Please pardon the interruption.
Knowing that all LBC fans are environmentally aware prompts me to share a
recycling tip: save all the old DOT 3 & 4 brake and clutch fluid from your
annual
or semi-annual fluid purges. When the time comes to repaint your car you can
drag
out your barrels of old fluid and use it as paint remover. Not only does it work
better, but you will save all the money you would have spend on Aero stripper.
It
is very beneficial to your health that you won't be inhaling all those nasty
carcinogenic aromatic hydrocarbons and solvents.
I say Let the Argument Rage On!
Jim
Ajhsys@aol.com wrote:
> In a message dated 2/22/00 7:54:19 PM Eastern Standard Time,
> barneymg@ntsource.com writes:
>
> << When the system was repacked I switched from silicone fluid to Casterol LMA
> DOT-4 fluid, just out of curiosity. Shortly thereafter the brake pressure
> switch failed. I wouldn't say that had anything to do with the DOT-4
> fluid, any more than it had anything to do with the DOT-5 fluid. It was
> just time for the switch to expire, that's all.
>
> Otherwise, I think maybe I don't like the DOT-4 fluid. After about six
> months I had to R&R a short section of steel brake line at one front wheel
> while I was replacing a worn lower swivel link. When I bled the brakes
> afterwards the fluid was pretty black with disolved and suspended rubber
> particles, so I flushed the whole system. Because of this, about six
> months later I bled the brakes again just to check, and sure enough the
> fluid was quite dirty again, and so I flushed the entire system again. I
> never had this problem with the silicone fluid, so naturally I'm a litle
> concerned about this. Would anyone care to venture a guess whether this
> condition may be an effect of the DOT-4 fluid, or maybe some inferior
> rubber products having gotten into the system with the last rebuild? And
> FWIW, all the rubber hydraulic parts came from Moss Motors. >>
>
> - - - - - - - - - - - - - - - - - -
>
> First of all, I want to say that there are very few opinions on this list
> that I respect as much as Barney's. He will forget more than I will ever
> know about British cars.
>
> Barney, I suspect that the two brake fluids may have interacted to cause the
> brake light switch to fail. One of the problems is the differing amount of
> fluid that can be absorbed by the rubber bits when switching fluids. I
> believe the problem as stated when DOT 5 first appeared, was that DOT 4 fluid
> (originally supplied with the car) caused the seals in the brake light switch
> to swell, and switching to DOT 5 allowed them to shrink and leak. I haven't
> checked the archives, but that is my recollection. Since the fluids cause
> swelling at different rates, that may be why the switch failed, even though
> you went from DOT 5 to DOT 4.
>
> Could the rubber, or black contaminent, in the fluid be coming from the brake
> switch, rather than the new seals? Was this only found in one wheel line, or
> throughout the brake system, which would indicate a particular cylinder or
> possible the MC?
>
> Somewhere at home I have an article written by Lockheed after testing DOT 5
> brake fluid and concluding that it should not be used in any system with a
> Lockheed brake light switch. If I can find it, I'll let you know.
>
> Allen Hefner
> SCCA Philly Region Rally Steward
> '77 Midget
> '92 Mitsubishi Expo LRV Sport
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