Date: Wed, 25 Mar 1998 17:33:26 GMT From: joenopsamoresource.com (Joe Way) Subject: Re: silicon brake fluid
On Mon, 16 Mar 1998 15:04:44 GMT, edselnetnopsamrnet.ab.ca (Michael Brusselers) wrote: >I'd like to add my two cents worth: > >While I have been using Dot 5 brake fluid in all of my vehicle for >several years I still can't conclusively say that it is better or >worse. I am considered hard on my vehicles and I have yet to have a >problem with Dot 5, on the other hand I never had a problem with using >Dot 3 or Dot 4 in the appropriate applications. I have never had a >brakelight switch problem with european or japanese cars with Dot 5 >but I did have problems with and Edsel's brakelight switch. After >investigating the problem further it turns out that many '50's and >60's Fords are prone to problems after you switch to Dot 5. The >problem does not occur when you replace the switch at the time you >change to Dot 5. On old Fords this is a $5.00 part. The mistaken >assumption with Dot 5 fluid is that once in place you can forget about >it. Bleeding your breaks periodically makes sense no matter what you >use. I bought quite a bit of Dot 5 fluid and I will use it up in any >case, if I buy it again will depend on how much I like using the rest >of it up. So far I have been happy with how well it's worked with >vehicles that I park for longer periods of time. If you buy Dot 5 at >regular retail in small quantities it is definitely not worth the >money. Though when buying larger quantities it is handy to know that >Dot 5 has an infinitely longer shelf life than Dot 3/Dot4 fluids. > >mpb ==== Interesting comments. This is the first I've heard that replacing the switch is a one-time thing. I've talked to people who have replaced several switches, at fairly regular intervals, they implied, after the change to silicone. You are absolutely right about the periodic bleeding, regardless of type of fluid, and it is particularly important on vehicles with vented master cylinder caps. This includes most of the old cars that seem to get converted to silicone in the highest proportions. The following paragraphs are written in an Edsel context, but are applicable to some other makes in the cross-posting; Saab, Honda and Ford that I know of for certain. Edsel owners should note that some FoMoCo vehicles--possibly including some Edsels, but I don't know--were equipped with a Midland brake booster. This booster has a control port piston and seal with manifold vacuum on one side and brake fluid under pressure (during brake application) on the other side. If the control port bore or seal are defective, brake fluid will be sucked into the intake manifold and burned in the engine. I know that some Edsels have the Bendix Treadle-Vac brake booster, which is subject to the same leakage of fluid. In the T-V, the fluid path is along the pushrod and past the seal at the mouth of the cylinder into the vacuum side of the booster. The chief byproduct of combustion of silicone fluid is a very aggressive abrasive that will eat an engine in short order. If your car, Edsel or other make, has either type of booster *be sure* it is in good condition before you put silicone in it. Speaking *very* generally, if the fasteners holding the master cylinder to the booster can be removed from the master cylinder side, it is probably not subject to this failure mode (at the very least, simultaneous failure of master cylinder seals AND booster seals must occur to allow leakage to the engine, and the master cylinder seals in question are not under pressure). If the booster must be disassembled to remove the fasteners holding the master cylinder on, or the master cylinder has a vacuum diaphragm mounted on the side of the cylinder, it is subject to this failure mode. The side-mounted diaphragm category includes many imported cars into the late '60s and early '70s, as well as older Midland-equipped vehicles. Joe ==brake cylinders sleeved with brass== ==One-Wire conversions and rebuild kits for GM alternators 1963-85== ==Quincy, CA==
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