brake fluid compatibility
Thread Starter
Safety Car
Joined: May 2005
Posts: 4,176
Likes: 7
From: Jennings LA
brake fluid compatibility
will Valvoline Synpower-Synthetic Brake Fluid mix with dot 3 flluid? I am doing the C5 upgrade and it is recomended by many. if not how would you flush the system. I have dot 5 in my '71 and you definitley can't mix it with dot 3.
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
Several years ago, when I re-did my brakes, the first time, I purchased four speedbleeders (www.speedbleeder.com) and used Valvoline synthetic (a quart) and filled up the master cylinder five or six times untill the M/C was clear as water.
With "Speedbleeders", the bleed/flush is a snap.
With "Speedbleeders", the bleed/flush is a snap.
Last edited by runner140*; Jan 10, 2007 at 12:42 PM. Reason: corrected web site
Race Director
Joined: Dec 2006
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DOT 5 is a different animal altogether. If I were switching to DOT 5, I would probably use air to blow out the lines followed by an alcohol rinse and more air. And the cylendars, I would have to figure some way to make sure there was no left over old fluid without getting anything on a seal that would harm it. DOT 5 is also rumored to produce and suspend little bubbles in cars that have ABS.
DOT 3, 4, and 5.1 are hygroscopic while DOT 5 is not. Ask in the C3 forum and I be a lot of the guys there are using DOT 5 to ward off rust.
In a pinch I would top off with DOT 4 in a DOT 3 system. I think the bottles even say it's ok to mix 4 to 3. The Castrol in my garage simply says "exceeds DOT 3 and DOT 4..."
Racer
Joined: Aug 2002
Posts: 386
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From: Lancaster Lancashire
I wouldn't mix fluids of differing types. However, I would replace DOT 3 with DOT 4 or DOT 5.1 in any car without vigorously cleaning out the lines. I would simply use the new to push out the old.
DOT 5 is a different animal altogether. If I were switching to DOT 5, I would probably use air to blow out the lines followed by an alcohol rinse and more air. And the cylendars, I would have to figure some way to make sure there was no left over old fluid without getting anything on a seal that would harm it. DOT 5 is also rumored to produce and suspend little bubbles in cars that have ABS.
DOT 3, 4, and 5.1 are hygroscopic while DOT 5 is not. Ask in the C3 forum and I be a lot of the guys there are using DOT 5 to ward off rust.
In a pinch I would top off with DOT 4 in a DOT 3 system. I think the bottles even say it's ok to mix 4 to 3. The Castrol in my garage simply says "exceeds DOT 3 and DOT 4..."
DOT 5 is a different animal altogether. If I were switching to DOT 5, I would probably use air to blow out the lines followed by an alcohol rinse and more air. And the cylendars, I would have to figure some way to make sure there was no left over old fluid without getting anything on a seal that would harm it. DOT 5 is also rumored to produce and suspend little bubbles in cars that have ABS.
DOT 3, 4, and 5.1 are hygroscopic while DOT 5 is not. Ask in the C3 forum and I be a lot of the guys there are using DOT 5 to ward off rust.
In a pinch I would top off with DOT 4 in a DOT 3 system. I think the bottles even say it's ok to mix 4 to 3. The Castrol in my garage simply says "exceeds DOT 3 and DOT 4..."
All the above is good advice.
DOT 3, DOT 4 & DOT 5.1 are compatible with each other and the ABS system. DOT5 is not compatible with any of the above.
Race Director
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
Race Director
Joined: Jul 2004
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From: Lake Havasu City, AZ
DOT 3 fluids are esters
DOT4 fluids are borated esters. this gives them higher boling points and less tendency to absrb water.
DOT 4 can be added to DOT 3.
Specifically I have used Valvoline Synpower DOT 3 and DOT 4 for 3 years in my '88 and for 15k miles in my '01 without any issues.
I am also a big speedbleeders fan
http://www.speedbleeder.com/
DOT4 fluids are borated esters. this gives them higher boling points and less tendency to absrb water.
DOT 4 can be added to DOT 3.
Specifically I have used Valvoline Synpower DOT 3 and DOT 4 for 3 years in my '88 and for 15k miles in my '01 without any issues.
I am also a big speedbleeders fan
http://www.speedbleeder.com/
Burning Brakes
Joined: Sep 2004
Posts: 1,181
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From: Manchester NH
I use the Valvoline SynPower and like it a lot. It should mix with DOT 3 but for the price you're better off buying 3 quarts and doing a full flush to maximize performance of the upgrade.
Speedbleeders are OK but a Motive bleeder is even better! Pump up the Motive, crack the bleeder screw and just watch to make sure the m/c isn't emptied.
http://www.motiveproducts.com/02bleeders.html
Speedbleeders are OK but a Motive bleeder is even better! Pump up the Motive, crack the bleeder screw and just watch to make sure the m/c isn't emptied.
http://www.motiveproducts.com/02bleeders.html
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
ISpeedbleeders are OK but a Motive bleeder is even better! Pump up the Motive, crack the bleeder screw and just watch to make sure the m/c isn't emptied.
http://www.motiveproducts.com/02bleeders.html
http://www.motiveproducts.com/02bleeders.html
I made my own power bleeder this last summer, but if I'd known about the Motive unit for only $55, I wouldn't have gone to all the trouble of fabbing one.
Thanks for the link!
Larry
code5coupe
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When I had a Saab there was a common trick discussed in alt.autos.saab. On those cars the clutch fluid was fed off the brake reservoir. So to bleed the slave we would buy a new cap for the reservoir and drill a small hole in it just a bit too small to fit a football needle into. Then we'd force a needle in and pump it up with any bycycle pump and open the bleed valve.
Burning Brakes
Joined: Sep 2004
Posts: 1,181
Likes: 1
From: Manchester NH
The nice thing about the Valvoline fluid is that it's compatible with both DOT 3 & 4 but has a higher wet boiling point than either 3 or 4 (if I recall correctly). And is not nearly as expensive as the higher end Motul type brands.
I flush and bleed often as I a/x and track the car and work on the theory that fresh lower grade fluid is better than older higher grade fluid.
I flush and bleed often as I a/x and track the car and work on the theory that fresh lower grade fluid is better than older higher grade fluid.
