Disc Brakes





DISC BRAKES & Semi-Floating 14 Bolt Installations

Well let’s start with this. The axle was from a 1993 Chevrolet C2500 Chassis. The axle was 6lug, and had 3.73:1 ratio in it. This worked out great, my truck currently had 3.73:1 running gear. With this axle, I wouldn't have to run out and re-gear just to drive in four-wheel drive. Granted I am planning on a gear swap to 4.56:1 and switching to 35's. The axle was picked up at the local salvage yard for $350. I had to pull the axle from the chassis, but the truck had been involved in a fire, the bed had already been removed. So, with this in mind, I grabbed the axle, spring bolts and mounting plates, and brake lines. Oh, I snagged the drive shaft too, just don't tell them!

This is the rear end after I got it home. Fist thing I did, was cleaned it up, opened up the case and inspected all the items inside. I knew even before buying the rear end that it was in a flood area. The axle had been under water for about 2weeks. This was the main item I was worried about. The salvage yard said they wouldn't offer a warranty because of the price I wanted to pay vs. the price they wanted. The salvage yard said they usually got around $1000 for this axle.

Here are the axles, studs and the backing plates. The Drums have been removed for inspection. It was about this time I decided that I wanted to put disc brakes on this rear end. After doing my research I decided on a Disc Kit from TSM. The TSM kit uses the rotors from the front of a 2wd Blazer, and either Calipers from a Monty Carlo (No Parking Brake) or Cadillac Eldorado Calipers (With Parking Brake). I first used the Caddy calipers due to the NC. Requirement for a parking brake. I later changed to the Monty Carlo calipers. They are self-adjusting, and seem to work worlds better then the Caddy calipers. Plus they are much less expensive. One thing to consider while you are at the salvage yard, pick up some calipers from a junk car for the core charge. The core charge for the Caddy calipers was $80 EA! This photo also depicts step one of the Disc Swap. You need to remove the Drums to get the entire project started. Keep in mind; this application is already off the vehicle. You can do a conversion on the vehicle, and will require some different steps. Plan accordingly.

This photo shows the housing. When the picture was taken the axle was upside down. I just flipped the photo over. Don't laugh. In this photo, you can see the bolt pattern, and design of the housing and differential cover.

The Semi-floating 14 is quite a bit different then the full floating 14. This axle is lighter, the ring gear and pinion are smaller, and most importantly the axles are C-clip design. This means, that if you break an axle shaft, you can't drive the vehicle. A full floating design, you can still drive the vehicle. There is one thing that I haven't tried, and would only do in an emergency. I figure that the brake hardware would hold the rear axle in if the truck had to be driven with a broken axle shaft. I haven't tried it, and nor do I plan to. I'm sure that this axle will hold up well with the 35's I'm planning and the Detroit I hope to put in the rear. Please note. For some reason GM uses Permatex gasket material on the new rear ends. I opted just to use a replacement paper gasket. You can see the Orange in this picture and the next few.

Step 2 for the Disc Brake conversion is to remove the backing plates. This will include removing the drum/brake hardware, axles, and brake lines. In this photo you can see where I’m using a line wrench to remove the brake lines from the backing plate. Also, observe the spring pad in the bottom of the picture. Yet another item that will play a part later.

Before you can remove the Axle shafts, you will have to do some work on the Carrier. You need to remove the "Cross Shaft Set Pin” This "Pin" is actually a bolt. In needs to be removed from the carrier, this then allows the cross shaft to be removed and the spider gears removed also. After removing these parts, you have the center of the carrier available to assist in removal of the Axle Shafts. One note: The Set Pin is often broke. I don't know if there is a special way or not to remove this with out breaking it. I guess I was lucky. But be sure you are very careful when removing this bolt.

In this photo you will observe the actual removal of the "C-clip) on the axle. After you get the cover removed, and the center pin removed from the carrier in the rear end, you will need to push the axle in. You can do this from where the wheel bolts on to the axle. The C-clip can actually just fall out; I opted to use a magnet to retrieve the C-clip. Ensure you keep all the parts you remove from the rear end. I marked each part to ensure it went back in its original location.

When removing the axle shaft, ensure that you don't drop, ding or damage any of the machined surfaces. There are parts that seals seat on, and parts that the axle rides on bearings. It’s important that these surfaces are not damaged. Take care to ensure the safety of these parts.

In this photo, you can observe the actual C-Clip. The C-clip seats in the little groove at the very top of the axle. The area above the Splines. This photo also shows the splines on the axle shaft. The weakest part of any C-clip axle is the area where the C-clip seats on the axle. If this area breaks, it allows the axle to slide out of the housing. I propose that the brake hardware would hold the axle in the housing under light use. An example of this would be driving home at a moderate speed and a short distance. It is possible that damage could occur to the backing plates, rotors and calipers. If you try it, let me know how it works ;)

Ahhh Yes... Air tools are a great thing. I couldn't believe just how tight these bolts were attached to the backing plate. I do suppose that they do play an important role in the life of the braking system. With out these bolts, when you applied the brakes, the backing plate would rotate until the brake lines failed, thus loosing rear breaks completely. Using the impact wrench I removed all 8 bolts (4 each side) and was able to remove the backing plate thus removing the remaining part of the evil drum set up.

These are the removed backing plates and bolts. These were in very poor looking condition when I first removed them. This was because of the flood that they were in. After removing the drums I had pressure washed the entire rear axle. This helped in checking out what I had in the first place. Plus, it was a great help in tearing down the parts. After the parts were washed off and dried, the rear end looked better and better. All in all, I'd say I stole it!

After going to the parts store and shelling out $180 just for core charges, I decided that there had to be a better way. I opted going the salvage yard route. I purchased 2 used calipers. This had the mounting pins, parking brake adj. lever and return spring. Even the new ones did not have these parts. I only paid $10 each for the core, which in turn saved me $140 in core charges. Plus when you factor in the additional parts that I saved money on, it was a good investment over all. Just as a side note for now, I later decided to change to Monty Carlo Calipers. These work worlds better then the Eldorado calipers.

Here are the New Calipers, Old Calipers and the packaging for the new calipers. I suggest that you make sure you are getting the proper calipers. There are a few different models that are available on the Cadillac’s. Ensure that the ones you are getting will bolt up to the backing plates, and match the mounting hardware as well as brake hardware. If you purchase the brake lines from TSM, ensure that the "Banjo Bolts" fit also. Also take a second to note the way that the hardware is installed on the brakes. Be sure you don't rotate the parking brake lever with out something to stop the piston. You hand doesn't count!

If you opt to use a S/F 14, or are reading this to see what problems and issues you have to work out with a S/F 14 install, here is an interesting item on the rear end that I used. It seems that this rear end had 2 sets of spring pads on each side. They both have to be removed. The spring pads that you will end up using are the ones with the hole in it, close to the axle tube end. Both perches need to be removed and repositioned. The position will be aprox. right in the middle of where the 2 were before. Use care not to damage the spring perches. I had a heck of a time trying to find the spring perches for this axle tube size. They are over 3". I don't know the exact size though. For those that decide to make their own perches, check out: Custom Perches . Glenn Viveiros is quite the handy man when it comes to custom fabricated top-notch items on these trucks.

Here is the initial build up of the S/F 14 & Disc Conversion. Little did I know that I was going to have to tear every thing down shortly. I determined later that the parking brakes were not going to operate properly in this position. Make sure when you start installing everything that you have the items in the position that will work best for the brakes you decide to use, and will allow you to run your brake lines in the proper manner. I wanted my brake lines ran on top of the axle tube, and have the flex lines tight against the tube. This took a little guesswork. But I'm happy with the way my brakes are currently. TSM made a suggestion, but I have no idea, nor have I found a source on the Internet that says that any position is better than any other. I suggest a high location to keep as much dirt out as you can, and most importantly a position to keep the lines out of harms way.

Next you will need to reverse the disassembly process to start reassembling the rear end. Make sure all the items are torqued to specs, and nothing seems out of place. You have already made sure that you will be able to run your lines in the correct method. I opted to replace the axle seals. I had toyed with the idea of changing the bearings, but money was an issue. I figured that if I needed to, that would be different. I washed them out well with a degreaser, and relubed them before reinstalling them. I wanted to make sure that any water and dirt was removed before putting them back in.

As with all brake jobs, you want to make sure that you keep all the components as grease free as you can. Also, now this may or may not be something that you agree with. I've learned long ago from a little hole in the wall shop I worked for. All drums and rotors need to be trued with any quality brake job. Most will argue that a new rotor IS true. Well I have always opted to have my new rotors turned. And every time, they were off. Quite a few times when buying new rotors from AutoZone and I asked the counter person to turn them also. They did everything but call me an idiot. Well screw them. It’s your money. Just a little plug for me, I've never been wrong with this issue.

In this photo and the next, all the hardware with the exception of the brake pads and the brake lines were installed to ensure that the equipment would mount together properly. One thing that had not been mentioned as of yet was that the axles were needed to be taken to be machined. The axle flange where the wheel bolts to the axle was about 1/16 larger than the inside of the rotor. I opted to have the axle machined so that when the rotors need to be replaced I won't have to keep milling them. The only problem with this setup is if a axle should snap, I would be hard pressed to find another on the trail. The manufacture of the rear end suggests removing the wheel with the axle installed. Using a grinder with the rear end in gear, grind the lip down to a point that the rotor will fit. In a dire circumstance, this would work.

In these next photos you will see different angles. As you can see, all the issues have been worked out. All the equipment is aligned perfectly. Reassembly of the rear end is almost complete. All angles were inspected before installing the remaining hard ware. Each step was taken small to ensure that everything would work with out any binding of the system.

A small problem was identified after installing the brake pads and trying, stressing TRYING to install the calipers. The mounting hardware wasn't large enough to allow the calipers to move on the backing plates. As a matter of fact I was on the verge of having to force the caliper pins into the backing plates. I opted to grind the backing plates to allow the pads to fit properly. Just a small step, and in convience. Nothing really note worthy. Just pointing it out.

Here is the small amount that was ground off the backing plate. You can see that there was only about 1/16 or so removed. You may or may not have the same problem that I had, but this will at least allow you to see what was required to allow the rear ends brakes to work properly. Always ensure that you have no binding in the system. This is the best time to check. You can remove the brake calipers very quickly right now, later you will have brake lines ran, and other issues to contend with.

Although there aren't any more pictures posted yet, I'll give you a brief rundown of all the rest of the steps. After you get all the brake hardware installed and ensure that all the components will work properly, you need to run your brake lines. Start from the middle at the drop down flex line. Measure the distance from the Center, along the top of the housing to where you want the termination point to be. TSM supplied me with a set of anchor points for the steel & Flex lines. These need to be welded to the axle tube. Don't do this until your are sure exactly where you want the lines at. I opted to purchase longer lines then what I needed. I bent them to exactly where I wanted them to end and used a Craftsmen Double Flare tool to put the fittings back on. This gave me the exact length of line I needed. I installed all the rest of the lines to the calipers, and prepared for the installation of the rear end. When you are going to install the rear end you need to be prepared. Measure pinion angle. This will be important when you go to re weld the new rear end. Next you need to have the rear of the truck supported by jack stands. Remove the rear drive shaft, parking brake cable, and the drop down flex line. Remove it from the axle; don't remove it from the truck. After you get the old axle out of the way, position the new axle under the springs. Take into consideration that the perches are not welded on. I raised the rear end into position, and measured from the springs to the backing plate. When these measurements are correct on each side, the rear end is centered in the vehicle. Bolt the rear end to the springs. After the rear end is secured, put your tires back on the axle. After this is completed, lower the truck back down on its tires and measure/correct the pinion angle. Re check the distance between the springs and the backing plate, and the pinion one more time. At this point you can either weld the perches, or continue with the brakes. I would suggest the welding of the perches. You don't want to get the brakes all plumbed and have the rear end tilt on you destroying your brake lines. Ensure your pinion angle is correct and begin welding. When you are welding the perches, do short welds. And don’t do all one side then the other. Take turns on different sides of the axle housing, and allow the rear end to cool between welds. If you over heat the tube, you can warp the housing rendering it useless. After all your welds are complete, continue with the brake lines. This is one of the easiest parts of the entire process. Just get the lines where you want them, and make sure they are secure. Weld on the anchor point for the lines, and connect the body’s flex line to the brake lines on the rear end. Open the bleeder screw on the caliper, and go about bleeding the lines as you normally would. When I was bleeding my caliper, I decided to use a C-clamp and bleed them off the rotor. This would allow me to make sure the bleeder was at the highest point, and I could tap the caliper making sure all the air was out of the system. This did require me putting the truck back on jack stands, and removing the tires again. Notes: When I first did the install I used Caddy calipers. I was not pleased with this setup from the start. I made sure completely that all the air was out of the lines. The calipers would work great for about 20-40 stops. Then the pads would start to wear down a little. The calipers were not self-adjusting, thus the pads had further to travel to make contact with the rotors. For whatever reason, I was not ever able to work this problem out to my satisfaction. I opted for the Monty Carlo calipers. These cost about $20 each (Much less than the others) and work so much better that I can barely describe it. I don't have a problem with the truck locking up the rear end with normal braking, but if I want it to, it will. I would like to mention that the system seems very well matched. I did some brake tests, and the truck would usually lock up all 4 tires at the same time. Keep in mind I'm running 33 12.5 15's BFG M/T's. I’ve found that this truck feels like it will out break a 1998 Mitsubishi Eclipse w/disc brakes. I also have a strong sense that this vehicle would perform flawless if needed to in an emergency. I'm currently considering a Hydro Boost system out of a diesel GM. Why? Why not. I need to change most of the parts incorporated with the system anyway. I think that this would add to the systems integrity. U-joint. I had to purchase a special U-joint. This has 2 different size crosses. One is a 1330 and the other is 1350. I paid about $25 for my U-joint. No drive shaft or rear end modification was required because of this. The 10bolt rear end uses a smaller U-joint. The 1330 would fit in the 10bolt. Best of luck. If you have any questions, please feel free to contact me about this setup.