W123 Brake Upgrade. - PeachParts Mercedes-Benz Forum

winmutt · #1 10-25-2006, 11:12 AM

Since I have gone with larger and wider rims my braking has been seriously hampered. I've decided to go ahead and install W126 calipers and rotors and I understand that any of the later model (83+?) W126's should go right on. Anyone have any experience in this? I have done a fair amount of reading on here and it seems that its just a bolt on operation?

vstech · #2 10-25-2006, 11:17 AM

are they differant?
I have worked on both vehicles, and I thought they were almost the same calipers/rotors/Mastercyllinder... the pads swap between.

winmutt · #3 10-25-2006, 11:35 AM

Quote:

Originally Posted by vstech

are they differant?
I have worked on both vehicles, and I thought they were almost the same calipers/rotors/Mastercyllinder... the pads swap between.

300SD has slotted and in '85 then went to 300mm from ~280mm. According to what I have read its a bolt on swap.

Kjell · #4 10-25-2006, 11:36 AM

On cars in europe, the difference between 123 and 126 (126 up to -86) is that the 126 has ventilated discs. Diameter is the same. The only diffence on the caliper is a spacer i the middle of it.

/ Kjell

vstech · #5 10-25-2006, 11:40 AM

Cool! I will take a closer look at my SD's

rwthomas1 · #6 10-25-2006, 10:38 PM

Please explain to me why a change in tire size/wheel size would change braking ability? Unless you significantly increase the overall diameter of the wheel/tire package then there should be no change at all. In fact, usually increasing the contact patch through larger tires improves braking. RT

vstech · #7 10-25-2006, 10:55 PM

a guess would be he did increase overall diamater. also, while larger contact patch would inprove the vehicle's 100-0 distance, it will place a larger amount of heat into the rotor. many stops would effectively lower the braking ability of the car.
I doubt the excellent brakes of MB would be adversly affected though.
John

my123ca · #8 10-25-2006, 10:58 PM

I used the caliper and rotor of the '83SD on my '85D. Ive heard that the vented rotors of the SD last longer and dont warp as much. The orig. rotors on the 300d would always warp. Ive changed it 4X already since '88. You have to change both caliper and rotor and its just PnPlay. There is a slight increase in stopping power. I want to try the zimmerman next on the rear of the 123.

Ara T. · #9 10-25-2006, 10:59 PM

Larger and wider rims = more unsprung weight = less effective braking. The way to do it is to find wider, lighter rims/tires.

And the W126 has ventilated rotors which I doubt would really shorten your stopping distances, it would stop them from fading though. You have to be pretty tough on the brakes to get fade though.

winmutt · #10 10-26-2006, 09:17 AM

Quote:

Originally Posted by Ara T.

Larger and wider rims = more unsprung weight = less effective braking. The way to do it is to find wider, lighter rims/tires.

And the W126 has ventilated rotors which I doubt would really shorten your stopping distances, it would stop them from fading though. You have to be pretty tough on the brakes to get fade though.

The POs mechanic had set the length of the push rod a bit to far so I always have a fair bit of grabbing and get fade pretty quick. I figured since I was going to have to bleed the brakes completely to adjust the push rod so why not spend the extra $36 at pull a part and get some extra stopping power for the mouintains

Sprung or unsprung has nothing to with it. Its centripedal force and alot more friction .

riethoven · #11 10-26-2006, 10:28 AM

Quote:

Originally Posted by Ara T.

Larger and wider rims = more unsprung weight = less effective braking. The way to do it is to find wider, lighter rims/tires.

And the W126 has ventilated rotors which I doubt would really shorten your stopping distances, it would stop them from fading though. You have to be pretty tough on the brakes to get fade though.

Reducing fade is reducing heat which leads to shorter stopping distances in a panic stop. That is what matters the most, not typical stopping.

rudolfgreen · #12 10-26-2006, 10:35 AM

haven't noticed any decrease in stopping power with the 17"s,
but am always interested in increased performance mods..

winmutt · #13 10-26-2006, 10:51 AM

Quote:

Originally Posted by riethoven

Reducing fade is reducing heat which leads to shorter stopping distances in a panic stop. That is what matters the most, not typical stopping.

Which is precisely my complaint. Normal stopping is "OK" a bit softer but ok for general driving.

t walgamuth · #14 10-26-2006, 11:49 PM

more unsprung weight will result in less grip on a bumpy surface and hence poorer braking results.

the biggest advantage in my mind is the reduced warping of the rotors. i too could not keep rotors on my 82 wagon.

tom w

SpecialDelivery · #15 02-04-2013, 08:04 PM

ok so I have a leaky caliper in my 300D, passenger rear. I went to the yard today to find a 2nd gen W126... got the calipers and ONE of the rotors off...they're rusted on pretty good. How do we get the dust shield off? do we have to tear down the entire hub/ebrake assembly?

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode