Porsche Enthusiasts Club Forum

Hi guys, sorry if this has been asked a million times before - i did search but got some weird results (internet dummy)

Anyway - we went to bleed the brakes last night as saw that on the brake fluid cap it said DOT 3 only - we had bought DOT 4, would this be OK to use or does it have to be DOT3 (I'm guessing it just means nothing less than DOT 3?)

One other thing could someone tell me (or show via pictures ) where the clutch master bleed valve is?

Thanks for any help

Mark.

I thought you had to use the correct DOT as there is a difference between synthetic and mineral based fluids.

A common misconception Sean! All brake fluids excluding Citroen (old ones) & RR are synthetic. In theory all DOT markings of brake fluid are intermixable in fact part of the DOT standard makes it the rules. So DOT 3 can be topped up or replaced by 4 or 5 or 5.1, however I've heard of some cars having problems with DOT 5.1 especially if being bleed through & NOT a total rebuild, some Alfas for one are prone to this.
DOT 5 is Silicone & has the advantage of not absorbing water, which means no rust issues in wheel cylinders. It was originally designed for US Military vehicles & actually has a MIL spec to it. But some people have issues with seals swelling & some cars end up with a spongey brake pedal. I've known lots of classic owners run it with no issues & I know someone who raced with it successfully with no problems. Another BIG advantage is that it doesn't ruin paint, in fact it makes a half decent polish. To get the full benefits you need a complete strip & rebuild to get the old stuff out, otherwise you don't get the full advantages.
Mineral is used in fully pumped integrated systems like Rolls Royce & Citroen use, where brakes, suspension etc. are all run off a pump like a PAS pump.

DOT 4 will be fine for your brakes and the clutch is bled via the slave cylinder (next to the starter), its best to remove the starter for better access. Make sure you disconnect the battery first as the starter is permanently live. A pressure bleeder (like Ezibleed) makes things alot quicker and easier.

Ta muchly