What dimensions is the brake rotor guide pin?

diplomaticm3 · Post by **diplomaticm3** » 17 Oct 2019, 18:56

Anyone else use a substitute from a hardware store? I find it hard to shell out $80 for 4 x small pins.

Thanks in advance.

Post by **jimmy57** » 17 Oct 2019, 20:30

6mm-1.0 bolt 15 mm long
They are optional. the pin on head was to assure the wheel went on in one place if it were dynamically balanced on the car. That has not been done by tire stores in 25 years or longer. The bolt was used to hold rotors onto hubs for shipping prior to new vehicle manufacture. They are a mild convenience when you remove brake pads for pad change other rotor and hub repairs. If you leave them out nothing will happen. You may have worked on an American made car and found a round odd washer with rolled up "fingers" on the inside diameter. Those were for the same purpose, they hold drums on axles for shipping prior to vehicle build. Once removed they are not replaced as they have no purpose.

diplomaticm3 · Post by **diplomaticm3** » 18 Oct 2019, 00:23

Really? Huh...that’s good to know.

I was under the impression that they “center” the rotor and prevent warping. But now that makes less sense to me as I’ve had other cars with this item removed & nothing happened.

Post by **erikv11** » 18 Oct 2019, 09:48

For me they are more of a mild inconvenience, making sure the wheel lines up.

Post by **jimmy57** » 18 Oct 2019, 14:12

On P3 they went with countersunk screws for this so you lose that assistance.

Post by **abscate** » 19 Oct 2019, 07:42

erikv11 wrote: 18 Oct 2019, 09:48 For me they are more of a mild inconvenience, making sure the wheel lines up.

On my steelies, the pins are great as they help hold the wheel on as I replace.

For my alloys , they go into a single blind hole so they are a bit of a hassle

I guess they are like bacteria, some good , some bad