johnfin

When adding new clutch parts to my 85, which fluid, 3, 4 or 5?

84 4+3

Dot 3 or 4... dot 4 has a higher boiling point. Dot 5 is silicone... you could use Dot 5.1 which is compatible with 3/4. I'd use Dot 4 as it's available pretty much everywhere and inexpensive.

Blue Bucket List

In a clutch application I think 3 would be fine as not much need for higher boiling point there. Also, 3 is less likely to absorb moisture than 4 from what I have read. If you are thinking of a brake flush also than it would be best to do both with the same and have less chance of a half empty bottle sitting around absorbing moisture.

phaze426

When we replaced the hydraulics on my son's, we went with one by Valvoline labeled as "Synthetic DOT 3 & 4." I had read somewhere that it's what Bill Boudreaux recommended. It's seemed to work alright for us, though we're admittedly not using the car in a very demanding way where we'd have to worry about burning/boiling the hydraulic fluid.

rocco16

I don't think anyone has to worry about overheating clutch hydraulic fluid.

LiveWire1

In my 85 4+3, I put Dot 5 silicone brake fluid in the clutch system. It doesn't attract moisture, so it's good for a long time. The 85 doesn't have ABS, so I put it in my brake system as well. DOT 5 Silicone foams with ABS brakes.

Blue Bucket List

If you do decide to go with 5 be sure that you flush the system well as 3 and 4 don't play well with 5.