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View Full Version : why are there "dust" shields on front rotors?



trfourtune
07-10-2009, 11:32 AM
Stupid question but why are there "dust" shields on front rotors? The don't seem to have any purpose. They don't scoop in cold air on a tr4. Brake dust is sucked out through the wheel due to a lower pressure area there. Seems like i don't need or want them (plan to run a big air hose to the bearings anyways which will feed my vented rotors anyways-no shield).
Rob

TR4nut
07-10-2009, 11:45 AM
I always assumed they were meant to protect the rotor if something nasty flipped up off the roadway. Worst case, get a small rock to slide in between the rotor and caliper for example. Not sure if they do much else.

trfourtune
07-10-2009, 11:53 AM
I think most things that "flip up" from the road tend to be behind the tire foot print. I think that they might keep grease from over exuberant sloppy maintenance from getting on the rotor, but i can't think of a really good reason. If anything, i would think that they restrict air flow from cooling the rotor.
R

martx-5
07-10-2009, 11:57 AM
The early disc braked TR3s &amp; 3As didn't had the dust sheild. I think they were added to keep excess <span style="font-weight: bold">water</span> off the rotor.

TR6oldtimer
07-10-2009, 01:41 PM
Union negotiated make work.

tomshobby
07-10-2009, 01:42 PM
The early disc braked TR3s &amp; 3As didn't had the dust sheild. I think they were added to keep excess <span style="font-weight: bold">water</span> off the rotor.

I think Art is right.

They also keep small animals from getting caught in there! :jester:

tomgt6
07-10-2009, 03:30 PM
Like most English cars, or at least mine, they tend to leave oil and grease everywhere. Have you ever seen a rusted triumph block, most likely not in a running car. Why, because they like to leave oil everywhere.

Well, if your brakes squeak then you can always oil them. And if the shield isn't there you will tend to get more oil and grime on them. I can say oiled brakes don't do much for stopping.

So my thought is they are there to help keep the grime off.

Don Elliott
07-10-2009, 06:03 PM
My 1958 TR3A (TS 27489 LO) never had dust sheilds on the front rotors since I bought my TR brand new. I never missed them. My brakes work fine without them. The late TR3A I restored (TS 81551 L) had them so after I cleaned them up, I put them back on in case the car ever finds itself being judged at a TRA or VTR concours meet.