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brakes: DOT 3 or DOT 4?

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NutmegCT

NutmegCT

Great Pumpkin
Bronze
Offline
I think a flush and fill might be due in Rolling Wreck. Agree?

View attachment 25183

Fresh fluid on the left; a sample of mine on the right.

My neighbor (long-time mechanic) asked me why I was thinking of using DOT 4 instead of DOT 3.

Your reply to him ...?
 
DOT4 has a higher resistance to temperature and even when it absorbs a bit of moisture will still be more resistant to fade than the DOT3. Other than that, they are the same basic chemistry. Since the 190b has drum brakes up front, I would use the DOT4 to get that extra bit of resistance to fade since the drums tend to retain heat far more than disks. It won't make any difference in "normal" driving but if you go down a mountain it could be very important if you want to stop at the bottom.
 
70herald said:
... Since the 190b has drum brakes up front, I would use the DOT4 to get that extra bit of resistance to fade since the drums tend to retain heat far more than disks.
Click to expand...

YOU KNOW THE 190b! Fantastic. Glad to know someone else here who's familiar with this wonderful old car.

And thanks for the DOT4 reinforcement. I hadn't realized there was more "fade resistance" due to higher temp tolerance.

Stopping at the bottom of a mountain is pretty easy - but stopping halfway down the mountain might be more important!

Thanks.
Tom
 
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