brake master cylinder and or front hub conversion?

[Piledriver]

Sorry, and thanks for posting a pic, I've been playing with my new toy.

I thought it was just a guide tube for the cable sheath?
It LOOKS like the parking brake cable AND sheath have to move to get even actuation.

I don't have full installation to look at, but the actuators must pull together evenly for proper operation, indicating the cable sheath probably floats some.
Admittedly this is only based on my looking at how the parts in front of me look like they should work.

On the arm I ground to fit, it took about 5 minutes to get a good fit.
There's gobs of steel there, no fear of hurting anything.

IIRC (and FWIW) 911/6s had this parking brake setup from the factory.

[Type 4 Unleashed]

The 911 setup is the least expensive but much more work, I would rather have a set of the 914 GT calipers to bolt on, but they've gotten way out of hand price wise.

[helowrench]

Sorry, and thanks for posting a pic, I've been playing with my new toy.

I thought it was just a guide tube for the cable sheath?
It LOOKS like the parking brake cable AND sheath have to move to get even actuation.

I don't have full installation to look at, but the actuators must pull together evenly for proper operation, indicating the cable sheath probably floats some.
Admittedly this is only based on my looking at how the parts in front of me look like they should work.

On the arm I ground to fit, it took about 5 minutes to get a good fit.
There's gobs of steel there, no fear of hurting anything.

IIRC (and FWIW) 911/6s had this parking brake setup from the factory.

Pile, do you have any way to weigh the entire assy, backing plate includeda?
I am in an argument with my engineer (Phil) about this.
Rob

[Piledriver]

I have a gram scale somewhere for doing pistons etc, I think I remember where it went, will look in AM.

But the whole setup is probably ~1% of the arm weight (ballpark#), even allowing for unsprung weight%.
Plus, good, light alloy calipers generally do not have built in parking brakes.
(I think we are all ears if you have a lock on some that do)

I'm going to make a WAG your engineer want's you to go with an inboard single parking disk?
He has a point, but it's a small one...
You can also get aluminum rotors... ceramic coated.. Might even hold up for that use.

I ran for years with no parking brake...

If your engineer is really concerned about unsprung weight, you can get fantastic forged 15X7 wheels at ~9 lbs.
You see similar on WRX etc, but they CAN be had in more bolt patterns.

Tubular arms can be had, but the wheel/tire combo weight overwhelms everything else.

[helowrench]

Nah, he is advocating using a Wilwood mechanical spot caliper for the parking brake.

I contend that if the entire backing plate and park brake assy weighs in at under 2 lb total, it is a nonissue.
(I agree that a little bit of research on the tires themselves will get that 2lb back or more.)

[Piledriver]

Nah, he is advocating using a Wilwood mechanical spot caliper for the parking brake.

I contend that if the entire backing plate and park brake assy weighs in at under 2 lb total, it is a nonissue.
(I agree that a little bit of research on the tires themselves will get that 2lb back or more.)

The spot caliper would make sense if it was mounted inboard on a CV.
(They make kits for that, or should)
Outboard it would end up weighing about the same and costing much more.
The drum backing plate is just thin stamped steel, a caliper mount needs to be pretty sturdy.

I would be mildly surprised if both sides together made it much past 1 lb...
The backing plates are only the size of the parking brake, the disc shields are separate.

I'm not counting the parking "brake drums", those are still required if you want to stop at all, as they are the ID of the discs.
I'll look for the scale in the AM to remove all doubt.

Aluminum or spun steel "hats" are also an option for serious weight and cost reduction.

IIRC Coleman Racing makes some interesting combos, it's been awhile since I looked at what they had.
(floating discs optional)
http://www.colemanracing.com/Brakes-C94.aspx

Note: Very Bad Website, causes Very Bad Ideas.

I'm seriously considering 911 lower A-arms and torsion bars and Coleman upper a-arms attached to cut down 911 struts.
(I got some rusty tubes from PA, but the spindles>down are fine.
(Not on the 914, on the T3 )

[Piledriver]

OK, I really suck at guessing weights from memory.

My scale only goes to 5 lbish, and one side weighs more, the shoes are heavy.

A trans mount parking brake would make the most sense, as it would have it's own tiny disc and add zero unsprung weight.

[helowrench]

Wow that much?
Mechanics always hate telling engineers they were right...

[Piledriver]

Wow that much?
Mechanics always hate telling engineers they were right...

Just tell him that if you are going to spend that kind of $$ you want no unsprung weight.


If you can find the small CV mount rotors cheap and fab your own bracket for the trans, it wouldn't even cost much.

[helowrench]

If you can find the small CV mount rotors cheap and fab your own bracket for the trans, it wouldn't even cost much.

Where do you find these guys?
I was just going to go looking for Kart discs.........

[Piledriver]

...Hmmm.

I just took another look at that scale and it only goes to 800g, the 5 lb thing I think assumes some additional weights that can be hung on the end of the beam that i don't have.

For context, they weigh about the same as 2L T4 rods, the context being how much ~a kilo will really matter at suspension motion velocity.

I'll google for CV mount brake discs for you.

Wilwood has them, or can make them, its probably just a kart or motorcycle rotor with a few CV patterns drilled in.