Calipers doesn't fit with my rotor - I'm lost

Hi all,

So basacly, I bought from 4 calipers to replace mine (they’re almost dead). I went to the mechanic this morning to install them, but surprise ! They are a bit too big : Only half of the brake pads touch of the rotor. For an unknown reason, I did receive a full set of rotor and brake pads (that I didn’t buy), but again, those doesn’t event fit on my car.

So my question(S) are:

1- Should I ask for new calipers or simply buy an other brand? I’m wondering if it’s simply a mistake from them or not.

2- Does the calipers should do on my car? It’s a Mazda 3 2010 GS 2.0

My rotors are : Raybestos 980285FZN and 980295FZN

The calipers that I order are:

Thank you very much. I’m quite lost on if I made a mistake or if it should fit

Not many mechanics really want people to supply the parts . They will not warranty the parts and you will pay labor to have them replaced if they fail. Just return the parts and let the mechanic do what you are paying him for.


Oh I know the mechanic actually :slight_smile: He has his garage and he’s the one that told me about Rockauto. I bought all of my stuff there, but it’s the first time it doesn’T work

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Since you can’t be bothered to give us the year of your car, do your own homework. Search Rockauto with the part numbers you have and see if they are for the year, model and type of car you own. Click on the part number in the RA listing and it will tell you all the cars it fits. You clearly have the wrong parts whether you ordered the wrong thing or the wrong part is in the correct box.

Since you received a rotor and brake pad set you say you didn’t buy, contact RockAuto. We can’t fix your or RockAuto’s mistake. That is your task.

I’d suggest you leave the parts ordering to your mechanic in the future as this is not going well for you.


Truly sorry, I forgot to mention the year of the car.

I did my reasearch actually, I was hoping to have some answer here too.

It seems that Rockauto mistakenly put the wrong part on the rear on 2010 model car, and it seems I might have received a wrong part in a correct box (I need to confirm however).

But thanks for the answer

Sometimes that happened that wont work that way,done some of it many years back just return it but hustle/cost,best is buy set up locally like autozone,oreilly"s ,NAPA if any issues easy to return/refund or get the right one,best bring old pads and rotor in the store to compare,little more expensive sometime those 20% off or 10% off help’s if they promo like that,since I’m DIY that I always do.One example is the rear pads replacement of 2018 mazda 3 with 2.5l,USA or Mexico make of car to choose which one.

That sentence needs a little editing to really make sense . Who takes the pads off before they have new ones to put on ?

Generally speaking . . . I’m sure there are exceptions . . . I don’t believe it’s a good idea to let the customer source the parts

Unless the vehicle in question is rare, the mechanic’s probably better at finding the correct parts for the particular application

This may involve much more than simply ordering parts based on model year, VIN, etc.

it may include physically verifying what the car has installed BEFORE ordering parts

I work only on fleet vehicles

And what’s on the truck is frequently NOT what Rockauto says is on the vehicle

ALWAYS verify what you need before ordering

I’ve seen many guys ignore this and regret it later when the part shows up and isn’t correct for the application

See above . . .

Many vehicles have several brake options for a given model year

Best to verify what you need before ordering it

As one of the regulars said recently . . . this is the mechanic’s equivalent of “Measure twice, cut once”


Your car is on the hoist at the mechanics? Simply have him order the correct parts from his supplier and they will deliver them within an hour.

This is the reason Rockauto is for the driveway DIY crowd and not professional mechanics or businesses. If a car is tied up on a hoist waiting for parts that’s lost income to the tune of $2/minute. I can’t afford to save money on parts.


What does your invoice say? Do the part numbers on the box match it? Since you got parts you didn’t order, I wonder if they sent you someone else’s order.

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Fortunatly he reinstalled the old one for now. I know him so he’s been nice. I know Rockauto isn’t the best thing, but there is a HUGE difference in price. I bought from there a few time now and everything was perfect until today.

Yes it does. After doing some digging on Raybestos website, i realised that both front one aren’t well listed on Rockauto, and 1 rear isn’t the good one. The mechanic will try the “good one” that is exacly the one on the picture to see if it fits. If it does, well it confirms that the one we tried isn’t the good product sent in a good box

I work in a completely unrelated business (HVAC) and sometimes we get this kind of “logic” from customers as well. For example, some people don’t want to pay us $2500-3000 for a new Fujitsu/Daikin/Mitsubishi mini-split, and want to buy one of the cheap no-name ones online and have us install it, or complain about the cost of an expensive control board or motor and want to buy it online and have us install it to “save” money.

Well, guess what? We are a for-profit business, and part of that profit includes charging a mark-up on parts and equipment. The only time I really want to install parts or equipment that a customer supplies is if the customer is a commercial account which maintains a stockpile of parts and replacement units (for example some hotels and apartment complexes) or if the parts or equipment would be difficult for us to obtain (for example, repair parts for a unit purchased in another country).

Commercial customers which supply their own parts and HVAC units for us to install understand and accept the fact that we are only warrantying our workmanship, and not the parts or equipment which we did not supply. An average customer would not have this understanding, and it would not be profitable to do this type of work for a typical residential customer anyways. In commercial, the money is in volume, i.e. you don’t make much profit on each service call or installation, but you get a lot of business from the customer, which ends up being profitable.

Pretty much agree. I always verify what I got with what the old part looks like. I use Rock sometimes but I did get a Delco water pump that I had to have the dealer install after I failed. Pump leaked and dealer part was about the same price.

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This happens quite regularly in the automotive world:

“Hello this is Bob. I had my truck in for alignment last week and you found worn ball joints and tie rods. When can I get those fixed?”

“We can get you in Tues at 10. Let me look up your history here…looks like we quoted you $1150 and no charge to recheck the alignment.”

“Yeah but I have all the parts you listed so it will just be the $680 labor right?”

“No sir, we don’t do repairs with customer supplied parts. We’ll do the job but with our parts for $1150.”

“Well I bought the parts from Amazon for less than half what you’re charging me!”

“OK, did Amazon quote you a price to install them?” Etc, etc, etc.

Now we will occasionally make exceptions. When I had my own place I had a customer with a 62 Bentley. It was a “wedding car”, people would hire him to drive for their weddings, prom, etc. One day the car was in and needed some brake parts. He said he had the parts we needed, brand new, at home. I gave him my shop truck keys to go get them.


Yes, sometimes if you search online you can find a 25% off discount at Advance Auto parts order online pick up in store.

Yeah but if he’s a friend of the mechanics and everything you know he’s paying him for labor I’m sure he understands that the mechanics not going to warranty the parts that’s between him and RockAuto I know everybody’s garages HVAC plumbers what have you mark up prices sure…
But this is a different case if the mechanic don’t care I don’t know why you all jumping this guy’s butt?
He wrote on here to try to get a little help not to get jumped on.

Wouldn’t it be nice if mechanics would give you two choices: one price if they buy the parts (and honor the warranty) and another price if you bring them parts. Disclosing hidden profits would let their customers make wiser decisions.