Advice on a mechanical parking brake that works?

[PeterAllen]

I've looked at the larger Wilwood brake but I would have issue routing the cable.

[mln385]

Originally Posted by joyridin'

What do they do with a stick shift car? Rev it to 1200-1500 RPM and release the clutch?

Yes, the e-brake needs to hold and stall the motor.

[Lexluther]

Australian vehicle design rule 31/02
(Brake system for passenger cars)

5.1.2.3. Parking braking system

The parking braking system must make it possible to hold the vehicle stationary on an up or down gradient even in the absence of the driver, the working parts being then held in the locked position by a purely mechanical device. The driver must be able to achieve this braking action from his driving seat

Seems pretty straight forward to me, or am I missing something?

[Modena]

Well it perhaps isn't quite that simple Lex. The 105 page instrument is here, and includes testing data and methods on different levels of adhesion on different surfaces, and all manner of lawyer inducing other goodness if you can't get to sleep;

https://www.comlaw.gov.au/Details/F2...d-88c0a4aca3ce

[Modena]

E.g. refer 2.3.1 as an example;

The parking braking system must be capable of holding the laden vehicle
stationary on a 20 per cent up or down gradient

[Rob. Smith]

I proved my park brake on the back of a tilt tray truck...30 deg angle no probs. Its a modified jag set up with linkages instead of cables. The only problem I had was ..there was no force / effort on the hand brake lever. I had to fit a spring to that to give it "feel"

[PeterAllen]

See p.37.

http://roadsafety.transport.nsw.gov....manual2013.pdf

Not sure what this document is about but at least I know I wasn't dreamin'.

[leroy17]

Peter, I know that it may be like starting again, however these seem to have been used on GT40's, Pantera's and some others as well. I have no experience with this brand, but posting as a suggestion.

Mechanical Parking Brake Calipers

[PeterAllen]

Thanks Leroy. I looked at those and read the forum post suggesting they were superior to the Wilwood. While they appear to be a higher quality I'm not convinced it's a matter of quality but more one of size/capacity.

Wilwood don't state what compound their pads are comprised of but they appear ultra hard and mine glazed very easily. I thought I would make some up of softer compound and increase the area while I was at it. I was hoping a better CoF might help.

I cut up some Corolla pads and fly-cut the thickness down - Gee, didn't that blunt the tip very quickly!



I machined a spigot on a new locating plate and welded the locating plates onto the pad backing plates.





The extra pad thickness required an extra 12mm spacer.



The performance is much improved but still not capable of holding the car against 1st gear, however, as I now understand it, that requirement is in lieu of 1:5 test slope being available.

The reason I'm going to these lengths to keep using the Wilwood is that a lot of engineering has gone into the cables and mounting brackets. If, like you, I was still in the design phase and knowing what I know now I would go with the later, larger, Wilwood mechanical brake. Better still I would see what drum in hat options I had.

[CHANMADD]

A big V8 , 1st gear .........no parking brake will hold. I have always tested that by putting the gearbox in 3rd, and it should kill the motor right away.
Another thing .......there is a difference between a "Parking" brake and a "hand" brake. These are all parties raking brakes. The only parking brakes that really work as a brake are the type with a drum style. The swept area of the shoes is what is important here. Swap the brakes for a style that has the drum brake in the hat..

[Aussie Mike]

Just a thought... If it's just a matter of getting through the test how about dropping the idle speed? Also are you trying it cold when the idle is up or after it's warmed up?

Cheers

[leroy17]

Nice work Peter and I understand why you are sticking with Wilwoods.

I am coming to the conclusion that these will be no more than a parking brake (just to hold car in place). Where in my mind I am picturing something to the performance of a WRC car (delusional.... yes.... but you never know).

I like the bigger Wilwoods, however it does not appear that they will even come close to fitting with the size of the backs near the Jag diff.

Anyway, good work and the improvement may be just as is needed along with a lower idle like Mike suggested.

[Shootnride]

Peter,

My SPF uses the same Wilwood emergency brake caliper as your car. When I got the car, the emergency brake was completely useless. On my first attempt to improve its function, I made a longer actuating arm for the caliper. This helped, but still not adequate. I put the stock arm back on an went another direction. I fabricated a simple lever arm and mounting bracket to provide some compound leverage. Although I would not consider it's performance as outstanding, it will now prevent the car from rolling away on a fairly steep driveway. I've attached a photo. Maybe it will help with an idea for your car.

Ted

[jagirs]

The Wilwood Caliper 120-12069 is physical quite large, how much room for it do you have?

[PeterAllen]

Originally Posted by jagirs

The Wilwood Caliper 120-12069 is physical quite large, how much room for it do you have?

As per post #21. It is doable, but a PITA regarding routing the cable around the strut, etc.

Ted, thanks. I earlier had a go at modifying lever ratios trying to obtain as much movement on the calliper actuation arm as possible.

[Bryan Wilson]

My Cobra has the standard Jag e brake that came with the rear end and it works well. Cannot move the car in either direction with the hand brake on

[Jac Mac]

Are these Willwoods of any use, made for Rally Cars like ford escort etc

[PeterAllen]

Thanks for the interest.

Bryan, I looked at the Jag callipers but I doubted they would fit under my rims. The beauty of the inboard rotor on the Jag is that you have a lot more space around them.

Jac, likewise I looked at those callipers but they have radial mounts which require a more complicated mounting bracket. If I were starting anew, and knowing what I know now, I would seriously consider them.

I'm really disappointed there are so many posts and advertisements commenting on the installation of the small Wilwood parking calliper but, unless prompted, nobody seemed willing to say they were a POS once installed.

I hate installing something I'm not happy with but I have to move on to other items or this thing will never get ready for registration.

[albanycobra]

They arent a POS, i have them on the back off my 40 they hold fine, passed all testing. trick is to allow them to float like brake caliper. Mine are mounted in a cradle of a pbr caliper with an adapter plate that bolts to the wilwood caliper and bolts to the pbr caliper cradle sliding pins.

[PeterAllen]

Any chance you could post a couple of photos of the set up. Thanks.