Professor Vannice might be able to speak to this subject from a better chemical engineering perspective, but fluids will mix and travel throughout a brake system better than one might think. Witness the corrosion in wheel cylinders with the only source of the necessary water/moisture/oxygen coming from the exposed brake fluid surface in the master cylinder reservoir. Moisture and oxygen from the atmosphere enters the brake fluid at this surface, travels throughout the brake system and provides the necessary electrolyte and oxidizer for corrosion. Glycols preferentially absorb moisture and this is probably one of the reasons for going to a silicone-based hydraulic fluid. The bleed valves at each wheel cylinder are positioned at the top inlet of the wheel cylinder to effectively remove air bubbles, but cannot be expected to provide a thorough flush of the liquid in the wheel cylinder.. Whatever liquid is in the wheel cylinder will pretty much stay there, even if the lines going to the cylinder are flushed with air, alcohol, new brake fluid, or whatever. Flushing the system does clear out the master cylinder and brake lines and this is a good thing to do periodically. If one is concerned over the liquid in the wheel cylinders, disassembly, draining, cleaning and reassembly with new "kits" is probably in order. I have seldom seen anything good inside of old wheel cylinders. The brake fluid tends to be red with rust from the system. Fortunately, the pistons and sealing cups tolerate this gunk pretty well, otherwise, more of us would be in deep doo-doo more often due to failing/leaking wheel cylinders. If there is any possibility of the hydraulic fluid turning into foam, gel, emulsion or gunk, I'd think it would be time to completely flush the system, including the wheel cylinders. The problem might become even worse at high or low temperature extremes. In order to keep you and your Chrysler 300's intact, care and cleaning of your brake systems is highly recommended. C-300'ly Rich Barber Brentwood, CA 1955 C-300 Charlie Valentine wrote: >Just an idea !!!! If you disconnected the brake line at the master >cylinder and at each wheel cylinder and used compressed air to blow the >lines clean first, then the lines are pretty clean and you are flushing them >minimally and the new fluid is mainly flushing the wheel cylinders. Also >when you disconnect the line from the M.C. would most of that fluid drain >out on its own? >My thinking is if the master cylinder and brake lines and hoses are 90% >clean from the compressed air, the new fluid will have minimal "old stuff" >to mix with and you just might get a cleaner flush. > >Any thoughts, comments and advice, be they good or bad, on my terrific idea >would be greatly appreciated. >Bye for now and have a wonderful holiday weekend. > >Charlie Valentine >300G, 62 300 Sport Convertible > >----- Original Message ----- >From: "Warren Anderson" <wranderson@xxxxxxxxxxxxx> >To: <L-FORWARDLOOK@xxxxxxxxxxxxx>; <Chrysler300@xxxxxxxxxxxxxxx>; ><mjraguse@xxxxxxx> >Sent: Saturday, May 28, 2005 12:39 AM >Subject: Re: [Chrysler300] Dot 4 mixed with Dot 5 Silicone > > > > >> >> >> >>>I have just discovered that one of my cars which I thought had Dot 3 or 4 >>>actually has silicone and last month I topped off the master cylinder >>>with >>> >>> >>Dot 4. >> >> >>> I am sure I am not the first to do that so what is the prognosis? I can >>>syphon off what is in the master cylinder but by now all sorts of mixing >>> >>> >>action >> >> >>>has occurred. >>> >>>Marv >>> >>> >>Answers to your questions are available from many good sources. I would >>suggest a Google search. >> >>Personally, I like and have systems with DOT 5 fluid in them. Does what I >>want; fluid stays clear and does not attract moisture like DOT 3, 4 do. >> >>I understood a long time ago that adding DOT3, 4 to a DOT5 system derates >>the DOT5 fluid but is 'compatible'. But the mixture of DOT3,4 and 5 is not >>desirable at all and can lead to a system with strange looking gunk in >>it. >> >>If I had a system with DOT5 that had to be topped off with DOT3,4, in an >>emergency, I would draw out all fluid from the master cylinder as soon as >>possible and flush and refill the system with straight DOT5 fluid. Brake >>fluid only is best to flush the system with and definately not alcohol >>(from >>my manuals anyway). Some hydraulic parts were never designed to work with >>alcohol (and NO brake part will live when contaminated with anything >>petroleum based). >> >>Warren Anderson >>Sedona,AZ >> >> > > ------------------------ Yahoo! Groups Sponsor --------------------~--> What would our lives be like without music, dance, and theater? Donate or volunteer in the arts today at Network for Good! http://us.click.yahoo.com/2xaSZB/SOnJAA/Y3ZIAA/8LmulB/TM --------------------------------------------------------------------~-> To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/