A hydraulic hand brake allows you to use the normal brake pads in the rear calipers to lock the rear wheels to instigate a drift or handbrake turn.
This works by intercepting the front to rear hydraulic brake line and adding in a non assisted master cylinder.



The most common size of master cylinder used is a .625.

The type is actually a clutch master cylinder as these are non assisted and only have 1 output whereas a brake servo will normally have a minimum of 2 outputs. 1 front, 1 rear.


The first thing to do is work out which of the 4 lines running down the left hand side of the transmission tunnel is the rear brake line. From underneath the car, it is the line nearest to the out side of the car. It is also the smallest. If you are unsure then just trace the line towards the back of the car. It will enter a T piece which splits the pipes off to both sides of the car to feed each rear wheel.


Once you have identified your front to rear brake pipe, you need to cut into it. I would however recommend that you first fit the new hydraulic handbrake into the car so that you can work out where you need to cut the pipe.

So firstly, you need to mount the hydro.
I made a bracket that bolts through the side and top of transmission tunnel. As you can see, it is mounted so that the direction of pull is directly towards where I sit so that the forces acting on it are working in the right direction.
If you mount it parallel to the transmission tunnel then you're pulling it sideways so you're wasting effort and applying forces to it that it was never designed to take..




I am also lucky enough to be good friends with the guys at HEL hoses so got nice flexy's made up instead of using kunifer brake pipe.
Mine was bought from here OBP and cost about £75.
If you are planning on making your own hydro then FFS make it strong. If you don't then it'll bend and be completely useless and make you look like a dick in front of all the other drifters and they will point and laugh at your weak hydro game. You have been warned!!

Once you have your handbrake fitted into the car, you need to drill a hole through the transmission tunnel to allow you to pass the pipes through so that you can re-route the hydraulic fluid through your master cylinder in the car.

Use the Making brake pipes thread to form 2 lengths of pipe with male ends that will screw into your master cylinder.
Once you have the pipes fitted and tightened into the hydro in the car, you can go underneath and cut into the front the rear brake line.
You need to feed the pipe coming from the front of the car into the rear port of the master cylinder where the reservoir would be.

Port on the left of the below image.






The plumbing should basically be as below.




so now you need to cut intot eh front to rear line and use the making brake pipes thread again to put a female flare nut onto both ends of the front to rear line and then screw the lines running to and from the hydro into the front to rear line.

Then just bleed the rears and hey presto. You're done.
Well. If you have any type of pressure bleeding system then you're done. If not then you need to find a mate to help you bleed them.
The standard system of pressure on, open bleed valve, close bleed valve, pressure off is used but you have to pull the hydro as well.
So to bleed you need your mate sat in the drivers seat and you with a tube and a 7mm ring spanner.
Put the ring spanner over the bleed nipple and crack it off but don't undo it. Then put the tube over the bleed nipple and put the open end into a bottle.
Now open the bleed nipple and tell your mate to push down gently on the foot brake and once that is fully down, pull the hydro with his foot still on the pedal. Once pull brake and hydro are on, do up the bleed nipple and get mate to release pressure on both pedal and hydro.
Repeat this process until all that comes out of the bleed nipple is brake fluid. No bubbles no matter how small they are. Don't forget to keep topping up the brake fluid reservoir or you will be there all night!!

See here for another guide to bleeding hydro systems.



:edit:
Later E36's with ASC seem to have 2 front to rear lines that allows the computer to apply the brakes to different corners..
This will either need bridging so the ASC doesn't work anymore or using a twin M/cyl hydro like this one.





And here's a stolen diagram of how it should be plumbed...



borrowed from tramp drift