Brake Fluid for classic

phil_10, Aug 31, 8:03am
What fluid to use dot3 or dot4 have original brake setup, car is 70 xy falcon


pebbles61, Aug 31, 8:05am
No Haynes book of lies!

murray55, Aug 31, 8:10am
I would go for dot4 it is less likely to absorb moisture

pebbles61, Aug 31, 8:14am
I use DOT4 in my 1970 car

unclejake, Aug 31, 8:27am
DOT4 will be perfectly fine.

If it is a minter and you are scared of paint damage you could consider a complete change to 5.1. I used that in a Mk1 Cortina on the race track without issue (although 5.1 is not recommended for race applications)

sr2, Aug 31, 10:17am
Can I just clear things up here, and make a few sweeping generalisations re Dot ratings. Dot 3, 4 and 5.1 fluids are all glycol based; they will attract and mix with water (hygroscopic) and are rated on their ability to operate at higher temperatures, this varies from approx 140 deg C (dot 3) to approx 200 deg C (dot 5.1). The wildcard here is Dot 5 which is Silicone based,dot 5 will not attract or mix with water and is safe up to approx 180 deg C. Be aware that dot 5 will not tolerate any contamination from glycol based fluids, changing a system from glycol to silicone can be done but believe me it??

unclejake, Aug 31, 10:54am
Have you now. I ran the 5.1 for ages and then read how terrible it was.

Les Hunter sold me some new brakes at one point and just about dis-owned me when I told him. He sent me a bunch of Motul fluid - but I sold the car to a fine chap in Townsville without trying it.

Now I CBF changing my own oil! Hahaha

rsr72, Aug 31, 10:58am
Silicone-based fluid should not be used in classic car systems unless the complete system, seals, etc is cleaned out completely and all seals, and rubber lines, replaced without exception.

sr2, Aug 31, 11:53am
LOL; my 5.1 fluid costs the sponsors over $60 a litre!

xpfairmont, Sep 1, 1:11am
So it worked fine up until the point you read about it!

unbeatabull, Sep 1, 4:19am
5.1 Is fine, better then 4 & 3. It is the 5.0 you have to be mindful of. As others said, system has to be pretty much overhauled to switch over to it, or to switch away from it.

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