Thanks Arno and Orson.
I shall give this up as a foolish idea.
I contacted Bel-Ray and received the following response this morning. It agrees with you 100% and sheds light into some dark crevices.
Here it is in full for everyone's information:
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Dear Ivan,
Thank you for your e-mail and interest in Bel-Ray products. Bel-Ray DOT 5 Silicon Brake Fluid is not recommended for ABS brake systems. DOT 5.1 is generally used in ABS applications and was developed for it. DOT 5.1 has a very low viscosity that assists the modulation of the ABS system.
Today DOT 5 silicon brake fluids are mainly used in Harley-Davidson
motorcycles since this is what comes from the factory and the advantage is
if any fluid spills it won't damage the custom paint jobs. Even road race
teams are using DOT 4 or DOT 5.1 because they have extremely high wet
boiling points. Years ago they went to DOT 5 silicon to get high boiling
points, but today's technology has advance DOT 4 and 5.1 brake fluids beyond that of silicon. Another problem of switching your brake system over form glycol to silicon is if any remnants of the glycol remain in the system and it mixes with the silicon it will coagulate. You can imagine the problems, so it is advised to do a complete seal and 'o' ring replacement when switching to avoid problems in the future.
One other thing in America the brake fluids names are: DOT 3, DOT 4, DOT 5 and DOT 5.1. All are glycol and compatible with each other except for DOT 5 which is silicon. In Europe they do not recognize DOT 5 silicon and therefore call DOT 5.1 which is a glycol product DOT 5! This can cause great confusion and obvious problems. So be careful as your Volvo
may indicate DOT 5, but what they really mean is DOT 5.1.
Good luck on your brake fluid quest and you may contact me directly if you
have further questions.
Best regards,
Joe DeGano
Bel-Ray company, Inc.
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Cheers and thanks again. --
Ivan form Oz