I have completed the upgrade to 4-wheel power disc brakes. I have, however, chosen to defer installing the power brake booster so I have open space for working on the steering and fuel pump. More on those projects later.
The Lift
Before getting into the brake modification, a word about a very important tool. I have had a 4-post lift in my back yard for a few years now. This is mainly used for storage. I normally keep the 56 Thunderbird on the lift with the 60 Rolls Royce underneath. While working on cars, this storage tool doubles as an excellent repair tool.
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Figure 1 - 1956 Thunderbird on 4-post lift |
Using my lift, shown above, makes major upgrades MUCH easier. While it is possible to upgrade the brakes without the lift, I am simultaneously upgrading the steering to rack-and-pinion. The steering upgrade almost requires a lift. If you are doing this kind of work and have the space, consider getting a lift. I paid about $2200 for the lift, delivery, and installation. It has been well worth the cost.
The Kit
I purchased the Kit from http://www.thunderbirdbrakeparts.com for $1600. I liked the fact that the kit did not require changing the front spindles so alignment or suspension would not be affected. Here is a picture of the complete kit from their website:
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Figure 2 - ThunderBrakeParts.com 56 Tbird kit |
Front Brakes
The front brake kit retains the original 1956 drum brake spindles. This makes it easy if I, or a future owner, ever want to go back to the original drums.
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Figure 3 - Front Disc Brake Kit |
Figure 3 shows one wheel components for the front disc kit. Included are the rotor, caliper, wheel bearings, spindle adapter, and hardware. The kit is complete. I did not need any additional items other then bearing grease.
Shown in figure 4 is the front left wheel before removing the drum unit.
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Figure 4 - Front Drum Brake |
Once the wheel is removed, the drum is accessed by removing the wheel nut and pulling the drum and bearing unit.
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Figure 5 - Hub Removed |
Once the drum and bearing are removed, the next step is removing the brake components themselves. Fortunately, this is quite easy. After disconnecting the brake line from the slave cylinder, four bolts hold the brake unit to the spindle. Remove those and the brake unit is removed in one piece.
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Figure 6 - Before cleaning
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Figure 7 - After cleaning |
Using a putty knife, brushes, and solvents, the war on grease is finally won. Figure 7 shows the same fitting much cleaner. It is not concourse, but at least is is no longer an embarrassment.
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Figure 8 - Cleaned spindle ready for disc brake |
The spindle is now ready for the adapter, rotor, and calipers. Once the bearing are packed with grease, all components bolt together easily.
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Figure 9 - Completed front disc |
The completed unit is shown in figure 9. The red seen on the outside of the disc brake shoe (inside the caliper) is a formula called "disc brake quiet". It minimizes the squeal sometimes caused when the brakes are lightly applied. It can me found at most auto parts stores.
Rear Brakes
The rear brakes are not as important as the front on any car. The front brakes do 80% of the stopping force. On the Thunderbird, it is possible to leave the rear as drum units with little change in stopping power. Disc brakes require more brake fluid in the slave cylinders to stop, so a proportioning valve must be used to ensure the front discs receive enough brake fluid by restricting the flow to the rear drums. Rather then dealing with the proportioning valve, I chose the more elegant approach, install discs in the rear as well.
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Figure 10 - Rear Disc Kit (Caliper, Rotor,Adapter) |
The rear kit contains the same basic parts as the front kit. It is not as complete as the front kit. There is no adapter components for connecting the parking brake cable. The existing cable will not work without extensive modifications. Because the Thunderbird contains a live axle, the axle must be removed to bolt the adapter to the axle housing. This is easier then it sounds. I did, however, have to spend several hours grinding the adapter to fit the axle housing. Be prepared to make some "adjustments" if parts do not fit quite right.
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Figure 11 - Rear Brake Drum |
The rear drums simply slide off after the wheel is removed. They are held in place by only the wheel lug nuts.
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Figure 12 - Drum removed exposing Brake Shoes |
Once the drum is removed the axle is unbolted using the same 4 bolts holding the brake unit in place. First dis-connect the brake line from the slave cylinder and remove the parking brake cable. Dealing with the parking brake cable is actually one of the hardest parts of the conversion. The clips holding the original cable in place were rusted and would not budge. They were not accessible enough to cut. I just had to keep working them until they finally released the cable. The new calipers do not use the same clips or cable as the old units. There is no provisions in the kit for connecting the parking brake, although the disc brake calipers support a parking brake cable. You are on your own to get this properly connected. I bought a universal parking brake cable kit from eBay for about $80.
Figure 13 - Brake unit and axle removed |
Once all components are removed, you are left with only the axle housing, as shown in Figure 13. At this point, make sure you test-fit everything and make adjustments as required. I spend several hours grinding part of the adapter plate to make it fit snugly against the flange on the axle housing. Spend the time to make a quality fit, as you do not want any part of your braking system to fail due to taking short cuts!
Figure 14 - Test fit rear brake caliper adapter |
Once the adapter is in place, test fit the components again without and with the rotor in place. Again, minor adjustments might have to be made.
Figure 15 - Rear Disc Complete |
It is finally done! The master cylinder and brake booster will also be replaced, but I chose to remove the old unit and wait to replace the new unit since the removal of the old booster opens a lot of space in the engine compartment for other projects. I will work on these other projcts before installing the new booster and master cylinder.
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