I have a 1993 Honda Civic DX 4 door automatic and I want to change the rear drum brakes to discs, is there a way to do this maybe by getting the rear discs off of another civic of the same year?
Rear drum to disc swap?
First you need to acquire a set of EP3 discs. EL discs for Canadians also will work. The more complete you can buy, the better, low miles is good too. If you build them, which I advise against because its expensive, you need knuckles, the hub and bearings, caliper assembly, wheel sensors and all the bracketry. Regardless, you need Si brake lines and EP3 or DC5 ebrake cables. I believe non abs cars will require a new proportioning valve although I can't confirm this. EX models don't need one, the ABS takes care of it.
Start by doing normal rear end work proceedures, jack the car, stands, pull the wheels.
You don't need too many tools, 10, 12, 14, 17 and 19mm sockets, a couple other basic tools. If you have ratcheting wrenches, they will come in handy, there's some tight spots.
First, remove the brake lines from the drums. Its up on the wheel well, you'll also need to remove the brake line bracket and save it for the new lines.
Next go into the car and remove the console. Disconnect the e-brake cables from the handle. You'll need to rotate the carrier until the wire comes up out of the slot on the side, then the pin will come out the top. Unbolt the 3 bolts that hold the cable to the underside of the car.
Then you'll need to remove the wheel sensor wires. On the right side, the plug is in the trunk. Pull up the carpet, you'll see a silver cover on the right side, just behind the seats. Pry it up to reveal the connector, unplug it and push it through the hole in the floor. There's also a bracket that holds it under the car, and one that holds it to the UCA. It also helps to undo the bolt that holds the muffler guard in place so you can see what you're doing when you go to put the new one in. Its the guard bolt right next to the sensor bracket. On the left, the harness is above the gas filler neck. Its a tight squeeze, but you can grab it.
With all the connections undone you can now unbolt the knuckle. First, mark the alignment cam so you know where to put it back later. The back bolt on the bottom of the knuckle is eccentric. If you look at it, there's marks on it... mark the one that lines up with the mark on the frame, or use a marker to mark where it goes.
(the red mark in the picture isn't exactly right, but if you look at the cam bolt next to it you'll see the marks I'm referring to)
Using a jack to support the knuckle, remove the UCA bolt first, then the alignment locknut. Once you've got the alignment nut off remove the front lower bolt. The knuckle should swing down now. With a small hammer or a socket handle, knock the alignment cam out. You should have the cam bolt and the big slotted nut. the knuckle should be loose, remove it.
Remove the stock wheel sensor from the drum. Its the oblong shaped thing in on the back that the orange plug is attached to. Remove the bolt then pry it out carefully. You'll need to do the same for the ones on the discs. Put the stock ones from the drums in the discs. Bolt them back in, toss the Si ones.
Everything else is just in reverse order. If you need to install brake lines on the discs, do it beforehand, make sure you use crushwashers with the new lines to prevent leaks. You can also change pads and/or rotors beforehand.
Bolt the lower front bolt in, but not all the way. If you tighten it you won't get the cam back in. Then reinstall the cam, lining up the marks. Install the locknut and keep your marks lined up. Torque the locknut to 43 ft-lbs. Tighten down the front bolt now, also 43 ft-lbs. Then swing the knuckle up and install the UCA bolt. 43 again.
Install the bracket on the brake line with the clip and connect the lines. Bolt the bracket back on the wheel well. No spec... just tight.
Feed the E-brake lines in through the floor. Connect them to the carrier attached to the handle and rebolt them to the floor pan. Don't forget to install the rubber floor seals.
The E-brake on the caliper is the sprung hook on top. Feed the line under the knuckle and through the hole in the bracket, then push the spring down and connect the line. The right side goes on pretty easily, the left is very tight. I found its easier to install if you connect the lines to the caliper first, then connect them to the handle. To connect them to the handle, loosen the adjustment nut as much as possible. Connect the LEFT cable FIRST, then rotate the carrier and connect the right cable.
Reconnect the wheel sensor wires and bolt the brackets down. Test the ebrakes to see if they're engaging by rotating the hub with the handle pulled. If they don't engage, tighten the nut above the carrier until they grab.
Then pump the brakes a couple times to partially fill the new brake lines, you'll need to thoroughly bleed the whole system.
Go gentle on them at first just to make sure everything is ok, and gradually get harder on them... they should work just fine. If you want to make sure they're engaging, use a marker and draw lines on the rotor.... they should be gone once you drive the car.
Estimated time to complete 3-5 hours
Have at it.
If you're real hardcore and you want to have the calipers pressure tested... the line pressure is about 770 psi to the fronts, 170 psi to the rear. This is the EX w/ ABS. I don't know how different the LX/DX proportioning is.
Rear drum to disc swap?
You'll need a 4 wheel disc master cylinder at a minimum. The MC on your car now won't hold enough to power rear discs. Disc brakes require more fluid to move than drum cylinders.
