Rear disc conversion

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L6 - Race Bred
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Rear disc conversion

Post by el_jelly »

Rear disc conversion (Personally I haven’t done it yet but it is a good article anyway, posted a long time ago, somewhere)

A basic how-to for those who want to covert their drum brakes to rear disc brakes.

* You may not need everything but it's good to have!

* 90-93 Integra Rear Trailing Arms (with everything attached Rotor, Caliper, e-brake Cables...) or 90-91 CRX Rear Trailing Arms (with same...)
You can use either trailing arm but for CRX you need CRX e-brake cables and for Civic you need Integra e-brake cables (might as well get whole CRX trailing arm + cables for CRX, and whole Integra trailing arm + cables for Civic)
* 90-93 Integra "4040" Brake Proportioning Valve (Prop Valve), HIGHLY RECOMMENDED!!!
* New Rotors or resurface old ones.
* Reman. Calipers (if your old ones are in bad condition)
* Stainless Steel Braided Brake Lines.
* New Brake Fluid and Brake Pads.

1/4 and 3/8 Sockets (14mm and 17mm especially) and Wrenches
1/2 Breaker Bar (for getting tough bolts off)
Flare Nut Wrench aka Line Wrench (especially 10mm for the brake lines)
Box End Wrenches
Open End Wrenches
MAPP Gas Torch
Lithium Grease Gun
Jack (the bigger the better) + stands (4 will be good)
Dremel (rotary tool) with Gyros Super Tensile Cutting Discs
Rubber Hammer
PB Blaster
Metal Bristled Brush aka Battery Terminal Brush
Power Drill with good bits (I used Craftman 18v with Dewalt bits)
Torque Wrench (in FT-LBS)
Pliers (Needle Nose, but regular would work to)
Pry Bar
Gear Ratchet (works great for loosening e-brake cables)

Preparing the Trailing Arms.

Start the process by removing the calipers/brake lines from the trailing arms and then removing the rotors. Spray the whole thing down with PB Blaster to eat off the rust and then scrape everything with the metal bristle brush to scrape off the rust and dirt especially around the wheel bearing. One problem is that the e-brake cable attachment is attached to the caliper and after years of sitting it locks up badly (making it impossible to remove the caliper from the cables). The original design was of a bolt and pin design, the bolt goes between the cable fork and the caliper, and the pin makes sure it doesn't fall off.

Now if you don't have this problem at all you can skip this step (but I would still recommend taking off the bolt/pin and replace). Take the drill and drill out the bolt going from small bit to the largest needed to drill out the whole bolt. I also took the Dremel with cutting disc and made cuts between the fork and caliper bracket so that they wouldn't touch as close and wouldn't rust together in the future. Once you have finally separated the caliper from the e-brake cables you can either replace the calipers (if yours weren't in good condition such as broken seals for the cylinder, you should buy a new remanufactured caliper) or use your old ones if they are in good shape.

Now with everything in good shape you can assemble everything back together. At this time you can bolt the brake lines to the mounts but don't attach them to the caliper yet.

Removing / Installing Trailing Arms.

The actual removal and installation of everything is pretty straightforward and simple, it's just very time consuming and a lot of work. Prepare for downtime. If you need your car for anything important be prepared as there can always be unexpected delays.

First step is to remove your center console so you have access to you e-brake cables. Use a wrench and turn the nut until it comes completely off the long threaded post. You can use a normal 12mm wrench to loosen the e-brake cables but a Gear Ratchet works wonders...

With those cables release they are now free for you to pull out from below the car later on. Now comes the more difficult part. Jack up the car and support it with jack stands. You might want to jack it up on each side and use 4 stands that way you will have more room underneath to work on the car. With the car supported and the wheels off climb under the car to where you see the edge of the gas tank closest to the front of the car. Remove the heat shield there (right above the exhaust), it is held on with 4 bolts. You may want to remove the exhaust to make it easier to work. With the heat shield removed you have now exposed the plate with a rubber grommet where the e-brake cables are going into. Now you might want to remove the 4 bolts that hold the cables to the chassis (2 for each cable). The left side cable's bolts are pretty easy to get to so undo those. Next you will want to do the other side. This is the hardest part of the whole thing. One of the bolts is about half way hidden behind the gas tank. So now you have a few options. If you are somehow able to bend the lip on the gas tank you could have good access to this bolt. However without a lift this is very hard. So while you are under the car you can't go that far. So what I did was use a dremel and cut off the metal around the bolt. There is about a 1'' lip on the tank, so don't think you are cutting right into your tank or anything. Hack away the metal around the bolt until you are able to fit a wrench up there. Use the flare nut wrench if you can because you really don't want to chance stripping this bolt. So once you have cut enough off then remove the 2 bolts holding that cable. Now you can get out from under the car and move onto the Trailing Arms.

The trailing arm removal/installation is the easiest part since it's exposed and you don't have to crawl under anything. It's pretty self explanatory, there are 5 bolts holding on the trailing arm. One bolt at the Upper Control Arm to Trailing Arm (we'll call it TA), another at the Lower Control Arm to the TA, 2 bolts at the TA bushing, and one at the compensator arm to the TA. When removing the bolt from the compensator arm to the TA only undo the bolt that holds the Compensator Arm to the TA, not the bolt that holds the arm to the chassis because that controls the Toe for your alignment and unless you plan on getting an alignment then don't unbolt that. One other thing is while you are down there you might as well (if you already haven't) place some Grade 8 washers (very strong washers that won't compress) behind the Upper Control Arm Bushing and that will correct your camber (if your car is lowered and you have too much negative camber). The rule is 1 washer for every inch lowered. So one inch lowered = 1 washer. For cars lowered to the half you just round up so it would be 2 washers for a 1.5'' drop.

If you are having trouble getting the bolts for the trailing arm off then here are a few tips for you. First you can use your MAAP Gas Torch to heat up he bolts. Hold the torch at the bolt head until you start to see the bushing near it smoke. However let it burn a little bit, yes I said let it burn, but not too much that it catches fire. The burning will separate the bushing from the bolt which it has frozen on to. Now spray the whole thing down with PB Blaster and watch as lovely white smoke comes from the bolt. Once it has cooled enough that the PB Blaster doesn't evaporate right away put your 1/2 (or larger) breaker bar onto it and turn the correct direction. This should get the bolt off with ease. With the trailing arm off you can undo the brake lines to the chassis. Use the 10mm Flare Nut wrench and remove the rubber line from the hard line. Now there is a clip which you pull out towards you and that will free the line from the bracket (leave the clip on until after you disconnect the line because it keeps the line from twisting when you try to take that nut off). Now brake fluid is going to drip down, you can place a pan under it or use a rag at the hard line or however you want to do it.

Now you can install your new Trailing Arms. Do it just the same as you did to remove it. Make sure you torque those bolts down to spec.

With the Trailing Arms installed you can attach the new brake lines. Attach it at the caliper first and make sure it is positioned right and there is enough slack. Make sure to use new washers (all new hardware is supplied with SS lines). Now attach the new line to the hard line and make sure to put the clip back in to hold everything in place. If you bought SS lines you will want to replace the front lines now also. Once that is over the majority of the work is done.

The next step is to decide whether or not you want to install the prop valve. You don't need to do this but I highly recommend you do. So if you still have plenty of time then you might as well install the prop valve now (since you have to bleed the brakes now anyway). The prop valve is located on the right side of the engine on the fire wall. I say the prop valve sort of resembles a spider. It is hidden sort of under a bunch of wires for your engine harness. The prop valve is a bitch to take on and off. You will need to use the 10mm flare nut wrench to get the fittings off. They are exactly the same as the fittings for the hard line for your brake lines. However the lines to the prop valve aren't flexible as they are made of copper. They can be bent but you will need to bend and align them back to get them to screw in right. All I can say for this is remove everything in the way (strut bars, intake hoses, wires, etc...) and then remove the lines from the top outside to top inside and downward the same way, and install them just as you removed them. The less you have to bend them the easier it will be to install the new one.

After the prop valve is installed you can put everything back the way it was. Now is the time you bleed the brakes since you now will have a lot of air in it.

*Additional recommendations for this swap:
Last edited by el_jelly on Sun Nov 18, 2007 9:42 am, edited 1 time in total.
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