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[VintageLambo] Re: Espada right front hub running hot- possible caliper sticking

lgpdk

I had my calipers rebuilt as well some 8 years ago with the same rust pitting problems on the pistons, although there were no functional symptoms. I too am using DOT 5 fluid (since 1987) and believe it is ideal for our kind of cars. Very benign toward rubber seals, hygroscopic and paint even looks better after a spill and wipe off, try that with DOT 3 or 4 fluids. I recently checked into the pros and cons of silicone fluids (DOT 5) and there plenty of opinions and advice available, so I asked one of my colleagues (chemist PhD with specialty in silicones) and came to the conclusion that the only potential drawback of using silicone fluids is its high oxygen absorption, which is released as bubbles during rapid altitude changes. So here is an advice: don"t participate in the Pikes Peak race with silicone brake fluid. Another cautionary note is: don"t drop water in the fluid, since the water (as the heavier component) eventually will settle in the calipers with potential rust problems as a result (similar to rusted gas tanks from the inside). Having a sense that the vacuum capacity in my Espada brakes was less than it should be (2 or 3 pumps and the vacuum is gone) and having read here that the vacuum tank easily gets filled with brake fluid and engine oil, I decided to take the tank out for cleaning. The car had been sitting unused for 2 months and to my pleasant surprise there was a loud sucking sound when I disconnected the vacuum hoses (still vacuum after 2 months). That in spite the fact that my Girling boosters have never been rebuilt (just painted). The vacuum tank was dirty on the outside but "baby fresh" on the inside. So I only need to do some cleaning and better change some hoses while there. A little detail that may be important is the sealing of the odd angled plastic connector to the brake booster tanks. They have a rubber washer that I typically spray with silicone while wiggling the connector. I also ensure that the relatively stiff connecting rubber hoses do not misalign the connector too much. A little terminology: hygroscopic is (almost) the same as hydrophilic and hydrophobic is the opposite. A hydroscope is used for looking under water. Yes, I cheated and looked in Webster. Lastly, at the recommendations of a few, I am slowly creating a list of what I consider to be design flaws on the Espada and once again, the list is short. Laust --- In VintageLambo@yahoogroups.com, "Jack Riddell" wrote: > Hi Shel, > > All the replies so far are worthy of consideration. I think Lars has defined the most probable cause - a caliper problem. Like he pointed out, the original pistons are chrome-plated steel and the chrome plating flakes off over time and can cause a seal to become less efficient. Like Fred pointed out, I just finished rebuilding my rear calipers last week as part of a project where I am restoring my entire rear suspension. You can order caliper rebuild kits and replacement pistons from GT Car Parts. The replacement pistons from GTCP are made of stainless steel - big improvement. FWIW, I have used DOT 5 fluid in my car for the better part of 15 years with no detrimental effect on seals. The DOT 5 is silicone-based and repels water (is "hydroscopic") so your system is not so susceptible to accumulating moisture and the corresponding problems it brings. > > Take a look at:http://www.geocities.com/lamboguy/Calipers.html This is a short procedure I created when I rebuilt my front calipers. The rears are pretty similar except for the emergency brake components. > > Best Regards, > > Jack > > > > ----- Original Message ----- > From: shel_elias > To: VintageLambo@yahoogroups.com > Sent: Friday, December 12, 2003 6:29 PM > Subject: [VintageLambo] Espada right front hub running hot- possible caliper sticking > > > Hello: I think my right front caliper is<