Problems with 2005 Mazda3 replacement brake caliper

It is a 2005 Mazda 3 with a 2.3, according to a VIN lookup at the ford site, and I'm the original owner.

I ordered a refurbished front-right caliper using a store's online vehicle lookup and the caliper they sent doesn't match the one that came with the vehicle. The information on the left side of the original caliper is: "FoMoCo, 7, 390, RH", and there is "814" at the top. The new caliper is: "FoMoCo, 8, 3Z3, RH" with the "814". Also, the original mounting bolts have a courser thread than the new mounting bracket.

I looked online for a refurbished "FoMoCo, 7, 390, RH, 814", but I wasn't able to find a caliper with that information. Does anyone know what these numbers mean and how to find the correct replacement caliper?
2010 Mazda 5 Sport
Go to

Put in your vin. <-Important! This will filter out all but your model/trim.

Search the diagram pages for the correct OEM part number. Check the pictures if they have them to verify that's the correct part. If you can't figure it out, CALL THE DEALER. They will take your vin and give you the part number. You don't have to buy it from them.

Google that OEM part number and see if any aftermarket calipers pop up and verify against at least 2 sites. Or buy from Mazda...lots of discount Mazda dealers sell parts 30% off. I've used MazdaSwag. Mazda dealer will want your vin and they will check it for fitment.

I use google image search and ebay to help me determine if what I have on my car looks like the part number
2014 Mazda3 S GT auto, 2008 MX5 6-speed
Did you cross reference the manufacturer's part number? Here's an example:
The screw thread difference you are seeing is very odd. I believe that many critical screws are fine thread but it's be good to get your hands on one from a dealership to verify.

Thank you for the replies. I started up on the problem today, putting my VIN# through the parts suppliers, and found this at
Screenshot from 2021-08-24 18-49-30.png

This got me thinking... my door label says the car was built in Japan in 11/2004 and it is a Mazda/Ford hybrid that just started selling, so maybe they were pushing to meet demand and that is why the mounting threads are different, but that the caliper itself should respond the same as the three existing calipers (which was my main worry).

Going with that idea, I mounted it using the old mounting bracket with the new caliper. I was comfortable with how the reassembly went and after a road test, all four discs felt about the same temperature (hot, but not finger burning hot).

I also used this useful post to bleed the brakes.

Thank you!
2014 Mazda3 S GT auto, 2008 MX5 6-speed
That's great news. Hopefully you noticed my cautionary statement in response to the brake bleeding post, regarding pushing the brake pedal to the floor - NOT recommended.
I had not read it before I bled the brakes. I think I avoided pushing it to the floor by luck.

When I bled them, I was most worried about pushing air bubbles into the system by working the pedal too fast, so my plan was to push in the fluid slowly. With the bleeder valve finger-tight, I pushed the brake pedal down at a gentle rate to pressurize the system (gradual pressure on the brake pedal until there was back-pressure like I would have if I was parked in neutral on a hill at a light, probably between 50% and 75% distance of the pedal range). Once the pedal was there, I propped a long pipe between the pedal and the front seat to hold the pedal in place, I finger-loosened the bleeder so it was not full flow but could let something out, held it there for about 2 seconds and then finger-tightened it again, and went back to the brake pedal for another push. I did that many times until loosening the bleeder gave consistent fluid then did it twice more.

Since bleeding the brakes, I put about 250 non-highway miles on the car and my clutch slave cylinder just died a fast death. I'm not sure what to think of that, but I am going to be careful with bleeding that system, I believe the advice about avoiding pressing the pedal to the floor can be applied to any not-new system with a cylinder pump. Once any piston works for some time, it will build up a high-water mark and that is where debris can build up, the debris that will damage the piston seals if you suddenly force the piston past that high-water mark.

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