[DeTomaso] parking brakes

[Tomas Gunnarsson]

Mike,

Bill originally wrote: Something that that blocks fluid in the brake
lines to hold calipers pressed against the rotors.


Aka line loc.


OEM electric parking brakes work by having an electric motor actuate the
brake via a mechanical device, like a wire.


Tomas



<-----Ursprungligt Meddelande----->

 	 	From: Mike Drew via DeTomaso [detomaso at poca.com]
Sent: 13/1/2016 8:51:53 PM
To: guson at home.se;gaino at earthlink.net
Cc: detomaso at poca.com
Subject: Re: [DeTomaso] parking brakes 


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 --------------
   Mike,

   Bill originally wrote: Something that that blocks fluid in the brake
   lines to hold calipers pressed against the rotors.

   Aka line loc.

   OEM electric parking brakes work by having an electric motor actuate
   the brake via a mechanical device, like a wire.

   Tomas
   <-----Ursprungligt Meddelande----->
       From: Mike Drew via DeTomaso [detomaso at poca.com]
   Sent: 13/1/2016 8:51:53 PM
   To: guson at home.se;gaino at earthlink.net
   Cc: detomaso at poca.com
   Subject: Re: [DeTomaso] parking brakes
   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!)