Front Brake Rotor Check

[MDJEEPER]

Does anybody know of a way to check the front brake rotors without a fancy, smanchy micrometer?

Just trying to figure out whether I need to replace just the disc pads or must also deal with the rotors....

 

[IOPort51]

Does anybody know of a way to check the front brake rotors without a fancy, smanchy micrometer?

Just trying to figure out whether I need to replace just the disc pads or must also deal with the rotors....

Can some one explain to me why you would turn rotors? I have never understood the whole concept except it reduces the life of the rotor. I have never had one turned. If the thickness drops below the minimum resurface thickness will the brakes stop working??

 

[IOPort51]

A micrometer is a handy thing to have, you should own one. don't buy a digital, when you need it the battery will be dead. Dial calipers are cool too.

Does anybody know of a way to check the front brake rotors without a fancy, smanchy micrometer?

Just trying to figure out whether I need to replace just the disc pads or must also deal with the rotors....

 

[Sasquach]

If they become out of true..wobble for lake of better term beyond a spec. limit they need to be turned to make true again. Ever have a vehicles steering wheel shake when you step on the brakes?

 

[Sasquach]

Does anybody know of a way to check the front brake rotors without a fancy, smanchy micrometer?

Just trying to figure out whether I need to replace just the disc pads or must also deal with the rotors....

Without a micrometer...If you don't get wheel shake when you get on the brakes and the rotors look good..no grooving etc, then I just leave them alone and do the pads if needed.

Acctualy it's a dial indicator that you need.

 

[Old Dog]

If the thickness drops below the minimum resurface thickness will the brakes stop working??

I have seen vented ones get smached. But they were way under min. thickness.

 

[Old Dog]

Without a micrometer...If you don't get wheel shake when you get on the brakes and the rotors look good..no grooving etc, then I just leave them alone and do the pads if needed.

Acctualy it's a dial indicator that you need.

A mic. is used to measure the thickness, an indicator will measure runout. So both would be handy.

As said, if the rotors look good, and don't shake the steering wheel when the brakes are applied, get the pads and be done.

 

[Buuushman]

If you really want them checked without buying a micrometer, take them to your local parts store- they will mic them, tell you they are 10000th shy of being turnable, and sell you new ones.

 

[Cheepjeep85]

i payed $35 a piece for new rotors, so they are pretty cheap if you need em. i took mine to a local brake shop and asked em what they charged to check em out they said nothing they mic'ed em and said they was bad i bought new ones, done

 

[IOPort51]

i payed $35 a piece for new rotors, so they are pretty cheap if you need em. i took mine to a local brake shop and asked em what they charged to check em out they said nothing they mic'ed em and said they was bad i bought new ones, done

mine are $85 each, I think these are unique to the 77-78.

 

[Old Dog]

mine are $85 each, I think these are unique to the 77-78.

is that for the rotor and hub all in one?

 

[IOPort51]

is that for the rotor and hub all in one?

just the rotor, they are about 3/4" thick with a vented center.

 

[TDHofstetter]

A long time ago I pulled my brakes apart because they'd been making grinding noises for about 15,000 miles (I was dirt poor, OK?) and found that the rivets in the pads had made huge deep grooves in the rotors. STILL being dirt poor, I queried... and thought. Both rotors had about the same groove depth & severity.

I bought new semi-metallic pads & put 'em in, LEAVING the grooved rotors in place. The grooves in the rotors quickly ground ribs (well, everything BUT the ribs) into the new semi-metallic (lifetime warranty) pads and settled down.

Brakes worked just fine for another ten, twelve years of everyday hotrodding. Looked like CHIT, but worked just fine.

If they hadn't been matched, I'd never have gotten away with it - they'd have dragged hard to whichever side had the worst grooving.

Even if rotors are warped, it's not so bad - the calipers are built with some movement in mind. The worst case is when the rotors' thickness isn't constant all the way around, usually because of inconsistency in the iron they're made of. THAT will kill ya on a winter's night.

 

[IOPort51]

I have a very similar story at least about the “too broke to pay attention” part but I just grooved one side and yes I drove it for several years and no it never pulled to the grooved side that I noticed. Or the un grooved side. I would say that constitutes more surface area for pad contact and heat dissipation. In fact I just recently replaces that rotor and it is in the scrap metal pile in the shop as we speek.

A long time ago I pulled my brakes apart because they'd been making grinding noises for about 15,000 miles (I was dirt poor, OK?) and found that the rivets in the pads had made huge deep grooves in the rotors. STILL being dirt poor, I queried... and thought. Both rotors had about the same groove depth & severity.

I bought new semi-metallic pads & put 'em in, LEAVING the grooved rotors in place. The grooves in the rotors quickly ground ribs (well, everything BUT the ribs) into the new semi-metallic (lifetime warranty) pads and settled down.

Brakes worked just fine for another ten, twelve years of everyday hotrodding. Looked like CHIT, but worked just fine.

If they hadn't been matched, I'd never have gotten away with it - they'd have dragged hard to whichever side had the worst grooving.

Even if rotors are warped, it's not so bad - the calipers are built with some movement in mind. The worst case is when the rotors' thickness isn't constant all the way around, usually because of inconsistency in the iron they're made of. THAT will kill ya on a winter's night.

 

[nitor]

If they become out of true..wobble for lake of better term beyond a spec. limit they need to be turned to make true again. Ever have a vehicles steering wheel shake when you step on the brakes?

If the brake rotors get to hot they warp. Warped rotors cause the steering wheel to wobble when the brakes are applied. The rotors are turned to true them up so this doesn't happen.

I knew a guy in the past that let his rotors get so thin (he thought he was being taken at the brake shop when they told him they were dangerous) that the brake pad wore through the rotor. The fins in the middle of the rotors ate through the piston on his calipers when he applied the brakes. He lost all brakes because when the caliper piston was gone the fluid came out. He couldn't stop when he pressed on the brakes. He almost killed himself.

 

[LongHorn]

Can some one explain to me why you would turn rotors? I have never understood the whole concept except it reduces the life of the rotor. I have never had one turned. If the thickness drops below the minimum resurface thickness will the brakes stop working??

Sometimes they warp & cause vibration.
Also your suppose to break the glaze.
On most new cars that's not an option, you throw away & re-place.

 

[Sasquach]

If the brake rotors get to hot they warp. Warped rotors cause the steering wheel to wobble when the brakes are applied. The rotors are turned to true them up so this doesn't happen.

I knew a guy in the past that let his rotors get so thin (he thought he was being taken at the brake shop when they told him they were dangerous) that the brake pad wore through the rotor. The fins in the middle of the rotors ate through the piston on his calipers when he applied the brakes. He lost all brakes because when the caliper piston was gone the fluid came out. He couldn't stop when he pressed on the brakes. He almost killed himself.

That must have sounded pretty horrible?

 

[nitor]

That must have sounded pretty horrible?

He couldn't stop the car. Went into a ditch and rolled it. I don't even remember what the car was. I think it was some sort of a mid size. Anyway, he wished he had listened to those mechanics at the brake shop after that.