Hi all,

Just installed new calipers ( O ring style) on my baby. What are your recommendations on which "Dot" type fluid should be used. Thanks in advance for your assistance with this.

DOT 4 is all you need.

If your car is stored for extended periods, or rarely driven, you might want to go with DOT 5, since it is silicon based, and doesn't absorb moisture. The two cannot be mixed, tho, so whatever choice you make, you will need to stick with, unless you want to go thru the hassle of completely flushing the system every time you switch from one to the other. Also, if you want to use DOT 5 now, you will have to completely flush the system of any/all DOT fluid that is still in it. 

DOT 4 is the way to go, in the long run....just don't let the car sit for long periods without driving, or at least pumping the pedal several times a month.

Joel Adams
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Another DOT 5 advantage besides not being hygroscopic is it won't hurt your paint.  It also has a higher boiling point which is important if the car is tracked.

1973 L-82 4 spd

What do  all the different DOT's mean🤔.Decided to go with Dot 5 synthetic brake fluid . Head to local store to purchase and discovered there are DOT 3, 4, 5, 5.1 and 4&5 which are all synthetic. Now I am totally baffled on which DOT to choose. 🤦‍♂️The brands were Prestone and Car Quest. Should I stay with the Chevrolet recommended DOT 3 and switch to synthetic DOT 3 or go with Dot 5 since I do not drive it a lot. Thanks for any clarification on this.

I think you can find the answer to your question here.

1973 L-82 4 spd

Dot 4 or 5.1.  🤷‍♂️

Decide to go with DOT 4 Silicone fluid. Since system needs to be flushed of the DOT 3 fluid is it necessary to change the rubber brake lines or just flushing them is ok?

THanks

Mistake... Meant to say  decided to go with DOT 5, not 4. Sorry.

I'm not a fan of silicone fluid, with new S/S O-Ring callipers, the supposed advantages of silicone somewhat mitigated as they are not so prone to the issues of little use, or rusty bores etc.  But that aside, it may be worth checking that your calliper manufacture doesn't have anything to say about silicone fluid.

I believe that one or two manufactures have disclaimers about using silicone fluids and discourage its use..

Please look at my answer to 74 Corvette calipers.

I read that and vouch for the difficulty in bleeding brakes with silicone - a friend of mine is always complaining that he cannot get the same firm pedal now he has silicone fluid.