vettejoel

Is ti O.K. to use Dot 5 brake fluid instead of Dot 3 in the clutch?...Thanks

mwittkopf

It is not recommended to use DOT 5 fluid because it is silicone based. DOT 4 fluid will work just fine and increase your boiling point by about 100 Deg. Motul and ATE SuperBlue are very popular ones. We have the Motul in stock if you are interested. It is used quite a bit in the high performance motorcycle market. Thanks!

Mike

SilvaDragon

There's actually a TSB that states that the clutch master
may squeak if the wrong fluid is used. GM has a specific
fluid they call out for the clutch. If the issue is noise,
you may want to look into bleeding out whatever is in
there.

CapeCodCoupe

Question.. should I change the clutch fluid? The previous owner put ATE Super Blue (it is blue!) in when he owned the car for one year. Now 5 years later.. clutch is fine but it is brake fluid..right? Absorbs moisture and should be changed? PM?

mwittkopf

Correct, it is just brake fluid and will absorb moisture. It is a PM item that a lot of people neglect. They change their brake fluid regularly, but do forget the clutch fluid even though it is the same thing. On a completely closed system, you shouldn't have to worry about moisture too much. As soon as the cap is opened though, it will take the moisture right out of the air.
Under hard racing conditions, it should be changed pretty regularly because of the heat in the clutch and slave cylinder. I've seen plenty of burnt (boiled) stock (DOT 3) fluid.

fmvette9

If you do not race, DOT5 is an excellent choice for the clutch. It is non-hydroscopic so it does not attract moisture, it is not harmful to paint, and the silicone lubes the seals. I put it in my C4 clutch 8 years ago, have not changed it since, it is still clean, and has never leaked. It can easily handle the heat of a non-race driven clutch. Brakes cause much more heat to the fluids. As an aside, Harley uses DOT5 as stock fill in their brakes. DOT3 should be changed every other year due to moisture. At the two year mark, I will change my C5 clutch fluid to DOT5.

see5

Cartek puts DOT 5 in their clutch/master package.

luvinc5

I thought DOT 5 will cause havoc with the seals and rubber in the brake hoses.

LoneStarFRC

I'm thinking this may be the case with a retrofit situation. Non-compatibility may be the reason, since despite all your efforts, you cannot get rid of all the old DOT3 (alcohol based) brake fluid. I bought GM hydraulic clutch fluid (don't have the part number with me right now) for when I bleed my clutch hydraulics. It contains other additives besides just being a brake fluid which are designed to help lubricate and preserve the seals in the system. HTH

Robert