disc spindle gasket
I don’t even run the shields since they serve no purpose if you’re not running the car in winter or off-road.
They're practically useless all the time. Some cars come straight from the factory without them nowadays, it's not unusual for them to not be part of a disk brake design.
I've run my cars on gravel roads and during the winter. All the shields do is trap heat, brake dust, and other junk near the rotors. I've gotten several pieces of gravel stuck in the shields on my Mopars as well as other makes and models. Nothing like getting a rock stuck between the shield and the rotor for some terrible screeching noises and rotor damage.
The shields do keep water off the disc in rain. Yes that is only one side, but that side can reduce brake efficiency for a bit until the water gets out from behind the pads. I tried this on a car with solid discs and filled my shorts during a quick down pour. I left the shields out thinking I would get better brake cooling.
I've been driving my Mopars without shields for over a decade now and 100k+ miles, year round. I've been in plenty of downpours without significant loss of braking. A light splash is all that would be repelled by a shield, any significant amount of water will have no issue going around and between and depending on your wheel style you might get much more water from the outside than the backside anyway. My enkei's for example have a TON of open area to the outside of the car, there will be a lot more water coming off the fenders, off other cars as spray, not coming in from the suspension side. If standing water on the roadway is the issue you should have light pressure on the brakes as you go through it anyway to keep water off the friction surfaces and some heat in the brakes, wet weather driving 101, true for drums and disks (although much more necessary for drums). A perfect time to do a little light, left foot braking while maintaining speed.
Heck, one of the reasons why drums suck in wet weather is
because they're so shielded, if water gets in there it stays. If water is getting into drums a goofy shield on one side only, with access holes cut in it and with a 1/4" standoff from the rotor isn't going to keep it out.
