Front disks... how important are disk brake dust shields?

[steveh326]

rotor dust or splash shields... got one that is completely rusted away... the other is salvageble, but both could use replaced. How important are they in the grand scheme of things? one person said they helped maintain braking performance in the rain, but I dunno... it's about $80 I could use elsewhere on the car if they are optional.

 

[AzPete]

They do keep a lot of trash from splashing in the disc. Water will clear and dry pretty fast but I would wonder about all the sand that also travels with that water. Doubt it all gets washed off looking at other undercarriage parts. They would also prevent any rocks from bouncing up and putting a nick in the disc or possibly wedging in the pad/disc area. Not sure if they aid cooling much but they might based on how the turbulence created by the spinning wheel flows.

Now, how much of a chance of any of this happening.......no idea.

 

[lethal289]

i've driven about 8k miles in my pickup with no front dust shields and not one problem. i've heard some say that it promotes cooling without them, and some say they help deflect air into the brakes so i assume its a wash there.

 

[Starfury]

If you think about it, every car manufacturer puts these on every car. Do you think they would spend all that money if it wasn't important?

 

[steveh326]

If you think about it, every car manufacturer puts these on every car. Do you think they would spend all that money if it wasn't important?

yeah, I was thinking about that very thing last night, and decided to bite the bullet and get them. funny thing is tho is that motorcycle mfg's don't do them... I've riddin motorcycles all my life and all of the bikes have disks front/rear and no dust shields. But I guess you can't really compare a 700-800lb motorcycle to a 2,500? pound car.

also strange, I checked out some aftermarket disk brake kits like SSBC and Wilwood, I didn't see dust shields with their kits although they may be included and just not shown in the pics I looked at.

 

[apollard]

I know lots of cars that are not running them with no ill effects. As you said, aftermarket kits tend to not have them, and nobody reports issues that I've read.

It's possible the shields are a regulatory hangover from a time when they were necessary for performance (older materials that degraded significantly when wet, etc), and are not needed today. Lots of those on the books - like the DOT approved headlight pattern, which sucks and is no longer necessary with new projector technology.

 

[Horseplay]

If you think about it, every car manufacturer puts these on every car. Do you think they would spend all that money if it wasn't important?

You might also want to consider that almost all vehicles are built in a "one size fits all" style. It could be that manufacturers feel the shields are necessary in certain climates or under certain driving conditions that maybe not all vehicles may experience.

I also don't think "all that money" is applicable here. A typical shield is nothing more than a very cheap metal stamping and a couple blots/screws to hold it in place.

My Wilwood kits did not include any type of shields for front or back, FWIW.

 

[Midlife]

I wonder if the dust shields are more like "ice and snow" shields. For a motorcycle, anyone crazy enough to be out driving in ice and snow wouldn't need them anyway for very long...

 

[AzPete]

Maybe we are thinking the wrong direction.....they keep the brake dust off the rest of the car undercarriage......

 

[steveh326]

Maybe we are thinking the wrong direction.....they keep the brake dust off the rest of the car undercarriage......

hmmmmm... you may be on to something there...

 

[Starfury]

I also don't think "all that money" is applicable here. A typical shield is nothing more than a very cheap metal stamping and a couple blots/screws to hold it in place.

How much do you think that costs? Say $10 per vehicle. Multiply that by how many cars are churned out each year. You think vehicle manufacturers don't do that math?

I do agree, though, it may have something to do with adverse weather conditions.

 

[RapidRabbit]

I don't have them on my car. Haven't noticed any problems.

Sent from my Desire HD using Tapatalk

 

[Horseplay]

How much do you think that costs? Say $10 per vehicle. Multiply that by how many cars are churned out each year. You think vehicle manufacturers don't do that math?

I do agree, though, it may have something to do with adverse weather conditions.

I'd say you're more than double with your cost guess but my real point was it would be less expensive to put them on all cars than go without and deal with warranty costs on cars sold in areas where they might be beneficial. That is the real math (and yes, they most certainly crunch the numbers all ways on all things). Cheaper to include originally or cheaper to roll the dice on repair costs later.

 

[buening]

http://www.freepatentsonline.com/4005768.html

Due to the environment in which a disc brake operates, care must be taken to protect the brake components from dirt to the greatest extend that is reasonably possible. In view of the problem presented, the dust shield is designed to prevent road water from being splashed upon the braking surfaces of the rotor and to prevent dust particles carried by air from impinging upon the braking surfaces. These contaminants can cause excessive and uneven wear of the braking surfaces of the rotor and of the brake linings during repeated brake applications.

A dust shield for a disc brake according to this disclosure is characterized by its superior performance and its economical manufacture. The dust shield, although of relatively simple construction, effectively reduces the amount of road water that may be splashed against the brake rotor. In addition, dust particles carried by the air are, to a large extent, excluded from the air flowing through the ventilation holes and over the surfaces of the brake rotor

 

[Chris Kennedy]

They are very important if you drive your car in wet weather conditions. Often called "water shields" as well, if you encounter heavy rain they tend to keep some of the water away from the discs, which both helps the brakes bite quicker AND avoid pulling to one side during the first few seconds after you apply the brakes. I think it's negligent of a number of the aftermarket brake suppliers not to automatically include these with their kits.

/s/ Chris Kennedy

 

[Dennis Harrelson]

FWIW, the taxi/cop car Crown Vic rear discs I used didn't have any shields. Of course, rear brakes provide only about 25% of the stopping power, so...