Right kids,

In the race car at the moment I currently have a hydraulic handbrake however I am not totally satisfied with it.

It is hooked up to the centre diff i.e. disconnects it when yoinked but it also seems to apply some braking force to the front wheels aswell hence making it rather hard to swing around predictably on dry bitumen.

Dont get me wrong. It is 100x better (and 10kg lighter) than the original set up but I was wondering if anyone knew how hard it would be to set up a second caliper on the rear end wholely and solely for the handbrake.

It would solve a lot of problems in terms of one way valves / pedal boxes etc.

The only downside that I can see is the extra weight of a couple of piss weak little calipers and also the engineering to get them to fit / work properly.

Any ideas?

Thanks

brendon

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Losing is worse than death. You have to live with losing....

Insert one way non return valves. its the way to go, it will save you a lot of time and messing around with having to install a second caliper.
They can be bought from any hydraulic hose shop. 1 hr job. cut hard lines insert, tighten up and bleed.

Stopping hydrualic pressure to front calipiers totally.

Would you care to explain how this is going to work?


Firstly, I don't believe that hydraulic pressure from your handbrake is getting to your front calipers Brendan. Has the system been split front/rear, or is it still diagonally split (as per standard WRX ie; LF & RR together, RF & LR together) with a dual cylinder handbrake?

The rear backing plate for the rear hubs that the calipers bolt onto? What if you get one custom made?

They are removable from the hub. So that shouldn't be too hard. Then you should be able to bolt 2 calipers onto the rear hubs.

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RS Liberty - Because WRX's are only good for parts...

From having a pretty rudimentary look at it, it look like they have plumbed it by running two braided hoses straight up to the rear caliper. This is why I think that as you pull the jigger whilst some of the fluid is exerting pressure onto the caliper some of the pressure is also going down to the front calipers / main brake fluid resivoir aswell.

Brendon

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Losing is worse than death. You have to live with losing....

This would have a couple of issues. either you would have to top up the master cylinder on the handbrake because there is no way of the fluid getting back into there or it would stop the rear brakes from working when you used the normal brake pedal. i.e. you press the pedal and the fronts work fine but the rears cant get any fluid.

Brendon

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Losing is worse than death. You have to live with losing....

I would think that they would work for the first shot, and then lock up as there would be no return.

If you put the one way into the handbrake line the problem would be that you pump fluid into the caliper but it would just go into the normal system because it could not return to the handbrake.

Next problem would be if you put the valve into the normal system between the front and rear brakes you would run out of fluid in the main master cylinder as every time you use the normal brakes the only place the fluid could go would be to the handbrake and overflow that.

Either way.....No Deal.

Brendon

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Losing is worse than death. You have to live with losing....

Like he^ says, forget one way valves. Your system will work if configured correctly for track or offroad use. System should be split from the master cylinder to:
- front brake cylinders
- rear -> hydraulic handbrake cylinder -> both rear brake cylinders

Note that modifying the braking system requires engineering approval for road vehicles

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A nation of sheep will beget a government of wolves.

I was busting out a few moves yesterday at home on the grass and it reminded me that when you are on the brakes and then yoink you can feel the handbrake pulsating through the brake pedal. Maybe I need to get someone to have a look at it?

Brendon

__________________
Losing is worse than death. You have to live with losing....