1981 Chevrolet Corvette - Page 4 - Answered Questions & Fixed issues

If it is necessary to remove the heater assembly, the cooling system must be drained before removing the heater core.
When a heater core leaks, a new heater core is installed or the old one repaired.
Heater Housing

• The heater housing is usually under the dash and must be removed to gain access to the heater core.
• Procedures for replacing the heater core vary with the year, make, and model of car. It threfore necessary to consult the manufacturer's repair manuals for the proper procedure for replacement.

The heater housing is disassembled to get to the heater core. Heater Core

• Remove the access panels(s) or the split heater/air conditioning case to gain acess to the heater core.
• Remove the heater coolant hoses.
• Remove the cable and/or vacuum control lines (if equipped).
• Remove the heater core securing brackets and/or clamps.
• Lift the core from the case. Do not use force. Take care not to damage the fins of the heater core when removing.
• To reinstall the heater core, reverse the removal steps.

When the heater core leaks and must be repaired or replaced, it is a very difficult and time-consuming job primarily because of the core's location deep within the firewall of the car. For this reason always leak test a replacement heater core before installation.

These instructions come from Chilton.
1. Disconnect the battery negative first.
2. Unbolt the A/C compressor and move it out of the way but DO NOT disconnect the lines from the compressor.
3. Remove the coolant resevoir, if you have one.
4. Disconnect the wiring from the motor, and the cooling tube if there is one.
5. Remove the mounting screws from the motor and pull it out. If it sticks because it is attached with a sealer, then pry GENTLY against the case to remove the motor.
6. Installation is the reverse.
These instructions are only good for 80-82 models. Hope this helps.

First check each wheel brake cylinder for small leaks. If no leaks then the brakes have not been bled properly. Liquid will not compress like air, thus the reason pumping the pedal makes the brake pedal come up. If you had all of the air out of the lines then you pedal would not be soft. With your pedal going to the floor either there is air in the lines or fluid is slowly leaking.If it is a small leak on one of your wheel cylinders, it may be hard to detect without pulling the wheels off and looking. Small leaks on your wheel cylinders may never drip off of the car.

yes, there is a relay, but it's part of the anti-theft system. See diagram below.

small blisters in paint are normally caused by moisture in the air when painting.if the original was not cut back and then filler/primer was not applied in a heated spraybooth,you will suffer again and again..

http://forums.corvetteforum.com/c3-tech-performance/1950185-81-fuse-box-diagram.html

if your a/c system is low on freon it will kick on and off frequently,have it checked for leaks cars don't just run out of freon.if that is fine make sure you are getting enough air in through the front of the car.if the condenser in front of the radiator is not being cooled by incoming air the high side of your a/c system will get to high and the compressor will kick off more frequently to let pressure off the system.

the idle adjustment needs to be performed warm but the mixture screws at or near the base have springs on then they need turned in all the way and backed out 2 turns then when the vehicle is warm the idle screw is near the linkage also with a spring on it if you have a tach in the car it should its a corvette lol turn the screw in or out until the car idles around 750 to 850 rpm it idles up automatically when cold if your choke is set properlythis should get you where you need to be you may need to adjust mixture screws a little the only proper way to do this is with a vacuum box but you will be in the ballpark anyway with the method i gave you

The light comes on to to let you know there is low pressure in the system. If the fluid was extremely low when you filled it the brake linings are extremely worn or you have leak in the system. I would check under the car for any signs of moisture around the brake lines. If your brake linings are good and no leaks can be found you will need to replace the master cylinder. Good luck

you may need to check all your fuses just in case.also check to be sure the horns plugged in.if all this is good replace the horn itself under the hood.. hope this helps!!

suggest you try the local library we have no diagrams of this system. U may also buy the CD of this manual at the web site below.

http://www.faxonautoliterature.com/1981-Chevy-Service-Manuals-CD-ROM-Shop-Overhaul-and-Body-Manuals-P20339.aspx

the transmission needs to be rebuild

You pour the transmission fluid thru the dipstick tube.

My 81 did that, cable has needs replaced under the hood. To open lift up hood on drivers side, slide hand under hood and pull cable where it hooks to latch.

There is recorded case of oil soaking thought bottom of the distributor.
Open the cap and look the any sign of oil from the o-ring seal.
== Do not rule out vacuum advance line/hose. ==
Do a short test ran without air filter to rule out air restriction.
Add injector clean to rule out bad fuel. I recommend Lucas fuel additive.

Remove the switch and jump the B+ wire with any of the other two wires and see if the motor responds . If it does you have a bad switch. If it doesn't you have a defective motor.

Simple remove heat shields, removed four bolts on each set(therefore there are 8bolts total) remove exhaust manifold clean manifold replace with new gaskets. If bolts are rusted spray them with any lubricant the night before the job use a new socket and have a sandwhich and a cold beverage handy. Enjoy this its easy and fun. Don't sweat it if you break a bolt in the manifold... just let me know and I'll walk you threw it. .. By the way its a good time to use some dressing on the manifold pipes. It will make the engine seen new.

Biggest problem is neutral safety switch. When it goes you have no crank no start. A pain to get too have to remove driver seat and be a gynmist to get to it. Most customers turn its circuit into an ignition kill switch and do not replace it.
Next suspension and tires are fickle. At oil change intervals check all ball joint for wear and keep monitoring steering damper for dents and leaks.When this puppy goes you'll have steering wheel oscillations. very easy to replace and not that costly.
Tires just all around **** with this car. If you get 25k out of a pair( regardless of what brand) you did good.
If you have a manual transmission shifter rattles in third gear.
valve cover gaskets every 3-4 years
Calipers leak, there is a TSB on this basically hunt down a good brand and use them.
R4 A/C compressor is very fickle usually dies within 4 years of service.
A/C control head is in a bad spot and is effected by road conditions. pays to have extra parts for this hanging around ( vacuum valve,and setting switch and clear plastic cover)
Also good to keep power window switches handy.
Power seat motor usually good in all positions except tilt position.
Power seat connectors prone to fail due to corroded terminals.
Water pump goes every 50k .
lastly leaf springs , replace silencers every 25k or when squeaking is unbearable.

It is most likely the brake hoses going to the brake calipers,they stop up on the inside,If this was at all helpful,please rate,thank you.

Check ball joints , steering linkages and tires. Doesn't take much for a defective radial tire to make this puppy pull.