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Reading Your Corvette After a Long Storage

Technically Speaking

James Berry Mar 9, 2018
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Roy, last time we discussed the first part of your question about brake safety after long-term storage. We reviewed a few things that needed to be checked and replaced on your brake system before driving your vehicle. We also discussed replacing the single reservoir master cylinder with a dual reservoir master cylinder.

Now for the second part of your question. Here’s a portion of your letter to remind or catch up the readers.

Q: The car has not been operated these past 30 years. I had not planned for this so no long-term storage preparations were done. The car was running great with no problems at the time and has been in my basement garage, protected all these years. I’m running a Holley 4150 four-barrel and plan on sending it to Holley for refurbishment. I expected to find rust upon inspection of the gas tank; however, it appears that the gas tank has a coating inside. I would like some pointers on what preparations I need to undertake to get it back on the road. Any advice or comments would be greatly appreciated.

A: Roy, just like with the brakes there is a lot to consider and check after long-term storage. This is a slow and methodical process for safety reasons. I will go over some of the most common things you should look at but I would recommend having a professional mechanic take a look at the vehicle before taking it out on the road.

One of the best places to start before moving the vehicle is to look under the vehicle and inspect for leaks. Look for evidence of brake fluid leaks, gas leaks, power steering leaks, coolant system leaks, engine oil leaks, transmission fluid leaks, and rear axle leaks. If you check for this before moving the vehicle it can help you pinpoint exactly where the leak is coming from.

Fuel System
Roy, having the carburetor rebuilt is almost a must, due to varnish from sitting and especially since today’s fuels are not compatible with the old gaskets and seals.

Inspect the fuel tank, I would expect the fuel tank to have rust in it from moisture. For the price of a new fuel tank I would replace it if there is visible rust. The rust will give you a continual problem of clogging up the fuel filter. If any rust gets by the filter it could cause problems to your newly rebuilt carburetor.

Replace or rebuild the fuel pump. If it is not failing now it’s probably on its way out.


Replace all the rubber fuel lines and inspect the steel brake lines for rust. If the steel brake lines are excessively rusty they should be replaced. If you are using the old steel brake or fuel lines use compressed air to blow through the steel lines to remove any contaminants.

Hopefully when the car was parked and stored, the battery was removed. If the battery was left in the vehicle for an extended time, you will have a bigger job on your hands.

You will need to remove the old battery and check for evidence of any acid that may have leaked out. If there are any leaks, the acid can be neutralized with baking soda. Also check for any structural damage caused from the leaking acid. Check the battery cables for any corrosion and replace if necessary.

When you install a new battery keep in mind something could be shorted and could cause a fire. For example, rodents have been known to eat insulation off of the wiring. When you install the new battery, if you have a pop or a large spark the vehicle may have a short.

Never leave the battery hooked up if you are not with the vehicle for the first few weeks as there could be an underlying problem. This will also give you time to make sure all the electrical components are functioning properly.

Turn the Engine Over
Remove the spark plugs and squirt a bit of oil into each cylinder and let it sit overnight, I like to use Marvel Mystery Oil. In the morning, try to turn the engine over by hand using a socket and ratchet attached to the crankshaft bolt. If the engine does not want to move freely do not force it. There could be some rust in the cylinders or stuck piston rings causing the engine to freeze up.

On a manual transmission vehicle I have also seen the clutch plate stick to the flywheel. If this happens you will need to pry the clutch plate away from the flywheel. (Look for an upcoming article detailing how to free up a stuck engine.)

This would be a good time to replace the spark plugs, distributor cap, rotor button, spark plug wires, thermostat, points and condenser (if so equipped) and inspect all of the hoses for cracks or soft spots.

Replace All of the Fluids
If the vehicle has been sitting for years it will require all the fluids to be replaced. Besides the fluids being old, some fluids can absorb moisture, rendering them even less effective.

Prime the Oil Pump
Before trying to start the engine you will need to prime the oil pump. I prefer to remove the distributor and install an oil pump priming tool and spin the oil pump with a drill for several minutes. This will ensure oil is on all of the moving parts and no damage will be caused to the engine due to a dry start.


The oil pump on most Chevrolet engines has a slot in it that is driven by the distributor. The oil pump priming tool is simply a rod with a straight bit similar to a screwdriver with a sleeve over it. If you do not have the tool, you can remove the bottom gear off an old distributor and make a tool.

Check the Suspension
Inspect the suspension and look for worn or loose ball joints, deteriorated bushings, leaks at the shocks, and missing or broken hardware. Lube and grease the suspension.

Time to Start the Vehicle
When you start a vehicle for the first time in years the fuel will take about 30 seconds to fill the fuel line and prime the carburetor, during this cranking time oil is being pumped through the engine. If the engine does not start after about a minute stop cranking; you do not want to overheat the starter.

Take a few minutes to check for fuel. Look down the venturi of the carburetor, pump the accelerator and look for fuel spraying from the accelerator pump. Also, check for spark by removing a spark plug wire and using a spark tester to check for spark while cranking the engine.

Once the car starts, don’t rev the engine. Let it fast idle as normal to keep oil flowing through the engine. After the fast idle cycle let the engine idle and warm up normally. Make sure you are monitoring oil pressure during this process. If you have installed coolant keep an eye on the coolant level to drop when the thermostat opens. Once the thermostat opens top off the coolant. Also, make sure the alternator is charging.

After the thermostat opens and you have topped off the coolant shut off the vehicle and check for any leaks and top off the fluids. Check your running lights. With an assistant, activate the turn signals, headlights, brake lights and high beams to ensure they are functional.

A short test drive will give you a chance to listen for any rattles and engine misses while keeping an eye on the gauges for any abnormalities.

After running the vehicle for the first few hours, change the oil and the oil filter again. The reason for this is to make sure any rust or contaminants that may have broken loose during the running period have been removed.

Roy, I hope this helps answer some of your questions. Now it’s time to get that Corvette out of the garage and on the road again. Enjoy and happy driving. Vette

Photos by James Berry



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