Help - brake fluid ??
Thread Starter
Race Director
Joined: Dec 2006
Posts: 13,178
Likes: 99
From: West Chester OH
2020 C6 of the Year Finalist - Unmodified
Cruise-In IX Veteran
St. Jude Donor '08 thru '13
Help - brake fluid ??
I don't know what kind of brake fluid is in my '68, I need to add and don't want to mess up.
The fluid that is in it is clear but doesn't seem to have the typical brake fluid smell.
I have some Castrol LMA and also some DOT 5 fluid, the Castrol is clear and smells, the DOT 5 has a purplish tinge and no smell.
Anyway to tell what it is? A search didn't come up with a definite answer.
Thanks!
The fluid that is in it is clear but doesn't seem to have the typical brake fluid smell.
I have some Castrol LMA and also some DOT 5 fluid, the Castrol is clear and smells, the DOT 5 has a purplish tinge and no smell.
Anyway to tell what it is? A search didn't come up with a definite answer.
Thanks!
Melting Slicks
Joined: Mar 2007
Posts: 2,100
Likes: 12
From: Frederick Maryland
Do not under any circumstances mix DOT 5 with DOT 3 or 4 mineral based brake fluid. It will make a cloudy mess and give you a very mushy pedal.
It sounds like you have DOT 3 or 4 in it now. If you're not sure what you have...have your brake system completely flushed and dried before adding whatever fluid you want to keep in it.
Your car would have originally come with DOT 3. I would stick with that. The only way I would change to DOT 5 synthetic would be if the entire brake system...metal and rubber lines, seals, etc., were all replaced. Synthetic has its advantages, especially in a car not regularly driven, but it can create problems if not careful in using it.
It sounds like you have DOT 3 or 4 in it now. If you're not sure what you have...have your brake system completely flushed and dried before adding whatever fluid you want to keep in it.
Your car would have originally come with DOT 3. I would stick with that. The only way I would change to DOT 5 synthetic would be if the entire brake system...metal and rubber lines, seals, etc., were all replaced. Synthetic has its advantages, especially in a car not regularly driven, but it can create problems if not careful in using it.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Rub some fluid between your fingers-the dot5 will feel slicker than regular fluid.Probably not recomended but I touch it to the tip of my tongue-reg. is bitter --synthetic is almost tasteless---spit spit spit
Melting Slicks
Joined: May 2005
Posts: 2,209
Likes: 12
From: Montgomery Alabama
Cruise-In VII Veteran
St. Jude Donor '06
I usually flush my brake systems with DOT4 fluid. I usually flush with clear DOT4, then fill with ATE Super Blue. It is real easy to tell when it is done.
Melting Slicks
Joined: Jan 2003
Posts: 2,817
Likes: 21
From: Somerset, NJ
Get a clean empty bottle the size of a Baby food bottle or what ever small size bottle you can find. Open up your master cylinder and take some fluid out to fill the baby bottle a quarter of the way up. Now take some water of the same amount and put it in the same bottle with your brake fluid. Put the cap on the bottle. Shake it up and come back later on to view it. Say maybe an hour. If the brake fluid stays mixed with the water you have Dot 3 brake fluid in your master cylinder. If the brake fluid floats on top of the water you have Dot 5 Silicone brake fluid in your master cylinder.
Racer
Joined: Aug 2005
Posts: 435
Likes: 2
From: Boise Idaho
Gotta love the old school method for testing auto fluids.
I wonder how they effect my cholestorol levels.
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Burning Brakes
Joined: Jun 2004
Posts: 872
Likes: 3
From: Cortlandt Manor New York
Get a clean empty bottle the size of a Baby food bottle or what ever small size bottle you can find. Open up your master cylinder and take some fluid out to fill the baby bottle a quarter of the way up. Now take some water of the same amount and put it in the same bottle with your brake fluid. Put the cap on the bottle. Shake it up and come back later on to view it. Say maybe an hour. If the brake fluid stays mixed with the water you have Dot 3 brake fluid in your master cylinder. If the brake fluid floats on top of the water you have Dot 5 Silicone brake fluid in your master cylinder.
