Correct Brake Fluid 1950 MK V ?

Edited on 2013-11-17 23:20:40
Phillip, I have been using silicon for over 30 years and have used it in every kind of vehicle but mostly Rolls/Bentley and Jaguar. I have never heard of a brake hose collapsing due to silicon or mineral, Just two weeks ago we had a collapsed hose on a 140 so we changed all three. The vast majority off British cars used dot 4 NOT dot 3, jaguar was always 4. I do stock dot 3 for use in American cars most of which use dot 3. The mineral oil has a similiar viscosity to silicon -perhaps someone can verify- and many cars are now using it. I started using it on Rolls Royce many years ago in place of dot 4, Interestingly, Citroen, who patented the Rolls Royce accumalator brake system used mineral oil. In my military experience, mostly armoured vehicles- from the 50's- mineral oil was used in the accumalator systems. One more benefit of the Silicon is the fact that it is lubricant, traditional brake fluid IS NOT. These days, if we get a classic which has the old fluid we suggest converting to silicon and many times we just bleed out the system and stop when the silicon comes out clean. We also put a notice on the reservoir in case the car gets into somewhen elses hands.

Curt, after reading Williams comment about its viscosity, and Georges comment about ABS, I can now understand why it is not used in new production. Since all cars nowadays come equipped with ABS pulsating brakes, the silicone would have a slightly slower reaction time. If I can recall, my 1995 XJR had mineral fluid, and never had a problem in the 15 years that I owned it.
I might also add that my 1982 XJS that I replaced the DOT 3 with DOT 4 had serious issues. All of the brake hoses collapsed from the degregation effects of the chemicals within the DOT 4. My 1982 XJS was still with the original brake hoses that were designed for DOT 3. In collapsing the rear brake hoses, my rotors became red hot, and destroyed the callipers/pistons.
I had a similar situation with a 1970 Silver Cloud. I never figured what had caused it at the time.
My recomendation would be;
1) Silicone
2) Mineral
3) DOT 3, and change it every 3 years
Happy Motoring

Phillip I have used it since 1980 or so. Never an issue but I started as I had seen the savings on fleet operations--huge. I think the main issue with using it in new cars is that it does not work with ABS. Not sure but I think that is one of the main reasons.

Ahh! Its the paint manufactures and paint refinishers that must like it. Spill some on a fender and you will see.

William, which makes me wonder...why are car manufacturers still using Dot3, Dot4, rather than Silicone? What am I missing?or better yet, what are they missing?

Silicon fluid is, in my opinion, the best choice , I started using it around 1984, and have used it ever since in my El Camino, it still has it. The only thing I do differently is to bleed it slowly, it is a thicker fluid and so the air bubbles move slower. Philip, I believe the Siliccn has a HIGHER boiling point. It has long been used by Harley and many other vehicles.

Curt, I would use silicone brake fluid, now that this is a new system. DOT3 and DOT4 will both attract water unless you keep flushing it every few years. Keep in mind that DOT 4 may have a higher boiling point than Silicone, however you have simple drum brakes in your MKV.
I had used Silicone in my 65 Mustang 20 years ago and have not touched it since. I wish I had done that to all of my Jaguars.