the same issues with Chinese torque wrenches that get turned in. OOT right out of the box. To complicate things..some Chinese test equipment/hand tools are better than other Chinese sourced tools. Herein lies the main problem......NO WAY OF KNOWING THE SOURCE, at least true with Chinese hand tools. Very hard to next to impossible to get parts so repair is usually by replacement. This is something we deal with every day in a calibration lab. As mentioned it is important to know your tools' potential limitations for the measurements you will be making. If you DIY it's good to get your hand tools verified if you use them a lot and even the top tier tools can go out of tolerance.

 

That's good to hear and hopefully the vibes stay away

 

No I didn’t mess with the rotors. I figure only a couple hundred miles the uneven wear would be so minimal so fixing the underlying issue would be enough.

BTW I put the brakes on on Christmas Day. So it wasn’t that I was careless but I didn’t know I needed new pins before I started and couldn’t have gotten new pins that day even if I wanted to.

 

Jerkin' yer chain in jest. Glad you got the bugs worked out.