Bill, I may be mistaken and I have also never heard of soaking M/C or wheel
cyclinder rubber parts. If soaking swells them, how can they fit properly, hold
their designed shape and do their functions. If soaking is to be involved on
brake
parts I think it would have to be inside the parts they are to be used in, also
this brake fluid that is used for soaking is now contaminated and should not be
reused. Practicality & monatery should be watched in old car brake systems.
Bill Davies wrote:
> Hi,
> My wife (who is a professional Chemist) explained the likely problems
> with Silicone brake fluid to me some time ago, so this is not based on
> personal experience but on scientific principle. Not being a scientist
> myself, it is explained to you (as it was to me) in layman's terms!
> When new rubber components are fitted into a braking system, they are
> always soaked in brake fluid first. This is partly to provide
> lubrication for insertion, but the fluid also causes the rubber to
> swell, giving an improved seal to the cylinder bore. In theory, there is
> no problem when the same fluid is used to swell the rubber as is
> eventually used in the complete system, ie, if you're going to use DOT3
> in your system, use DOT3 to expand the seals, if you're going to use
> Silicone in your system, use Silicone to expand the seals.
> The problem arises when the type of fluid is changed between expanding
> the seals and filling the system. Different fluids have different
> characteristics when it comes to swelling rubber. The actual Chemical
> Mechanism which causes the rubber to swell in DOT3 is not necessarily
> the same as that which makes it swell in Silicone. The net result of
> mixing fluids in this way is that the rubber components MIGHT expand
> TWICE, by the two different mechanisms. This double expansion is what
> can cause the brakes to seize, effectively reducing the clearances
> between seal and cylinder bore.
> This is a theoretical situation, not one I have experienced myself.
>But
> bearing this in mind, I will not be using Silicone unless I fully
> rebuild a system.
> I hope this is of some interest,
> Cheers,
> ` Bill.
> --
> ---------------------------------------------------------
> This Message sent by:
> ^================^
> / \ William Davies
> / \ Total Triumph Enthusiast
> __ __________________ __
> / \ ______ ______ / \ 1959 Herald 948 Coupe Y128
> \__/ \ || / \__/ 1959 Herald 948 Coupe
> | A \____||____/ A | 1960 Herald 948 Saloon Export
> | = H H = | 1961 Herald S
> =====U==============U===== 1964 Herald 1200 Saloon
> \________________________/ 1966 Herald 1200 Convertible
> | | | | 1973 Spitfire MkIV
> |_| |_| 1959 Standard Atlas Pickup
|