Front rotor brakes are gone and rubbed metal to metal for a few miles. How to measure without a micrometer

Lining thickness is dependent on a few factors. A. Is your lining bonded to the shoe or pad, or is it Rivited to the shoe or pad? B. What is the application? Lining thickness is determined ultimatley by the manufacturer. Generally speaking on Automotive and light truck applications new lining for brake shoes is between 6/32nds and 12/32nds of an inch. Add a couple 32nds if rivited. On front brake pads the lining is much thicker when new. On average a new brake pad can have lining between 10/32nds to 18/32nds. Pads are in need of replacement when bonded lining has worn to 2/32nd and rivited lining has worn to 3/32nds since the rivet head can come in contact with the disc brake rotor or drum at 1/32nds. Lining can also break free from the pad or shoe when they get that low due to rotor or drum out-of-round. This can cause lining to break free from the pad or shoe and cause dmage to the drum or rotor surface. When replacing brakes, its always good to have drums or rotors machined or replaced. For rotors, there are three specs to take into consideration. 1. Minimium machining thickness. If rotors are machined beyond their reccomended minimium machining they will warp due to heat. This warping will eventually lead to brake pedal pulsation. 2. Run-out; Run-out is measured using a dial micrometer and usually .003 to .005 of an inch is considered excessive. 3. Material Thickness Variation; or parralleism is measure with a micrometer. .0003 to .0005 ten thousandths of an inch is considered excessive. It is extremly hard to find a rotor that will pass all three of these measurements. If someone tells you the rotors do not need to be machined because they "look good", don't trust them because they don't know what they are talking about. Rotor condition can not be determined by the human eye. Drums have a maximium diameter they can not exceed, as well as an out-of-round specification as well. A good brake job will always have drums and rotors either machined or replaced. Money can be saved if they can be machined as it it cheaper to machine than replace.

sound like worn out brake pads worn down to the metal rubbing damaging brake rotors

check brake pads for wear and check to see if the brake dust shield is rubbing the rotor. Most are metal, but yours may be plastic.

Brake Disc (Rotor) REMOVAL & INSTALLATION

1. Raise and safely support the front of the truck with jackstands. Remove the front wheel.
2. Remove the caliper assembly and support it to the frame with a piece of wire without disconnecting the brake fluid hose.
3. Remove the hub and rotor assembly.
4. Install the rotor in the reverse order of removal, and adjust the wheel bearing as outlined in Section 1.

INSPECTION If the rotor is deeply scarred or has shallow cracks, it may be refinished on a disc brake rotor lathe. Also, if the lateral run-out exceeds 0.010 in. (0.25mm) within a 6 in. (152mm) radius when measured with a dial indicator, with the stylus 1 in. (25mm) in from the edge of the rotor, the rotor should be refinished or replaced. A maximum of 0.020 in. (0.5mm) of material may be removed equally from each friction surface of the rotor. If the damage cannot be corrected when the rotor has been machined to the minimum thickness shown on the rotor, it should be replaced. The finished braking surfaces of the rotor must be parallel within 0.007 in. (0.178mm) and lateral run-out must not be more than 0.003 in. (0.076mm) on the inboard surface in a 5 in. (127mm) radius. Fig. 1: Use a dial indicator and micrometer to check the rotor for run-out and thickness
Fig. 2: A correct final rotor finish
Fig. 3: Location of the rotor minimum thickness marking
Fig. 4: Exploded view of a rotor mounting to the hub — 4WD Dakota models shown

Not to question your ability, if you listen from the drivers seat while driving, just do yourself a favor, check the rear brakes, funny how sound travels and tricks the mind

Were metallic brake pads installed? If they were and are hidhly aggressive, yes. Give them a few miles to smooth out.

Have you checked the metal clips that olds the brake pads in the front galiper bracket. They usualy rust, break loose and come in contact whit the disc, creating a squeaking noise. Those should be replace since they are needed for the brakes to work properly

All shops will tell you that you need to turn or replace the front rotors when you do brakes. I personally only replace rotors, and only if I get shaking in the steering wheel when I apply the brakes. In answer to your question 75 to 125$ us for a brake job including pads and turning the rotors.

make sure the caplipers are doing their job properly. if the calipers are not functioning properly that will cause uneven wear as well as a dragging, as in the pads are not coming off of the rotor and therefore rubbing while you're driving. also, check to see that you are getting a pad that will wear without so much rotor wear. they make pads that will absorb more wear so that you don't have to replace the rotors every time you have your brakes done. And if that doesn't work... no joke, change your braking habits. unfortunatly, to many people wait till they're at the stop sign or red light to apply the brakes instead of preparing for the known. my brakes have been on my truck (HEAVY) for 50,000 miles (hard use) and have only begun to squeak in the last 100 miles. Changed my brakes completely and my braking habits. good luck