Wheel Rim Dust Shields: More Trouble Than They're Worth? - Page 2 - PeachParts Mercedes-Benz Forum

vstech · #16 04-09-2011, 06:14 PM

... you could buy an additional set of shields, and put them on all 4 wheels, or remove them from the fronts...
I don't rotate tires... if the fronts are wearing unevenly, I get an alignment.

compress ignite · #17 04-09-2011, 07:01 PM

Take them Off. (Waste Management comes by every week!)

'Want less Brake Dust and Cleaner Wheels?
1.Akebono (Ceramic Pads)
2.http://www.poorboysworld.com/wheel-sealant.htm

brakeengr · #18 04-09-2011, 08:04 PM

Quote:

Originally Posted by compress ignite

Take them Off. (Waste Management comes by every week!)

X2
I got rid of them from my W124. The W123 never had them.
Bad for air flow; and I think wheels actually look better when you can see the rotor and caliper. Just need to do a little more brake dust cleaning!

babymog · #19 04-11-2011, 09:02 AM

Get rid of them, not Mercedes parts nor designed with/by Mercedes Engineers.

Paint the caliper a nice silver or black, and look at it instead.

JB3 · #20 04-11-2011, 12:32 PM

IMO, air flow loss for cooling the brakes that could be affected by these shields is negligible. Id leave them on personally for cleanliness. There is abundant flow behind the wheel under the car if you are worried about it, but think about what you guys are saying,

I doubt the brakes really require a certain amount of air flow over them for cooling properly, they should work just as well with now air flow as with tons.
Heavy truck dually brake setups are almost completely covered by solid steel wheels, where adequate braking and heat shedding is a far more important consideration, yet there are often no or few holes in the wheel itself. If proper braking heat loss really depended on outside the wheel air flow, these cars would all have been designed with very special air scooping rims, not bundts and steels.
We are worrying about a non issue here.

MB Steel wheels and hubcaps are almost a solid surface also, but we're not worried about those

babymog · #21 04-11-2011, 01:15 PM

I kind of agree with you drop, if not completely.

When these cars were new, I remember these and believe that they were sold as "Kleen Wheels" or something like that. They had little turbine-like vents stamped near the outer edge and marketed them as being compatible and maintaining adequate airflow over brakes.

Although brakes and wheels have evolved to create more airflow for cooling, the 123 diesel probably has more than enough cooling for its brakes in normal use, even with dust shields.

Personally I just don't care for the looks of these shields, but in bundts or the 15-hole flat-face wheels of the '80s, you can't see the shields, just the dust (and bundts look like a pain to clean). In a later more open wheel, I'd do without for sure though.

Orv · #22 04-11-2011, 01:26 PM

Quote:

Originally Posted by dropnosky

I doubt the brakes really require a certain amount of air flow over them for cooling properly, they should work just as well with now air flow as with tons.

I think you're right for typical driving. It might be different if you drive very aggressively, travel in mountainous areas, or tow a trailer. I've actually seen someone in a pickup lose brakes on a long downgrade while towing, due to boiling the brake fluid.

Quote:

Heavy truck dually brake setups are almost completely covered by solid steel wheels, where adequate braking and heat shedding is a far more important consideration, yet there are often no or few holes in the wheel itself.

Trucks are also using drum brakes, so additional airflow isn't going to help much. I've frequently seen truck brakes literally smoking hot after just a freeway panic stop. The strategy for trucks seems to be to use extremely large, heavy drums and rely on thermal mass. For long downgrades they depend heavily on engine braking to supplement the wheel brakes. Perhaps not coincidentally, runaway truck ramps are a common feature of mountainous stretches of highway.

brakeengr · #23 04-11-2011, 01:30 PM

Maybe in a normal stop, regular speed you may not feel the effect of air flow or no air flow. But when you need to make consecutive stops from say 60 mph, air flow is definitely a factor.
No air flow ==> higher pad temp ===> fade. Not only does the pad not cool down, but the rotor retains more heat also, and this affects the pad material. Done enough dynamometer tests to quantify this effect!!
As for comparing it to trucks and heavy vehicles, remember they are completely different brake systems and different materials- they were designed to work in that environment. Their surface area is more, unit pressure on the linings is less, thermal characteristics of the material is different, etc. etc. etc...
These pads in the calipers are relatively quite small, and do a lot of work!

vstech · #24 04-11-2011, 01:35 PM

Quote:

Originally Posted by Orv

I think you're right for typical driving. It might be different if you drive very aggressively, travel in mountainous areas, or tow a trailer. I've actually seen someone in a pickup lose brakes on a long downgrade while towing, due to boiling the brake fluid.

I've seen plenty of improperly loaded trailers without brakes cause the tow vehicle to loose braking due to boiling... don't do that again! also if you travel in the mountains, you MUST learn to drive within the ability of the vehicle's brakes. if your vehicle cannot brake adequately on downhill runs, ENGINE braking must be used effectively!

Quote:

Originally Posted by Orv

Trucks are also using drum brakes, so additional airflow isn't going to help much. I've frequently seen truck brakes literally smoking hot after just a freeway panic stop. The strategy for trucks seems to be to use extremely large, heavy drums and rely on thermal mass. For long downgrades they depend heavily on engine braking to supplement the wheel brakes. Perhaps not coincidentally, runaway truck ramps are a common feature of mountainous stretches of highway.

Totally true! seasoned truckers KNOW how to balance the speed and load with lower gears and engine / jake braking. NO TRUCK loaded is able to handle extended braking down steep grades. engine/jake braking is the only serious way.
BUT!!! keep this in mind also... there is NO fluid in truck brakes to boil! it's pneumatic. the Drums DO INDEED melt/fail as do the shoes wear beyond limits and fail!

Orv · #25 04-11-2011, 01:41 PM

Quote:

Originally Posted by vstech

I've seen plenty of improperly loaded trailers without brakes cause the tow vehicle to loose braking due to boiling... don't do that again! also if you travel in the mountains, you MUST learn to drive within the ability of the vehicle's brakes. if your vehicle cannot brake adequately on downhill runs, ENGINE braking must be used effectively!

Yup...once you've experienced brake fade on a downhill slope you're overcome with a strong desire to never experience it again.

vstech · #26 04-11-2011, 01:50 PM

Quote:

Originally Posted by Orv

Yup...once you've experienced brake fade on a downhill slope you're overcome with a strong desire to never experience it again.

ya wanna REALLY experience terror... get a trailer and load ALL the heavy stuff at the very back of the trailer... then go DOWN the rocky mountains! as a 16 year old boy with your brand new drivers license...

that boy was me

lets just say, I ALWAYS load a trailer correctly and VERIFY it is loaded and attached the way I want it.

vstech · #27 04-11-2011, 01:51 PM

Quote:

Originally Posted by vstech

ya wanna REALLY experience terror... get a trailer and load ALL the heavy stuff at the very back of the trailer... then go DOWN the rocky mountains! as a 16 year old boy with your brand new drivers license...

that boy was me

lets just say, I ALWAYS load a trailer correctly and VERIFY it is loaded and attached the way I want it.

lets ALSO say it's impressive how FAST you can drive DOWN a 7% grade in a van with a trailer bouncing behind you...

I crested the top of the mountain at 60 I think... the 1984 manual transmission van Speedo only went to 85... I think I bent the needle on the peg...

Stretch · #28 04-11-2011, 02:24 PM

Quote:

Originally Posted by vstech

...I think I bent the needle on the peg...

Ha ha - the old "I think I bent the needle on the peg" officer - now I can't tell how fast I'm driving!

JB3 · #29 04-11-2011, 02:52 PM

Quote:

Originally Posted by Orv

Trucks are also using drum brakes, so additional airflow isn't going to help much. I've frequently seen truck brakes literally smoking hot after just a freeway panic stop. The strategy for trucks seems to be to use extremely large, heavy drums and rely on thermal mass. For long downgrades they depend heavily on engine braking to supplement the wheel brakes. Perhaps not coincidentally, runaway truck ramps are a common feature of mountainous stretches of highway.

Let me clarify, im talking about NPR's, P-vans, that kind of stuff, about the size of a UPS truck vs a tractor trailer rig. In those applications, most are using front and rear disc brakes completely shielded by the wheel

vstech · #30 04-11-2011, 02:56 PM

Quote:

Originally Posted by dropnosky

Let me clarify, im talking about NPR's, P-vans, that kind of stuff, about the size of a UPS truck vs a tractor trailer rig. In those applications, most are using front and rear disc brakes completely shielded by the wheel

I don't think I've ever seen an enclosed wheel on a panel van/truck... dually vehicles have to have hand sized holes in the wheels for the air chuck to pass through...