505 brake fluid - To DOT 3 or not to DOT 3?

Hugo

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Fellow Frogger
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Aug 4, 2013
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Melbourne
Hi all,

Looking to flush the whole brake system of my 1993 505 GTI wagon and was wondering if I should use DOT 3 or DOT 4 brake fluid.

Firstly, sorry in advance for raising such a well worn and potentially divisive topic :), but I'm having trouble deciding rationally. :crazy:

The Penrite site says something like DOT 3 is preferred and DOT 4 is a reasonable alternative, so I'm thinking of using DOT 3. But what do you reckon?

Cheers,
Hugo
 
Hi robmac,

That makes sense - thanks for that. DOT 4 it is then. :)

Cheers,
Hugo
 
Just to add a hand grenade.... :)

Perhaps for a later overhaul, some of us have been using Dot 5 (silicone) brake fluid for many years (25-30) and no corrosion, no regular changes, no seized pistons, no problems. Perfect for cars with intermittent use.

Just a thought and to encourage discussion.

Cheers
 
Just to add a hand grenade.... :)

Perhaps for a later overhaul, some of us have been using Dot 5 (silicone) brake fluid for many years (25-30) and no corrosion, no regular changes, no seized pistons, no problems. Perfect for cars with intermittent use.

Just a thought and to encourage discussion.

Cheers

I'd only use Dot 5 if the entire braking/clutch system has been fully dissembled and all lines/ hoses cleaned and blown through with a solvent. You also need to disassemble and clean the booster.

Otherwise the risk of contamination and an adverse reaction is too great.
 
Absolutely right re the cleaning. I changed my Renaults to silicone only at a time when I was doing a full brake overhaul with new seals and hoses. Very good result but it does need doing meticulously AFAIK.
 
The best outcome is that spills of silicon fluid won't destroy the paint.

You also need to label the vehicle that the fluid has been changed to dot 5 silicon fluid. :rolleyes:
 
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