The brake system needs to...
The brake system needs to be inspected and rebuilt in its entirety. That means all seals, pads, flexible lines, fluid, damaged steel lines, etc., will need to be fixed or replaced. If your rotors are excessively cracked or worn too thin, inquire as to the latest technology for these items from your brake manufacturer. Rotor failure is always serious.
Inspect the engine mounts, front hoop tubing, upper control arm mounts, and any areas where fatigue might have caused cracking or breaking of the metal. Once all of the inspections have been done and all repairs have been made, it might be a good idea to paint the front clip. If you plan on doing a complete repaint of the car's frame, do the rest of the inspection first.
Make sure you inspect the components for the rear suspension too. The heim joints, shock brackets, pull bars, lift arms, and other devices need to be checked out, cleaned and serviced.
3. Driveline Assembly - Inspect the entire driveline. If the driveshaft is not damaged, then just remove and replace the U-joints. This should be done at least once a season. These parts are subject to high stress and are too cheap to take a chance on failure.
Inspect the yokes and transmission tailshaft to make sure everything is all right. Now, there are high performance shafts and yokes available that weren't a few years ago. If you are looking for a little more performance and reliability, check out some of the new stuff.
Go through your cooling system...
Go through your cooling system and check for corrosion, cracks in the radiator, old hoses, worn belts and leaking water pumps. If your belts and hoses have not been replaced lately, do it now. A failure later on will most likely cost much more.
The rearend should be removed, and all mounts cleaned and inspected. Replace all grease seals, axle bearings, and pinion bearings where necessary. Check the axle tubes for damage and to see if they are straight. Shock brackets and trailing arm brackets need to be inspected for damage or wear. All heim joints should be looked at and replaced if worn excessively.
Look over the panhard bar mounting brackets to see if they are bent or cracked. These mounts take a beating, especially when small hits are experienced during a race. Not much attention is paid after the race, but we can all remember incidental contact that was made that might have caused some damage.
4. The Brake and Clutch Hydraulic Systems - The brake system should be completely gone through at the end of the season. Remove the brake and clutch master cylinders, inspect and flush the lines and do a rebuild of the cylinders. The last thing you need is brake failure, or clutch failure for that matter.
Check to make sure your alternator...
Check to make sure your alternator is charging correctly and that the bushings are not worn. Now is a good time to check the belts for proper alignment with all of the pulleys.
If your brake lines have been banged up or otherwise damaged, you might consider a replacement while the car is apart. At least replace the flex lines which may contain degradable synthetic hose inside the woven stainless steel.
Look over the clutch and brake pedal bushings and replace if worn where there is excess play. Look over the brake adjuster and clean and lubricate the cable.
If you don't think your brake bias was totally correct during the past season, now is a good time to rethink the master cylinder and caliper sizes. Adjusting these components can bring your brake bias into a more balanced state. Your brake adjuster is only intended to be used for fine tuning the bias.
Check all of your wiring to...
Check all of your wiring to detect worn or frayed wires. Where the wires pass through the firewall or other partitions are areas of concern. Replace the rubber grommets and wiring if necessary. You want to feel comfortably sure that a short will not ruin a good night of racing.
5. Cooling System - During the past season, the radiator may have suffered collisions, beating and banging or just nicks and scrapes from working on the car. It needs to be pressure tested and inspected thoroughly to make sure it will perform for another year.
Replace hoses, belts, pressure caps and anything else that might give you problems at the worst time, like when leading a race. Nothing is more frustrating than those little annoyances such as a water leak or a thrown water pump belt.
6. Wiring and Switches - To ensure your car doesn't stop running at the wrong moment, all wiring and switches must be fresh and free of corrosion. The vibrations that go on during a race can cause the wire connections to break or come loose. Wiring is fairly simple stuff and it would make good sense to have someone rewire the entire car during the off season.
Recheck the grommets where the wires pass through the firewall or other panels. Cycle the switches and notice if they feel tight or corroded. Replace the ones that are suspect. Many races have been lost due to a cheap switch or connector.