[DeTomaso] Master Clutch Cylinder

Thu Jul 17 14:00:48 EDT 2008

Probably not Dot 3 vs. Dot 4 . . . I was thinking that possibly using  
HOZip9 El cheapo elephant snot brake fluid (instead of quality stuff)  
was having an effect on the rubber.  I believe we can discount that now.

David

Quoting Tomas Gunnarsson <guson at home.se>:

> I seriously doubt that the problem is that one uses DOT 4 instead of  
>  DOT 3. I've not run anything but DOT 4 in any of my cars for the   
> last 20+ years, in the Pantera for 12 years now. I don't even think   
> DOT 3 can be found on the common market (read: gas station etc) over  
>  here.
>
> Tomas
>
> ----- Original Message -----
> From: "Trevor Fougere" <trevor at fougere.com>
> To: <detomaso at realbig.com>
> Sent: Thursday, July 17, 2008 8:00 AM
> Subject: [DeTomaso] Master Clutch Cylinder
>
>
>> Well...on the plus side I've run 5,000 miles on it after replacing the DOT 4
>> that had been in there for the previous 5,000.
>>
>> This change over was after a debate, of sorts, with the Pantera Community
>> insisting on DOT 3 or DOT 3/4.  Versus
>> DOT 4 arguments.
>>
>> The fact is the seals in my 3rd Master Clutch Cylinder are disintegrating.
>> At least they didn't disintegrate immediately upon
>> installation like the 2nd one, or soon after I purchased the car as with the
>> 1st MCC.
>>
>> Frankly, the whole subject confuses me. The following Wikipedia entry seems
>> to imply that DOT 4 would be better.
>>
>> Trevor
>>
>>
>>
>> According to Wikipedia: http://en.wikipedia.org/wiki/DOT_3
>>
>> DOT 3 is one of several designations of automotive break fluid, denoting a
>> particular mixture of chemicals imparting specified ranges of boiling point.
>>
>> In the United States, all brake fluids must meet federal standard #116.
>> Under this standard there are three DOT minimal specifications for brake
>> fluid. They are DOT 3, DOT 4 and DOT 5.1
>>
>> DOT 3, like DOT 4 and DOT 5.1, is a polyethylene glycol based fluid
>> (contrasted with DOT 5, which is silicone based). Fluids such as DOT 3 are
>> hygroscopic and will absorb water from the atmosphere. This degrades the
>> fluid's performance, and if allowed to accumulate over a period of time, can
>> drastically reduce its boiling point. In a passenger car this is not much of
>> an issue, but can be of serious concern in racecars or motorcycles.
>>
>> As of 2006 most cars produced in the U.S. use DOT 3 brake fluid.
>>
>> Girling brakes, which were widely used in British cars in the mid-20th
>> century, use nitrile seals, which are degraded by DOT-3 brake fluid. Many
>> owners of British cars had no problems with their brakes as long as their
>> brakes were serviced by a British-car dealer who used the
>> Girling-recommended "Castrol Golden Amber" brake fluid, but at some
>> indeterminate time after allowing a non-specialist mechanic to top up oil
>> and "all fluids," felt their brake pedal go to the floor without stopping
>> the car. The problem: the generalist mechanic used DOT-3 brake fluid in all
>> cars and rarely sees a British car (twice). The solution-after body
>> repair-is to drain the brake system and rebuild all cylinders with new
>> nitrile seals, then fill the system with the Girling-recommended fluid.
>>
>> Boiling points
>>
>> Minimal boiling points for these specifications are as follows:
>>
>> (C-Centigrade, F-Fahrenheit)
>>
>> Dot 3    205C (401F) Dry, 140C(284F) Wet
>>
>> Dot 4    230C(446F) Dry, 155C(311F) Wet
>>
>> Dot 5    260C(500F) Dry, 180C(356F) Wet
>>
>> Dot 5.1    270C(518F) Dry, 191C(375F) Wet
>>
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