hydraulic clutch

[makser]

Can you put dot 4 hydraulic clutch /brake fluid in a reservoir that specifies dot 3 in a 2002 rt10 ? Its harder to get dot 3 now .The dot 4 container i have has all the writing in german so i cant tell wether its compatible ? The chap at the car shop says going up a number is fine but going down a number isnt !

[fatboy18]

Yes you can, but I would bleed out all old fluid

[makser]

Oh right .Why is that ? Do you think that is necessary ?

[ViperDave]

DOT 4 and DOT 5.1 are backwards compatible with DOT 3 as they are all glycol based fluids, the higher numbers are later fluids and have higher boiling points. DOT5 on the other hand is silicone based and not compatible with the others without a full flush and worry about seals etc.

Its a good idea to bleed out the old fluid so that you get fresh new stuff down where it is needed rather than just refreshing whats in the reservoir, that can be a a bit of a pain, bit not that big of a deal on a viper, replacing whats in the reservoir should however help if at a push and you really don't have time or the inclination to do it properly, Brownian motion will see to it that the new fluid will draw out the the water and impurities in whats left of the old, but I'd postulate its effectiveness is probably mild at best and non existent for particle contamination, and if you change the fluid this was then you should be doing it quite regularly and probably still do a flush occasionally.

If you don't flush DOT 3 out and put DOT 4 in, i don't think it would cause you any issues, but you wont really get many, if any, of the benefits of new fluid let alone the higher spec fluid

Edited by ViperDave on Monday 21st March 19:22

[Viper]

Chuck told me the simplest way is initially, suck out the reservoir with a syringe, fill back up
press the clutch x30 times, and repeat this process x2 more times

then several months time do it again to keep on top of it

[makser]

Thanks .Like many supercars i think it pays to ask before you do anything or else dire consequences may ensue .I like the use of the word - "postulate" to ! I dont know really what it means but once i do i will maybe use it now and again ! Cheers .