Recommended Brake Fluid
Melting Slicks
Joined: May 2013
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From: Sacramento California
DOT5 has its own special formula and should never be mixed with any other spec.
Team Owner
Joined: Dec 1999
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From: Lacey WA RVN 68-69
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A DOT3 fluid is what the factory put in the C4 (and other generations). What sort of driving will you be doing? Just street use? Performance driving (autocross or track days)?
Using a DOT4 fluid provides a higher boiling point so it will withstand higher heat. I use ATE TYP200 in both my Corvettes. It's a DOT4 fluid and will handle heat from autocross and track days. There are a number of good DOT3 fluids; Castrol LMA, Valvoline SynPower and even the Ford
HD Mortorsports DOT3 fluid will work fine.
A DOT5 fluid should not be used as it's apparently not compatible with DOT3 or 4 fluid. But there are arguments as to whether or not this is true now for modern fluids.
If you haven't replaced the flex lines to the calipers, it would be a good time to do that when doing a fluid flush and refill
Using a DOT4 fluid provides a higher boiling point so it will withstand higher heat. I use ATE TYP200 in both my Corvettes. It's a DOT4 fluid and will handle heat from autocross and track days. There are a number of good DOT3 fluids; Castrol LMA, Valvoline SynPower and even the Ford
HD Mortorsports DOT3 fluid will work fine.A DOT5 fluid should not be used as it's apparently not compatible with DOT3 or 4 fluid. But there are arguments as to whether or not this is true now for modern fluids.
If you haven't replaced the flex lines to the calipers, it would be a good time to do that when doing a fluid flush and refill
Team Owner
Joined: Sep 2001
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From: Athens AL
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I generally go with Valvoline Synthetic DOT3 unless I am setting the car for autocrossing, in which case I may go with DOT4.
Melting Slicks
Joined: Jul 2005
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The big difference between DOT 3 & DOT 4 is the boiling points - both wet & dry. DOT 4 is compatible with DOT 3 fluid, and has higher wet and dry boiling points.
For a vehicle that is going to see Track use - I would not even think about NOT using DOT 4 fluid. I generally use ATE brake fluid on the stuff that is going to the track - which significantly exceeds the min DOT 4 specs, and is not hyper expensive.
If you are looking for cheaper DOT Fluid - Wal Mart typically has Prestone DOT 4 Brake Fluid for about $3.** a bottle.
There have been some posts about Valvoline DOT 4 not being very compatible with some seals - so you may want to do a search on that if you're planning to buy the Valvoline stuff.
Bottom line - while the DOT 4 fluid is slightly more expensive than the DOT 3 stuff - there is essentially no reason to use the DOT 3 over the DOT 4 stuff.
As for DOT 5 fluid - it's not hydroscopic - if you have a vintage car - that's driven hyper infrequently - maybe there is a reason to use it - but it's not compatible with the DOT 3 & DOT 4 stuff, and it's not as incompressible as the DOT 3 / DOT 4 stuff - so it's not recommended for ABS equipped cars.
For a vehicle that is going to see Track use - I would not even think about NOT using DOT 4 fluid. I generally use ATE brake fluid on the stuff that is going to the track - which significantly exceeds the min DOT 4 specs, and is not hyper expensive.
If you are looking for cheaper DOT Fluid - Wal Mart typically has Prestone DOT 4 Brake Fluid for about $3.** a bottle.
There have been some posts about Valvoline DOT 4 not being very compatible with some seals - so you may want to do a search on that if you're planning to buy the Valvoline stuff.
Bottom line - while the DOT 4 fluid is slightly more expensive than the DOT 3 stuff - there is essentially no reason to use the DOT 3 over the DOT 4 stuff.
As for DOT 5 fluid - it's not hydroscopic - if you have a vintage car - that's driven hyper infrequently - maybe there is a reason to use it - but it's not compatible with the DOT 3 & DOT 4 stuff, and it's not as incompressible as the DOT 3 / DOT 4 stuff - so it's not recommended for ABS equipped cars.
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Melting Slicks
Joined: Jan 2009
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From: folsom california
Dot 5 is too viscous to be used in brake systems with ABS; that said, it is an excellent choice for clutch hydraulics and older non ABS brake systems and has the added benefit of not harming paint, plus it's silicon base preserves neoprene or rubber brake seals.
Team Owner
Joined: Jul 2004
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From: Hartford WI
If the rubber hoses are old, leave it alone till you change the hoses to either new OEM ones or SS braided ones.
Last edited by aklim; Mar 23, 2018 at 10:18 PM.
Melting Slicks
Joined: Sep 2005
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From: merritt island fl
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DOT 5 is silicone based, and should not be mixed with conventional fluid.
Last edited by davekp78; Mar 24, 2018 at 01:59 PM.
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From: Hartford WI
Burning Brakes
Joined: Nov 2004
Posts: 1,193
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From: Hillsborough NC
I use the Motul 5.1 in my 78 and my 86. 5.1 is glycol-based and compatible with DOT 3 and 4, but not 5 (Silicone based).
Advantage of 5.1 is higher dry and wet boiling points than either DOT 3 or 4.
Type--Dry Boil Point--Wet Boil Point
DOT 3--205C/401F--140C/284F
DOT 4--230C/446F--155C/311F
DOT 5.1--270C/518F--190C/374F
5.1 is still hygroscopic, so it does still absorb moisture like DOT 3 and 4.
I've noticed no difference in braking and I don't track my cars. I just view the higher boiling points as insurance and safety margin.
My friends who do track their cars all use 5.1.
If you are changing, always a good idea to flush everything out. When I rebuilt brake system on my 86, I flushed the system first, then removed the calipers to replace the hoses and seals. Even though the fluid coming out of the bleeder was clear, the residue in the caliper from the old fluid/age was considerable.
Advantage of 5.1 is higher dry and wet boiling points than either DOT 3 or 4.
Type--Dry Boil Point--Wet Boil Point
DOT 3--205C/401F--140C/284F
DOT 4--230C/446F--155C/311F
DOT 5.1--270C/518F--190C/374F
5.1 is still hygroscopic, so it does still absorb moisture like DOT 3 and 4.
I've noticed no difference in braking and I don't track my cars. I just view the higher boiling points as insurance and safety margin.
My friends who do track their cars all use 5.1.
If you are changing, always a good idea to flush everything out. When I rebuilt brake system on my 86, I flushed the system first, then removed the calipers to replace the hoses and seals. Even though the fluid coming out of the bleeder was clear, the residue in the caliper from the old fluid/age was considerable.
Team Owner
Joined: Jul 2004
Posts: 28,431
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From: Hartford WI
I use the Motul 5.1 in my 78 and my 86. 5.1 is glycol-based and compatible with DOT 3 and 4, but not 5 (Silicone based).
Advantage of 5.1 is higher dry and wet boiling points than either DOT 3 or 4.
Type--Dry Boil Point--Wet Boil Point
DOT 3--205C/401F--140C/284F
DOT 4--230C/446F--155C/311F
DOT 5.1--270C/518F--190C/374F
5.1 is still hygroscopic, so it does still absorb moisture like DOT 3 and 4.
I've noticed no difference in braking and I don't track my cars. I just view the higher boiling points as insurance and safety margin.
My friends who do track their cars all use 5.1.
If you are changing, always a good idea to flush everything out. When I rebuilt brake system on my 86, I flushed the system first, then removed the calipers to replace the hoses and seals. Even though the fluid coming out of the bleeder was clear, the residue in the caliper from the old fluid/age was considerable.
Advantage of 5.1 is higher dry and wet boiling points than either DOT 3 or 4.
Type--Dry Boil Point--Wet Boil Point
DOT 3--205C/401F--140C/284F
DOT 4--230C/446F--155C/311F
DOT 5.1--270C/518F--190C/374F
5.1 is still hygroscopic, so it does still absorb moisture like DOT 3 and 4.
I've noticed no difference in braking and I don't track my cars. I just view the higher boiling points as insurance and safety margin.
My friends who do track their cars all use 5.1.
If you are changing, always a good idea to flush everything out. When I rebuilt brake system on my 86, I flushed the system first, then removed the calipers to replace the hoses and seals. Even though the fluid coming out of the bleeder was clear, the residue in the caliper from the old fluid/age was considerable.
Le Mans Master
Joined: Oct 2007
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From: Akron Ohio
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I use AMSOIL Racing DOT4 in my race car. IT has a 580°F dry and 410°F wet boiling point which exceeds the DOT5.1 shown above. Lots and lots of repeated high speed stops and I have never boiled the fluid on track.
https://www.amsoil.com/shop/by-produ...-EA?zo=1934716
But for a street car any good DOT3/4 fluid will be sufficient.
https://www.amsoil.com/shop/by-produ...-EA?zo=1934716
https://www.amsoil.com/shop/by-produ...-EA?zo=1934716
But for a street car any good DOT3/4 fluid will be sufficient.
https://www.amsoil.com/shop/by-produ...-EA?zo=1934716
Last edited by Kubs; Mar 29, 2018 at 11:30 AM.