Casting Holes in a Ford Rotor

[Boomer]

I parked next to a fairly new small Ford SUV this AM when I took my wife in for a Covid test as she has cataract surgery next week. I waited in the car. As I looked at the Ford, I noticed all these various sized little dark marks on the rotor that looked like black particles ranging in size from a pencil point to a small pea. So I got out to look closer. Imagine my surprise when I realized that these were actually pits in the surface of the rotor. Some were quite deep and there were at least 50-60 of these on the rotor surface on the side that I could see! Basically, this rotor looked like a metallic Swiss cheese. How many "bubbles" were still beneath the surface waiting to be exposed as the rotor wore down? This looked very unsafe to me. Judging from the age of the vehicle, these were probably OEM rotors as it came from the factory.

Has anyone else ever seen anything like this? I would think a rotor like this could be quite unsafe.

 

[Kira]

If nothing else it'll make calculating the "swept area" more difficult.

Seriously though, you're looking at bad QC. 'Tis a shame.

 

[KGMtech]

Never seen this, but as Kira said, that batch of cast iron was bad.

 

[Zee09]

Cheaper than cross drilling

 

[skyactiv]

Maybe they are dimpled rotors.

 

[Skippy722]

Porosity, it happens in castings. Happens to us at work... sometimes they’re right on the surface, other times you have to remove some material to notice them.

 

[wemay]

This thread is from '06 to '15...

Pitted Rotors - F150online Forums

Wheels, Tires & Brakes - Pitted Rotors - Went to change the front pads on my '99 F150 Super Cab 2WD, 4w/ABS. It only has 55K miles on it and the brakes are original. The rotors were Deeply pitted over the Entire surface of the inner braking surface and, from what I can see of the other front...

www.f150online.com

 

[AutoMechanic]

Never seen that happen before on any vehicle.

 

[JohnnyG]

Seems to be common these days. I have one on the left rear rotor of my 2018 E300, and I've seen a few on cars parked next to me. I don't really think it will hurt anything, but it appears that Chinese competition is really hurting quality control elsewhere as well. What used to be rejected is now "acceptable".

 

[TWar]

I have come across 2 rotors in the past 10-15 years that have had that problem. One was on the surface of a brand new rotor and I exchanged it before leaving advance. It looked like a crack in the shape of a half circle half the size of a dime. The second with the porosity issue had it deeper and exposed within a year. That one looked like Swiss cheese with little flakes missing on both sides all around the rotor. It was very noticeable when braking.