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PostPosted: November 10, 2019, 2:02 am 
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Joined: November 11, 2013, 4:47 am
Posts: 405
Location: No. Nevada
Maybe I'm missing something obvious?
It seems to me that it should be possible to activate just the rear brake calipers using a second MC when we have separate circuits.
Recently got my Jag IRS back from rebuild with custom 3.90 ratio.
Being a Power-Loc it has only one mechanically operated parking brake fitted to one disc.
But I'm questioning the need for that extra part to be there at all.

Since I intend to do some more disc brake conversions I'm looking for simple ways to handle the parking brake.
So the idea of just fitting a second MC activated by the parking brake handle is attractive, and Locost@! :)

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PostPosted: November 10, 2019, 10:08 am 
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Joined: July 17, 2008, 9:11 am
Posts: 4129
Location: West Chicago,IL
As far as I know, the rule for parking brake is, if any part of the main braking system fails, the parking brake should be able of holding the vehicle on a 20 deg incline. Using the caliper seals and brake lines to do double-duty seems to be contradictory to that design rule, if it is a rule at all.

Here is the relevant NSTSA test regiment. It may help you decide what you need to consider. https://www.nhtsa.gov/sites/nhtsa.dot.g ... 135-01.pdf

On a second note, I personally would not trust a brake caliper to hold pressure for days on end.

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PostPosted: November 10, 2019, 12:57 pm 
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Joined: April 23, 2006, 8:26 pm
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Hydraulic brakes are not designed to be under pressure for long periods of time. With your proposed setup, if there is any leakage, even seepage, over time it will reduce the clamping force to the point that the car will roll. It'll work, short term, but not how you want.

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PostPosted: November 10, 2019, 3:41 pm 
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Joined: March 19, 2011, 10:22 am
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Location: Holden, Alberta, Canada
My opinion of a park brake or emergency brake is a manually operated cable system that will apply the rear brakes in the event of a hydraulic brake system failure. Being a cable system it is not married in any way to the function of the hydraulic system, thats why it's used in case of emergency or to lock the rear brakes when parked to prevent the vehicle from moving.
There are hydraulic 'line locks' on the market, I don't know if they promote these as park/emergency brake alternatives.
I believe most auto manufacturers use a cable type park/emergency brake system, but I could stand to be corrected.

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PostPosted: November 10, 2019, 10:27 pm 
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Joined: November 11, 2013, 4:47 am
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Location: No. Nevada
Line-Loc is common on heavy equipment.
Personally I never depend on the parking brake to hold a vehicle in place, usually park in gear.

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PostPosted: November 11, 2019, 10:18 pm 
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Joined: January 18, 2015, 2:34 am
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Location: Los Angeles
My Birkin uses rear disks/calipers from a 1998 VW GTI. This allows for a cable operated, mechanical engagement of the pads. Works great!


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PostPosted: November 12, 2019, 1:22 am 
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Joined: November 11, 2013, 4:47 am
Posts: 405
Location: No. Nevada
papak wrote:
My Birkin uses rear disks/calipers from a 1998 VW GTI. This allows for a cable operated, mechanical engagement of the pads. Works great!


Problem with that is that I'm trying to come up with something to upgrade Land-Rover 101's.
It's been done before but the price was pretty crazy.
So then they stopped making them due to low sales volume. :roll:

So I'm looking into doing a less expensive version.

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