CJ Buyers Guide
Models
CJ7
If you are thinking of getting a Jeep CJ the first thing to ask yourself is what model should you get? The is just a personal preference issue and it really depends on what you are looking for in a Jeep.
The
CJ7 is very common and easy to find parts for.
Flat-Fenders
The flat-fenders are so cool because of their nostalgic simplicity
CJ6 / CJ8
The CJ6 or CJ8 had a longer wheelbase for stability and cargo capabilities.
If you are unsure of what CJ model to get check out our
CJ Spotters Guide.
Engines
Before AMC bought the Jeep corporation in the early '70s there was rarely a choice of
Engines. You usually got a four cylinder engine but from 1966 to 1971 some CJ5's and CJ6's came with the desirable Dauntless “Odd Fire” V6. This was a strong, reliable engine with plenty of low end torque.
Unless high gas mileage is your goal you may want to avoid the 4 cylinder
Engines. The GM “Iron Duke” engine was a particularly weak 4 cylinder engine to avoid. The Iron Duke was found in CJs from 1980 to 1983. It can be identified because the intake is on one side of the engine and the exhaust is on the other. The more desirable AMC 4 cylinder engine has both the intake and the exhaust on the left side.
The AMC era saw some good
Engines 6 cylinder
Engines. The 258 straight six has an excellent reputation as a strong, torquey, reliable motor.
If you are looking for a V8 the AMC 304 was offered from from 1972 to 1981.
Transmissions
The '70s saw some good strong
Transmissions but they were often 3 speeds. The best transmission to ever go into a CJ was the T18 four speed. It was available from 1971 to 1979. Many (but not all)
T18 Transmissions had a granny low first.
In the '80s the three speeds were gone and overdrive was becoming common, but the '80s also saw some of the worst
Transmissions to go into CJs. If you are looking for CJ from the '80s try to get the T176 four speed.
The best automatic transmission to go into a CJ was the TH400. This transmission was available from 1976 to 1979 and it only came with the QuadraTrac transfer case.
Transfer cases
Jeep CJ's have had some excellent
Transfer Cases. The Dana 18, 20 and 300 were all good strong gear driven
Transfer Cases.
The QuadraTrac transfer case was unique for many reasons. It was the only full time four wheel drive system offered in a CJ. It was the first chain driven transfer case. If the oil level was not always kept up the chain would stretch, possibly to the point of jumping teeth.
Frames
When you begin looking for your CJ, one place you really want to check is the frame itself. The newest CJ out there has seen 26 years of wear and tear and you want to make sure it has a solid foundation.
Rust
CJs have a few common rust areas that should be checked before purchase. The first area to check would be around the front and rear shackle mounts. Mud and dirt get in these areas and block the holes in the boxed frame
Models not allowing moisture to escape. Check them thoroughly with a hammer and screwdriver.
The next area to check would be the section located directly behind the rear wheels. Use the same method as described above. Also look at the 6 body mounts that attach the tub to the frame.
If your looking at a wide trac model ( 82-86 ) take note of the shock towers located in the front fenders. These held water between the frame and the tower itself and are another common rust area.
It is best to go over the entire frame if possible. Any area that could hold moisture in is a potential problem rust area and compromises the integrity of the frame.
Cracks
While your under your possible next project checking for rust, look for cracks in the frame as well.
On early "c" channel (non boxed) frames pay attention to the whole frame. These frames have most likely been put through quite a few "flex cycles" and warrant attention throughout the entire frame.
On later boxed frames ('76 and up) one of the most common areas to see cracks is around the steering box area. Take note of this area especially on CJs with lift kits and oversized tires.
Summary
The frame is the basic building block or "backbone" of your CJ. A rusted and or cracked frame has been the demise of many CJs over the years. When at all possible check the full frame thoroughly. The points where the suspension and steering mount are critical to the safety of your CJ and should warrant specific attention.
Body
The body is the first thing you see when looking at a potential CJ purchase. Conditions of the body of CJs will run the gamete. From full restoration beauties to ones with holes large enough to lose small children, your likely to see it all in your quest for a CJ.
You'll also run into dings, dents, overall damage and "modifications". You may see repairs made with chicken wire , bondo , aluminum tape and even that aerosol spray foam. It will be up to you to know your limitations when it comes to body repair.
Front Clip
The front clip is easily removed with common hand tools. The fenders , grill, and hood can all be removed with the turn of a few bolts in stock form. Look for rust on the inner fenders and bottom corner that meets the body tub.
Your candidate could also have a fiberglass front clip. These are either bolted on like their steel counterparts or are 1 piece with the fenders and hood molded together. Common things to be aware of with fiberglass are cracks and damaged gel coat.
When inspecting fiberglass look at all the areas where mounts or fasteners are used. This is a common place for damage. Also look for quality of the production of the fiberglass parts. There should be thicker reinforced areas at any mounting points.
When looking at a 1 piece fiberglass front end you will also have to look at the previous owners fabrication. Be wary of poorly mounted radiators and loose or draped wiring harnesses.
Windshield ,doors ,tailgate
The windshield frame is also a common rust area on CJs. Areas to take a good look at are right at the hinges and the top of the frame where screws have been used and holes have been drilled. If water has layed in the frame itself the bottom of the frame can easily rust out. This is often caused by the design of the defroster itself. Warm moist air is pumped through the frame itself causing condensation to rust the bottom of the frame. If you have the opportunity fold the windshield forward and check this area.
If your looking at a CJ with steel doors pay attention to the bottom area when looking for rust. Another problem on full steel doors is a stress crack develops right below the wing window. Also check for brittle and worn weatherstripping around the outside of the door and in the window areas.
Check the tailgate for rust around the weather stripping and for missing cables and / or hardware.
Body Tub
The body tub is where you'll spend all your driving time and should be paid close attention to. There are many common areas for rust on a CJ tub. The rocker area under the doors and the rear corners of the tub are 2 such areas. Many times these areas are shoddily patched or covered with diamond plate.
The body tub sees a lot of stress where the body mounts support the tub. With a little rust or abuse these body mounts can become damaged or press through the body.
Around the wheel wells and under the roll bar are also spots that deserve your attention. If the CJ your looking at has carpeting try and pull it back away from these areas to get a good look.
The entire floor area needs to be inspected as well. Mud, dirt and road salt (for those that live in areas that use it) wreak havoc on the underside of your CJ. Look for poorly replaced/patched floors as well. Patches that are put over rusted metal only become rusted metal themselves.
The last two areas to check are the cowl under the windshield frame and the tailgate area. These areas use weather stripping and a gasket. When either fails it usually holds water in causing rust. You can pop out the two plastic inserts on the inside of the windshield frame and inspect it somewhat using a flashlight.
Inspecting a CJ
One of the biggest things that should be done when looking at a CJ is to inspect for rust and bondo. Remember one of the biggest pains is bodywork. I go around the Jeep knocking every few inches all over with my knuckles. If the owner gets nervous I will walk off.
Next I'll go under the Jeep and inspect the frame. On the frame I'll use a pair of pliers or another tool I have available to find any rusted areas. Once I know the body and frame are sound I move on to the rest of the Jeep.
Remember the seller wants to show you the highlights of the Jeep and steer you from the possible problem areas. Don't get all enamored with showy items , just move on to areas you are interested in.
Project Jeeps
These are possibly the worst Jeeps you can buy. Usually someone selling a project Jeep has found out he is in over his head and has parts from here to Hells half acre (and yes hes lost some important ones) or has started the conversion and found its going to cost a small fortune to complete.
Most Jeeps bought in this condition end up going to a Junk yard or sold as parts Jeeps at a considerable loss. You have to have a backyard full of Jeep parts and and a lot of experience to completely reassemble a torn down Jeep.
Wiring a Jeep from scratch is not a chore for a person who has never worked with wiring before. Doing a engine or tranny conversion can get into thousands of dollars alone.
Remember when you change one item it will usually effect 10 others. Jeep projects are for the experienced rebuilder with a pile of Jeep parts in reserve.
Built Jeeps
Another thing to avoid is Jeeps built to the max. Most of this type have been beaten severely on the trail. With some the build is not what they wanted and trouble has arrived. Why else would he be selling something he has spent thousands on?
While he may just be needing money many times problems have arose that are too costly to fix. Built to the hilt Jeeps are rarely a nice thing.
Street Queens
This is the area you would like to find your Jeep in. With all the information other have written finding a Jeep that has spent most of its life fairly stock will make a fine vehicle to buy.
Yes you can still do whatever modifications you'd like. Maybe you'd even want to do a full frame off restoration. This way you are going to find that the Jeep is easier to find parts for and not run into conversions that are extremely expensive to fix. Street Queens are the way to go when buying a Jeep.
Electrical
This is something that gets hours and hours of attention and discussion. At very best you have an electrical system that is 30 something years old and most have spent significant time in hostile and corrosive atmospheres. At the very worst one or more of the previous owners considered his stereo system to take priority over things as foolish as tail lights. The obvious conclusion is that the more pristine and original the wire is in the easier it is to keep everything running. As always be cautious of the seller who starts by telling about the killer system and/or the 8 day lighters that replaced the high beams.
Good indications of electrical challenges is the number of splices you see with duct tape insulation, before I get jumped on here there are a couple of these from the factory but these would hopefully be wrapped in convoluted tube. Wire nuts and "scotch locks" are a definite no-no. Look at the fuse block. fuses wrapped in tin foil and spent 22 shells are always a dead give away of possible problems. Soldered splices, when splices are necessary , are my first choice but not every body is talented with a soldering iron so if the lump under the heat shrink is a bit large it may be time to pull the pocket knife and take a closer look.
After market wire harnesses, are not magic or blessed from on high and when you are through you don't have the luxury of a factory diagram telling you what color what is and where it is supposed to start and end. If your buying a machine with a replacement harness you already know for a fact the PO has had his way with every wire in the entire system. Tell me that gives you a warm secure feeling.
Having taken all this into consideration, keep in mind that 80% of your problems will be electrical 10% will be vacuum leaks and the other 10% will be deciding what size tires to run and fun easy stuff like that. Of that 80%, half of those will be bad ground connections. Grounding failure is directly proportional to rust and corrosion. Keep this in mind as you are examining the body, it isn't just about looks.
There are enough threads on trouble shooting 12V DC electrical systems and proper use of a VOM that this is not the place to discuss it. As vehicle electrical systems go you are not going to find an easier system to understand or work on than the CJ. Do be prepared to spend some time with the electrical system and if you don't think you can ever get your head around a wiring diagram or be able to learn the difference between volts and ohms you may want to rethink this whole thing before you become the PO that the next guy blames for all the electrical problems.
Emissions
Way back in the 70s the United states government, going under the name of the environmental protection agency, called all the engineers from all the automobile manufacturers into a big meeting room. The head EPA guy then set down the new rules. "What we want is to be able to throw a large basket of meadow muffins up into the air at speeds not to exceed 55 MPH and when these meadow muffins once again fall to the ground they shall be transformed into, not less than, 10K gold." and you know what? they did it!!
We lost a lot of the horses that we had previously associated with those meadow muffins and things, in general, got a lot more complicated under the hood. We were on the way toward saving the planet for future generations of both humans and polar bears. A truly noble cause, I do believe.
Now lets flash forward 30 something years to those of us that are looking for our first CJ. We are looking at decent looking CJ that runs more or less and the current owner is so proud that he removed all that Damned smog junk and threw it in the dumpster where it belonged.
Now, after a little history and a return to the present the big question is what is "the emissions system" and why is it important to me when I am looking for my first CJ.
the emissions system is the equipment that controls the production of pollutants into the environment. that is pretty broad and not worthy of Wikipedia but it's the best I got.
the first and most obvious is the evil empire dictates that some of us who live in liberal controlled western lands and most major metropolitan areas must maintain some level of participation in this program. some of us are not required to have a probe stuck up out exhaust but even these may be required to at least have the offending equipment installed , even if it does not work. This in mind, it may be a good thing to at least own an air injection pump and mounting bracket even if there has not been a belt on the pulley for a few years. Interesting point: you can still buy a pump, air injection manifold and check valves for the AIR system what you can't pick up at the local parts house is the pulley and the mount, the hoses are also something that will require a bit of creativity. So be forewarned!! know the law and what your responsibility to it is. You may find that the "pretty good deal" will never be allowed on the pavement again. I always thought that "all terrain vehicle" included asphalt.
Why do we hate Emissions systems? I think that it is because the available information on the system is minimal at best. If you have to put one of these systems together from point zero your going to have to do research to put the history detectives to shame.
What to look for: there are several very good and worthwhile parts of the system that are very worth saving. The TAC, thermostatic air cleaner. This air cleaner has a damper system in it that is controlled by a coolant temperature switch and powered by manifold vacuum. It draws warm air from the heated chamber mounted to the exhaust manifold until the coolant is at operating temperature and then it switches to cool air through the main intake and possibly a cool air duct routed to the front of the grill. Now considering that the Jeep engine is possibly one of the most cold nature d machines in existence, I figure this is a good thing to have.
The EGR valve, exhaust gas recirculation valve. Now how could putting exhaust gas into the intake manifold possibly be a good thing? come to find out that mixing a little carbon monoxide with the combustion process not only causes a drop in some flavor of bilge the internal combustion engine is so good at producing but is improves fuel efficiency and will make the engine idle smoother. Who would have guessed that!! the PCV valve. this little jewel allows the oil vapor and cylinder blow by to be sucked into the intake manifold to be efficiently burned rather than released into the air. with out a properly working PCV valve you engine performance will bring the meadow muffins back to mind.
There are several more things you will encounter in this part of the adventure like the electric choke, the charcoal canister and that most infamous of all the catalytic converter. Interesting point for all but those in the far western lands, the 1977 CJ was the last year to come from the factory with NO catalytic converter!! You may want to keep that in mind. Every time I envision a catalytic converter I think of driving across a field of tall dry grass with a cherry red piece of steel hanging under the frame.
Now to close this, the bottom line is, obviously, look for as close to stock as possible, just because you do not yet understand it does not make it a bad thing that must be removed and discarded, the society of automotive engineers did not do anything terrible and stupid although a group of politicians more than likely did. The average automotive engineer is for the most part is a pretty sharp guy or gal and they gave us the best tech available at the time, there is better tech today and we can take advantage of some of it but there is a lot of the old stuff that is still valid and we would do well to learn of it and take advantage of it, after all that's one of the reason we have a CJ.
The Test Drive
Okay you've found a Jeep you are interested in and you would like to take it for a
test drive. Call up the seller on a Saturday morning saying you only have a couple hours free and would like to stop by now to check it out. This way the seller won't have time to charge the battery, run the engine or do any other preparation. You want to see how easy it is to start cold.
When you arrive make sure the engine is cold. If not ask why. An honest seller may tell you it's hard to start and he wanted to warm it up for you. That's good but you need to see for yourself. Come back when you can start it cold.
First check under the jeep for puddles of oil or other fluids. Check the oil levels. Make sure you can't detect any coolant or other contaminants in the oil. The brake fluid should be clear. Check the radiator and make sure there isn't anything but coolant in the radiator. Radiator stop leak can often be seen around the radiator cap. Some of these stop-leak products are of low quality and can clog a heater core or radiator orifices. If someone is trying to sell his jeep he may not be buying the best products.
Now for the
test drive. As soon as you have the jeep started drive off to see how it runs cool. Accelerate firmly checking for hesitation and sputter. Go through all the gears and get up to highway speed. Turn on the heater even if it's summer. Do all the gauges work?
The first time you
test the brakes don't do a panic stop in case it pulls to the side or locks up too easily. Once you are sure the brakes are not dangerous try an emergency stop. Check the rear view mirror first and then hit the brakes as if someone has pulled out in front of you.
Find some gravel to
test the four wheel drive. A gravel parking lot is best. Get out and lock the hubs. Try 4WD low and high. When in 4WD make a very tight turn. If 4WD is working it will try to turn the front tires the same speed as the rear. This will cause the tires to slip as you turn sharp. You should be able to hear and feel the tires slip. If the transfer case is a QuadraTrac it has a differential to prevent binding. In that case you will need to lock the transfer case in “Emergency Drive” with the rotary switch in the glove box.
To
test a locking differential back up into a steep slope in 2WD at an angle, so one back tire starts to climb first. The rear tire that is still low is the one that would start spin if the diff is not locked. If it's a select-able locker the most likely problem would be the cable, solenoid or whatever is supposed to activate the locking differential.
When you stop the jeep check all the electrical components. Turn on all the lights, high beams and low, turn signals (both directions), dash lights. Make sure the radio works.
It's okay to bring along a spouse or significant other to check out a used car but he or she shouldn't act too excited, pointing out all the good points on the jeep. Instead let her pick out the problems. If you are the one pointing out every nitpick on the jeep and still make an offer on it, the seller knows you are just trying to lower the price. On the other hand if the spouse is pointing out everything wrong with the jeep and you make an offer, then it looks like it's an uphill battle convincing the wife to buy a 30 year old jeep.
Everyone wants to talk down to get a good deal but don't go too far. If the seller has an extremely low price because he doesn't know what it's worth don't talk him down any more. There’s a difference between getting a good price and ripping someone off.
