I replaced my rear brake pads today. I tore the dust boot in the caliper slightly. Is this going to cause a problem. It looks like it is only there to keep dirt and dust out.

 

Yes...

Once the dust boot is breached, fine particles of brake dust and dirt from the road as well as water if you drive in the rain, find their way onto the piston and can cause an inner seal failure and system contamination.

 

Can the boot itself be replaced/repaired?

 

It is often more of a PITA to replace the caliper boot than worth. Buy a remanufactured caliper, not the complete set. They do have kits to replace the boot, but it requires using an air nozzle to blow out the piston, removing the boot, replacing the caliper piston seal, putting the boot back on and using your air nozzle to push the boot around the caliper piston until it is in place again. I've done it only once and swore I'd buy a reaman'd caliper next time. You'll also find the cost of a reman'd caliper is worth it.

 

You must correct the problem immediately.

Replace the old unit with a new remanufactured caliper. When you replace calipers, you must do so in sets. With exchange, the price should be between $50-$100/caliper.

 

Yeah, your brakes are the last thing you want to have problems with on your car.

 

Do I reaaly need to replace both calipers at once?

 

Yeah, it is the smart thing to do. Reason.... your new caliper will perform better than the old one on the opposite side. Brake fluid leaves a type of "slug" on the inside of the piston as well as other deposits. This decreases its performance over the life of the caliper. Call around, but I'd say it is worth it to do both if you think about the potential consequences. Also, you'll need to do a brake flush... if that wasn't immediately obvious.

 

Correct, you should always replace both sides.

If you only replace one side, one side will be restored to OE specifications and the other would not. You risk having a pull develop.

 

place both. rebuilding those(actuated) are a PITA.

 

I will go out on a limb here and say there's really no immediate need to replace or rebuild the caliper if it has just a small tear in the dust boot. The chances of any significant dirt getting past a small tear and into the piston seal is slim to none.

It's pretty simple, inspect that caliper carefully any time the wheels are off and if you see signs of fluid leakage, rebuild or replace it.

BTW the rear calipers are not particularly easy to rebuild, as the e-brake mechanism is fairly complex.

And unless the brake hydraulic system in the OP's car is especially filthy I don't see a need to replace calipers in pairs. I never have and have never had anyone return with a "pulling" complaint after.

 

I agree - replace the damaged caliper and leave the rest of the system as is. There is no need to replace the mate unless you have a compulsion to throw your money away.
Spend it on a complete fluid flush instead.