Brake Fluid specifications
Thread Starter
Drifting
Joined: Mar 2010
Posts: 1,901
Likes: 361
From: TX
Brake Fluid specifications
I'm getting ready to change the brake fluid in my car and looking through the service manual they seem pretty adamant about using DOT 3 Delco Supreme 11 (GM p/n 12377967 fluid), though they do say "or equivalent".
So just what does "or equivalent" mean? Most of the brake fluid I find says it meets or exceeds both DOT 3 and DOT 4 specs. The fluid I normal use in my other vehicles is Castrol GTLMA DOT 3/4 (synthetic).
I'm wondering if there is any reason normal off the shelf DOT 3/4 fluid would cause any problems. I know that the silicone based DOT 5 stuff can cause problems, but I've never seen any warning against DOT 4 fluid.
Anyone ever used DOT 4 brake fluid in their car? It seems to be a superior fluid to DOT 3. Thoughts, comments?
So just what does "or equivalent" mean? Most of the brake fluid I find says it meets or exceeds both DOT 3 and DOT 4 specs. The fluid I normal use in my other vehicles is Castrol GTLMA DOT 3/4 (synthetic).
I'm wondering if there is any reason normal off the shelf DOT 3/4 fluid would cause any problems. I know that the silicone based DOT 5 stuff can cause problems, but I've never seen any warning against DOT 4 fluid.
Anyone ever used DOT 4 brake fluid in their car? It seems to be a superior fluid to DOT 3. Thoughts, comments?
Team Owner
Joined: Sep 2005
Posts: 20,352
Likes: 568
From: Ventura County, Calif
Good discussion and info in here but ignore the 1st post: 
http://forums.corvetteforum.com/c6-c...yesterday.html
http://forums.corvetteforum.com/c6-c...yesterday.html
Race Director
Joined: Sep 2000
Posts: 11,139
Likes: 1,910
From: Missouri City, TX
DOT 4 is completely compatible with DOT 3 meaning that they can be mixed together. Since the hydraulic clutch uses DOT 4, is more convenient for myself to stock just DOT 4 and use it in both brake and clutch master cylinders. IMHO
Team Owner
Joined: Sep 2000
Posts: 25,001
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From: Far NW 'burbs of Chicago
St. Jude Donor '13
When I had the dealership flush my brakes last year, I had them use the GM DOT 4. Works fine, so should any other DOT4.
