Caliper for checking brakes as a tech

[tomalophicon]

I havnt measured a rotor for 40 years, a guy can look at them and see if they are fit for service, same for pads.

You measure them with your eyes? That's a gift.

 

[sberry]

You measure them with your eyes? That's a gift.

No but can look at a common rotor and asses if its work out junk and needs a new one. Had one in the other day, the passenger got jammed with gravel and ruined it, just wore it right off. Could measure the difference between right and left with a construction tape.

 

[tomalophicon]

No but can look at a common rotor and asses if its work out junk and needs a new one. Had one in the other day, the passenger got jammed with gravel and ruined it, just wore it right off. Could measure the difference between right and left with a construction tape.

How are you measuring undamaged rotors for spec though? I want to learn your skills!

 

[2ndGearRubber]

How are you measuring undamaged rotors for spec though? I want to learn your skills!

Sberry lives in the salt belt. Rotors don't last long enough to make it to minimum thickness.


Euros are almost universally one and done, since the rotors are so soft. I can't imagine anyone taking the time to cut 20thou of dish off each side before you can take a proper pass.

Domestic/asian car rotors get rust damaged pretty quick, VERY rare a rotor can make it through 2 sets of pads without de-laminating/chipping/rusting over.


At then end of the day, is management or yourself going to refuse a gravy brake job because the rotors are below discard? Unless the rotor is visibly below spec (grinding brakes) or the fins are gone, would you or management refuse the pad slap? A proper brake job means cutting or replacing rotors. Most of the time rotors are comparable in price, and they're WAY faster to just swap out. Unless it's a super pricey rotor, I'd rather just swap them and move onto something else then babysit our low-powered lathe. But if a cheap-o wants a pad slap, and cheap-o customer DGAF about thickness on a rotor, who am I to deny? It's a half *** job anyway, so who cares how thick the rotor is? I guess I'm saying poor people (and cheapies) need brakes too, and unless they're blatantly falling apart it'll be fine.

 

[ChrisLS8]

Who turns rotors anymore?

 

[2ndGearRubber]

Who turns rotors anymore?

Also my point.


Unless the rotors are blatantly dangerous, ready to break in half, 100% rust, or otherwise FUBAR - replace them or pad slap 'em.

 

[eyeball]

I'd skip digital:



https://www.amazon.com/dp/B00NI1N3S4/?tag=atomicindus08-20



Or if you want to get fancy:



https://www.misterworker.com/en-us/facom/disc-brake-vernier-caliper-df18-01/6424.html

Out of curiosity why skip digital? I find even cheap digital to be accurate enough for the job described and batteries are plentiful and cheap.

 

[tomalophicon]

Sberry lives in the salt belt. Rotors don't last long enough to make it to minimum thickness.


Euros are almost universally one and done, since the rotors are so soft. I can't imagine anyone taking the time to cut 20thou of dish off each side before you can take a proper pass.

Domestic/asian car rotors get rust damaged pretty quick, VERY rare a rotor can make it through 2 sets of pads without de-laminating/chipping/rusting over.


At then end of the day, is management or yourself going to refuse a gravy brake job because the rotors are below discard? Unless the rotor is visibly below spec (grinding brakes) or the fins are gone, would you or management refuse the pad slap? A proper brake job means cutting or replacing rotors. Most of the time rotors are comparable in price, and they're WAY faster to just swap out. Unless it's a super pricey rotor, I'd rather just swap them and move onto something else then babysit our low-powered lathe. But if a cheap-o wants a pad slap, and cheap-o customer DGAF about thickness on a rotor, who am I to deny? It's a half *** job anyway, so who cares how thick the rotor is? I guess I'm saying poor people (and cheapies) need brakes too, and unless they're blatantly falling apart it'll be fine.

Crazy - totally different to my area - no rust whatsoever - I eek out every last micron - but yes - with the cost of rotors machining makes little sense.

 

[Indexmill]

What is this talk of turning rotors?

 

[WittHay]

I havnt measured a rotor for 40 years, a guy can look at them and see if they are fit for service, same for pads.

I agree but it depends on the area. We had 1 snowfall this year and salt/ brine solutions were used on the roads for about a week. 55° and grass growing now. Rotors last a long time

Some CVSA and NSA truck inspection and maintenance reports require that the rotor thickness be recorded. Also some rotors are inboard requiring hub removal and studs pressed.

A rotor gauge is a cheap tool for a mechanic to have when dealing with cheapskate customers and liability. An actual measurement goes further than saying the rotors are getting thin when somebody wants a pad replacement only

 

[928'er]

I'd just get a cheap HF pair and grind some material off to clear any lip worn into the disc. Down and dirty - it ain't rocket science.

 

[pelletman]

What ever you buy, make sure they aren't parallel flat jaws. They need tips on the end to reach past any lip worn in on the rotor. But usually if there's a lip the rotors is pretty much shot at that point.

I used a Fowler that I got at Autozone but it got smashed when I loaned it to a friend. Not sure why I do that...

https://www.autozone.com/clamps-and...h-rotocal-with-twin-conical-anvils/186492_0_0

V/R
Bogie

And he didn't buy you a new one? I'd get a new friend

 

[Rabid Badger]

Out of curiosity why skip digital? I find even cheap digital to be accurate enough for the job described and batteries are plentiful and cheap.

Two reasons:

1) This application doesn't require extraordinary accuracy.

2) A vernier doesn't have any electronics to go bad. It's pretty much the only "buy once, cry once" solution.

 

[unslow1]

I havnt measured a rotor for 40 years, a guy can look at them and see if they are fit for service, same for pads.

The last time I saw a rotor get measured was in tech school. Living in the rust belt they tend to disintegrate.

 

[mfewtrail]

I'd just get a cheap HF pair and grind some material off to clear any lip worn into the disc. Down and dirty - it ain't rocket science.

They sell a long reach caliper.

https://www.harborfreight.com/6-in-long-reach-digital-caliper-63714.html

 

[ClappedOutBport]

The following is more than enough.
https://www.harborfreight.com/6-in-long-reach-digital-caliper-63714.html

While it's understandable to spend big bucks on a tool for critical applications, spending $600 for measuring a rusty/dusty rotor (often cheap to buy new) is a total waste.

I use this to measure rotor thickness. It's more than 10 years old from Harbor Freight. Find two flat objects, stack them together and measure with the caliper, hit "zero" button, then place the objects on each side of the rotor, the read out is the rotor thickness. I use coins, but for a professional, two megnets might be better.

I'd just get a cheap HF pair and grind some material off to clear any lip worn into the disc. Down and dirty - it ain't rocket science.

That's exactly what I'd do. A little visit to the grinding wheel and be off.