With maintained disk brakes, what are the pros and cons of removing the backing plates? Sure would make suspension and maintenance easier.
Or maybe cut most of the plates away?
With maintained disk brakes, what are the pros and cons of removing the backing plates? Sure would make suspension and maintenance easier.
Or maybe cut most of the plates away?
The plates keep radiated heat away from your tender ball joint boots and help direct cooling air where it's needed on the disk. There are likely other important reasons but those two alone should convince you to keep them in place.
Edit: consensus is that most backing plates do not help with rotor cooling
Cold puddle of water splashing part of hot rotor and the resulting thermal stress/warp/cracking that ensues.
It also greatly reduces how much of your suspension gets caked in brake dust.
GameboyRMH wrote: It also greatly reduces how much of your suspension gets caked in brake dust.
I am pretty sure that is the only reason.
Our brakes on our race car run MUCH cooler with the plates off.
Water can get splashed on the outside of the rotor, which is just as bad.
Rob R.
^Keeping heat away from the ball joints and CVs & boots is definitely another valid reason.
Your shocks might pick up more radiated heat too.
I'm waiting for Angry Corvair, our resident automotive brake engineer, to chime it.
Radiated heat would only be a problem if you got the brakes very hot and then parked the car, then the heat may effect your ball joint boots and/or CV boots. If the car continues to move after hard braking I don't see how that heat will effect these part as the motion of the air will continue to keep these part cool. I have raced both FWD and RWD cars and have never seen any damage occur to these parts and I always remove the "splash shields". That is the correct term to call them, not dust shields. The factories install them to keep mud & snow from the brake rotors & calipers.
Water splashing on a hot rotor does not warp them. Try putting water in a very hot frying pan and see what happens, the water just "dances" on the surface as it turns into steam. You would have to dunk the whole rotor into water to have an effect.
Mine are rusting away, so I should be able to let you know in a year or two. 
I race in the rain or shine. A little water does not hurt naked rotors that are glowing red hot. It does cake everything in a rusty haze of metallic pad dust that sticks to painted surfaces like power coating though. It also might negatively effect rubber/plastic stuff in the very near vicinity but I doubt it. I know it does not bother rod ends or ABS wiring.
ansonivan wrote: The plates keep radiated heat away from your tender ball joint boots and help direct cooling air where it's needed on the disk. There are likely other important reasons but those two alone should convince you to keep them in place.
The only way it's directing cooling air anywhere is if there is a hole in it with ducting hooked up.
z31maniac wrote:ansonivan wrote: The plates keep radiated heat away from your tender ball joint boots and help direct cooling air where it's needed on the disk. There are likely other important reasons but those two alone should convince you to keep them in place.The only way it's directing cooling air anywhere is if there is a hole in it with ducting hooked up.
94-96 9C1 Caprices had special backing plates on the front with little scoops on them that directed air from the 9C1 specific chin spoiler to the rotors to cool them... so sometimes they do something besides keep debris off of the rotors...
Like jimbbski said, splash shields to keep water away from brakes. All my track cars get them removed. I have noticed a difference in pedal feel while driving in the rain with them off. So they do something.
If your vehicle sees any DD duty in the winter/rain, you should probably keep them on.
My summer DD had them removed as they were approximately 2" too short for the rotors and were in the way.
Brakes don't work so good in the rain anymore.
Other than that, f'em.
In reply to Type Q:
no way, man. i'm staying out of this.
just kidding.
from the OE side, consider this: if i could eliminate two part numbers from the bill of materials for my vehicle, plus the associated cost and weight savings from deleting those parts, i'd be a berkeleying hero.
the reasons OE's use them have all been touched on by previous posts. it's a combination of splash and gravel /dirt protection, thermal protection for suspension parts (don't want to liquidate all the ball joint / tie rod end grease or burn off the boots), and airflow management.
If they are there for the betterment of the backside of the disk, then someone please explain why when I do brakes, the outside of the disc is perfectly smooth, and the inside is scratched to the point where the rotor is scrap!
Based on this evidence, I propose that they are put in place to collect and hold gravel and moisture so that the vendors can sell more brake disc!
Glad we got that settled.
NOHOME wrote: If they are there for the betterment of the backside of the disk, then someone please explain why when I do brakes, the outside of the disc is perfectly smooth, and the inside is scratched to the point where the rotor is scrap!
That's because the caliper pins siezed and the pads rusted to the hangers so the outboard pad never moves and the inboard pad barely moves and when it does it stays there and drags and wears super fast so you need to replace pads/rotors/calipers again.
My ZX2SR came with no backing plate/dust shield on the front brakes. Had them on the rear. Maybe that is one reason I never had brake problems on track days.
OK, they stay! Thank you all. :-)
Just need to point out that many heavy trucks do not have them(mostly drums that I have seen), and I have never seen a street bike with them. Some dirt bikes come with a plastic cover but I raced hare scrambles for years and the brakes worked fine in all conditions. I would drag the brakes a bit coming out of water to heat them up and dry them out. And with regard to heat, how often do brakes in typical city highway service on a passenger vehicle heat up to a high degree? I would guess not too often.
Drum brakes have to have a backing plate to mount the hardware.
My Neon R/T's and Cobalt SS did not come with any. I do notice the Cobalt takes a beat for the brakes slow when wet.
You don't need them. The only thing they do is shield a bit of road dust and debris from reaching the disc pad interface. Remove them and your brake cooling will improve considerably while your inner pad will wear slightly faster.
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