[DeTomaso] parking brakes

[MikeLDrew at aol.com]

In a message dated 1/13/16 8 03 59, guson at home.se writes:


> That's simply not a good solution. Doesn't work as an emergency brake
> and parking brake function is dubious. If you park your car with the
> brakes hot they may release when they cool off.
> 

>>>Tomas, you're talking about a simple line lock.   He's asking about an 
(electrical) solenoid-operated system, which was pioneered by the OEMs and is 
in wide use (and is, significantly, sufficiently effective to satisfy 
government regulations worldwide).   Such systems are now available in the 
aftermarket.

I confess I don't know if OEM electric parking brake systems work by 
pressurizing the fluid in the line, or if they are a simple mechanical 'arm' that 
is pulling on a mechanical parking brake?   Does anybody know that for sure?

You're correct in asserting that a simple line lock is insufficient to hold 
a car for any length of time; they are designed for very short-term use 
only.   Geoff Peters' Pantera nearly missed (by less than an inch) crashing 
into an Aston Martin DB4 when he let a friend borrow it and the fool parked it 
overnight on a slope in neutral with the line lock engaged.   As the brakes 
cooled at night, they released and the car rolled through a lot crowded with 
collector cars, brushed past the Aston and crashed through a hedge and down 
into a ditch!   Fortunately it was unhurt, but it could have been very bad 
indeed.

A solenoid-type system that actuated the brake hydraulics would be much 
more effective because it has its own master cylinder that would still hold 
pressure even as the fluid cooled.   However, it would not serve as a proper 
emergency brake if there was a hydraulic failure (say, a seal blew out in a 
caliper) whereas a cable-type system that mechanically leverages the 
components of the caliper requires no hydraulics to work.

Mike (who has had no parking brake at all for the past 30 years...park 
wisely and hope for the best!)
-------------- next part --------------
   In a message dated 1/13/16 8 03 59, guson at home.se writes:

     That's simply not a good solution. Doesn't work as an emergency
     brake
     and parking brake function is dubious. If you park your car with the
     brakes hot they may release when they cool off.

   >>>Tomas, you're talking about a simple line lock.  He's asking about
   an (electrical) solenoid-operated system, which was pioneered by the
   OEMs and is in wide use (and is, significantly, sufficiently effective
   to satisfy government regulations worldwide).  Such systems are now
   available in the aftermarket.
   I confess I don't know if OEM electric parking brake systems work by
   pressurizing the fluid in the line, or if they are a simple mechanical
   'arm' that is pulling on a mechanical parking brake?  Does anybody know
   that for sure?
   You're correct in asserting that a simple line lock is insufficient to
   hold a car for any length of time; they are designed for very
   short-term use only.  Geoff Peters' Pantera nearly missed (by less than
   an inch) crashing into an Aston Martin DB4 when he let a friend borrow
   it and the fool parked it overnight on a slope in neutral with the line
   lock engaged.  As the brakes cooled at night, they released and the car
   rolled through a lot crowded with collector cars, brushed past the
   Aston and crashed through a hedge and down into a ditch!  Fortunately
   it was unhurt, but it could have been very bad indeed.
   A solenoid-type system that actuated the brake hydraulics would be much
   more effective because it has its own master cylinder that would still
   hold pressure even as the fluid cooled.  However, it would not serve as
   a proper emergency brake if there was a hydraulic failure (say, a seal
   blew out in a caliper) whereas a cable-type system that mechanically
   leverages the components of the caliper requires no hydraulics to work.
   Mike (who has had no parking brake at all for the past 30 years...park
   wisely and hope for the best!)