In 1990, development of a successor to the YJ began in Chrysler's "Jeep-Truck Engineering Pre-Program" department under Bob Sheaves and TJ program director, Craig Winn. Mules based on the YJ were built from 1990 to 1993, when formal approval was given for the TJ development program at a 0 million budget. From 1991 to 1992 designers worked at the new Chrysler Technical Center, building on various design proposals. In late 1992, Michael Santoro's TJ proposal was chosen by Tom Gale, Lee Iacocca, and executive management. In May 1993, now with engineering and supplier input, Santoro's final Wrangler production design was frozen at 32 months ahead of initial assembly. Verification prototypes using production bodies were built from early 1994 and tested through late 1995. As YJ production ceased in December 1995, the last pre-production TJ examples were assembled, with start of series of production in January 1996. Unveiled on January 2, 1996, at the 1996 Detroit Auto Show as an early 1997 model year introduction (1996 model year skipped), the TJ was an evolutionary update. It later arrived in Jeep showrooms in April 1996, after 6 years of overall investment and 36 month production development phase.Instead of leaf springs, this updated Wrangler featured a modern coil-spring suspension, front and rear, based on that of the Jeep Grand Cherokee, for better ride and handling, and a return to the classic CJ's round headlamps. The engine is the same 4.0 L AMC 242 Straight-6 used in the Cherokee and Grand Cherokee. A 2.5 L AMC 150 Inline-4 engine was available on entry-level models until 2002. The 2.4 L DOHC 4-cylinder engine previously used on the Chrysler PT Cruiser replaced it for 2003.A right hand drive version of the TJ was available for export markets, and was also offered for sale to U.S. rural route postal carriers. The version offered to U.S. postal carriers was only available with an automatic transmission.

In 1998 (MY1999), the fuel tank became standard at 19 U.S. gallons (72 L; 16 imp gal) capacity. There were some changes between the 2002 and 2003 years. From 1996 to 2002, the side door mirrors were black metal framed mirrors; and from 2003 to 2006 they were plastic molded mirrors. The fit of hard and soft tops is slightly different, and the fabric and colors available changed from 2001 to 2003. In 2002 (MY2003), the 3-speed automatic transmission was replaced with a 4-speed automatic with overdrive. The overdrive can be turned off with a dash switch. The radio bezels went from a rectangle in 2002 to a rounded-edged rectangle for 2003. The sound bar inside was changed to sound pods. The interior seats also changed design, going from a rounder model to one with a distinct separation between back and headrest areas. The standard skid plate was also revised for 2003 to make room for the Rubicon's bigger NV241OR transfer case. The change from the 30/32RH to the 42RLE also gained an additional skid plate. This version of the Wrangler is also notable for being the last production vehicle to use AMC-related parts. The AMC Straight-4 engine was retired after the 2002 model year, and both the AMC Straight-6 engine and the door handles (the latter of which first appeared on AMC vehicles in the 1968 model year) were retired along with this generation in 2006. Like the YJ Wrangler, the TJ Wrangler used both the AMC passenger car door handles as well as the larger door handles off the AMC-built Jeep CJ for higher-end models.

 

### Tools Needed:
1. **Jack and Jack Stands** - To lift and secure the vehicle.
2. **Socket Set** - 10mm, 13mm, 15mm, and 18mm sockets.
3. **Ratchet and Extensions** - For better reach.
4. **Wrench Set** - Similar sizes to socket set.
5. **Pry Bar** - To leverage and remove components.
6. **Torque Wrench** - To ensure proper tightening.
7. **Hammer** - For tapping stubborn bolts or bushings.
8. **Ball Joint Separator** (if needed) - For separating joints without damaging them.
9. **Grease** - For new bushings.
10. **Replacement Trailing Arms** - Ensure they are the correct parts for your Jeep Wrangler TJ.

### Safety Precautions:
1. **Work on a Flat Surface** - Ensure the vehicle is on a stable and level ground.
2. **Use Jack Stands** - Never rely solely on a jack; always use jack stands for support.
3. **Wear Safety Gear** - Safety glasses and gloves are recommended.
4. **Disconnect Battery** - To avoid any electrical issues while working under the vehicle.

### Step-by-Step Replacement:

#### 1. **Preparation:**
- Park the Jeep on a flat surface and engage the parking brake.
- Disconnect the negative battery terminal to prevent electrical issues.

#### 2. **Lift the Vehicle:**
- Use the jack to lift the rear of the vehicle.
- Place jack stands under the rear frame to secure it.

#### 3. **Remove the Wheels:**
- Use the socket and ratchet to remove the lug nuts.
- Take off the rear wheels to access the trailing arms.

#### 4. **Locate the Trailing Arms:**
- The trailing arms are located behind the rear axle, connecting the axle to the frame.

#### 5. **Remove the Old Trailing Arms:**
- **Upper Bolts:** Start by removing the bolts at both ends of the trailing arm using the appropriate socket and wrench.
- **Lower Bolts:** Repeat for the lower bolts. If bolts are stuck, use the hammer to tap them gently, or a pry bar for leverage.
- **Ball Joint Separator:** If necessary, use this tool to separate any ball joints without damaging them.

#### 6. **Inspect Components:**
- Check the bushings and mounting points. If they are worn or damaged, you may need replacement bushings or mounting hardware.

#### 7. **Install New Trailing Arms:**
- Align the new trailing arms in place.
- Insert new bolts (if required) through the mounting points.
- Hand-tighten the bolts first, then use a torque wrench to tighten them to the manufacturer’s specifications (usually found in the service manual).

#### 8. **Reinstall the Wheels:**
- Put the rear wheels back on and hand-tighten the lug nuts.
- Lower the vehicle off the jack stands using the jack.

#### 9. **Torque the Lug Nuts:**
- Once the vehicle is on the ground, use the torque wrench to tighten the lug nuts to the specified torque setting.

#### 10. **Reconnect the Battery:**
- Reconnect the negative battery terminal.

#### 11. **Test Drive:**
- Take the vehicle for a short test drive to ensure everything is functioning correctly.

### Common Pitfalls to Avoid:
- **Over-tightening Bolts:** This can strip threads or damage components.
- **Not Using Jack Stands:** Relying only on the jack can lead to serious injury.
- **Forgetting to Inspect Other Components:** Always check adjacent parts for wear while you have access.
- **Ignoring Torque Specifications:** Always follow the manufacturer’s guidelines for torque settings to avoid failures.

### Replacement Parts:
- Ensure that you have the correct trailing arms for your specific model.
- Consider replacing bushings if they show signs of wear.
- Inspect bolts and hardware; replace if corroded or damaged.

By following these steps and precautions, you can successfully replace the trailing arms on a Jeep Wrangler TJ.
rteeqp73

Summary first (quick map)
- Purpose: restore a leaking/failing air-suspension system so the Jeep holds height and rides safely.
- Big parts: airbags, compressor, tank, valve block (solenoids), airlines & fittings, dryer/moisture trap, pressure switch/relay/fuse, height sensors/controller, mounting brackets & hardware, shocks.
- Approach: diagnose leaks/electrical, relieve pressure and support vehicle, replace faulty component(s), route/install parts properly, leak-test, adjust and road-test.

Why this repair is needed (theory, simple)
- Air springs act like balloons supporting the vehicle. Compressed air is the “spring” — change the pressure and the stiffness/height changes. The compressor pumps air into a tank and valve block to fill the airbags. The valve block (with solenoids) routes air to each bag on demand; the pressure switch/ECU tells the compressor when to run.
- Over time things fail: rubber airbags crack/rupture, airlines chafe or pinch, fittings leak, compressors burn out from excessive cycling, dryers clog, valves stick or solenoids fail, or electrical faults prevent operation. A leak is like a slow puncture in a bicycle tire — the system slowly loses air and the Jeep sags.
- Damping (shock absorbers) is separate — air controls ride height and spring rate, shocks control motion. If only air fails the vehicle will sit low but may still bounce dangerously.

Analogy: Think of the system as a house air supply:
- Compressor = air compressor in the basement (makes air),
- Tank = storage tank (keeps reserve so compressor doesn’t run constantly),
- Valve block = plumbing manifold that sends air to each room,
- Airbags = inflatable furniture supporting the house’s weight,
- Dryer = water trap so moisture doesn’t ruin the furniture,
- Height sensors = thermostats telling the system when a room is too low/high.

Main components — what each is and what to watch for
- Airbag (air spring): rubber/nylon bellows. Fails by cracking, splitting, separation at bead, or mounting failure. Inspect for dry rot, tears, bulges at bead, rubbing marks.
- Compressor (electric): pumps air. Fails from overheating, worn brushes, burned windings, or being undersized for the leaks/usage. Symptoms: won’t build pressure, runs continuously, clicks off on thermal cutout, high amp draw.
- Reservoir tank: stores pressure. Fails if rust holes develop or fittings leak. Drain any water by removing drain if present.
- Valve block / manifold: contains solenoids that route air to each bag. Fail by sticking, electrical fault, or internal leak between ports.
- Dryer/moisture trap: removes moisture. If saturated, moisture reaches components, freezes, causes corrosion or valve sticking.
- Pressure switch / transducer / ECU: senses pressure and controls compressor. Faults cause compressor to never run or run nonstop. Electronic controllers/panels also can fail.
- Airlines & fittings: nylon or rubber tubing and push-fit or threaded fittings. Fail by abrasion, pinching, loose push-fits, or cracked fittings.
- Height sensors (if equipped): potentiometer or switch that tells controller vehicle height. Misadjusted or broken sensors cause incorrect inflation/deflation.
- Shock absorbers & mounts: must be compatible. If shocks are worn, ride control suffers even with correct air pressure.
- Mounting brackets & hardware: bolts can loosen or shear; bracket corrosion can displace airbags.

Tools & supplies you’ll need
- Safety: eye protection, gloves, jack stands, wheel chocks.
- Basic tools: floor jack, jack stands, sockets/ratchet set, wrenches, pliers, torque wrench.
- Air tools: airline cutting tool, thread sealant for NPT (PTFE tape or pipe sealant for tapered threads), but DO NOT use tape on push-to-connect or barbed fittings.
- Leak detection: spray bottle with soapy water or electronic leak detector.
- Multimeter, test light, clamp ammeter (optional) for electrical diagnostics.
- Replacement parts: new airbag(s), compressor, fittings, airlines, manifold or solenoid as needed, dryer cartridge, wiring/fuse/relay if needed.
- Manufacturer’s service manual or kit instructions for specific torque values and bracket orientation.

Safety first (must-read)
- Always relieve system pressure before disconnecting airlines or airbags. A charged airbag can move suddenly and injure.
- Support the axle/body with jack stands rated for your Jeep — never rely on the jack.
- Disconnect negative battery terminal when working on electrical components.
- Use appropriate PPE; be cautious of compressed air and pressurized tanks.
- If you’re uncertain about structural mounts or high-pressure components, get a professional.

Diagnosis — find the culprit (step-by-step)
1. Visual inspection: with vehicle parked and safe, inspect airbags, airlines, fittings, compressor, tank, valve block, wiring for obvious damage or disconnected parts.
2. Pressure observation: if the Jeep sits low, note if it holds height for some time or immediately sags. Immediate sag often indicates major leak; slow sag indicates smaller leak.
3. Listen: Start system and listen for compressor running. If it runs continuously, likely leak or faulty pressure switch.
4. Soapy water test: pressurize system to normal operating pressure (use the controller or run compressor until it stops), then spray all fittings, bag folds, bead areas and airlines. Bubbles indicate leak(s).
5. Isolate leaks: shut solenoids or use valve block to isolate corners; test one bag at a time. You can pressurize a single bag via valve block and check.
6. Electrical checks: with multimeter check for proper battery voltage at compressor feed, check fuses/relays, check pressure switch continuity. Measure compressor current draw; excessive amps indicate binding.
7. Valve block: if solenoids make clicking sounds but air doesn’t route, suspect blocked lines or internal valve leakage. Use manifold diagnostics per kit.
8. Height sensor/test panel: simulate sensor movement while observing controller; if controller behaves erratically, sensor or controller may be bad.

Common problems and their typical fixes (quick reference)
- Torn/cracked airbag = replace bag (inspect mounts).
- Airline leak at push-fit = cut back to clean end and reinsert or replace fitting/hose.
- Threaded fitting leak = remove, re-apply correct thread sealant, torque appropriately.
- Compressor runs nonstop but tank stays low = leak in system or pressure switch failure. Pressure-test/soapy water.
- Compressor runs and tank builds then compressor cycles very frequently = small leak or bad tank check valve.
- Moisture in tank or valve block = replace dryer cartridge and check drain.
- Valve block internal leak = replace manifold or rebuild solenoids.
- Electrical: blown fuse/relay = replace and trace short; bad ground = clean and reattach.
- Height sensor bad = replace or re-calibrate per controller’s procedure.

Step-by-step repair examples
Note: below are generic steps; follow the specific kit or component instructions and torque specs when available.

A) Replace a leaking airbag
1. Safety: park level, chock wheels, remove negative battery cable if working near electrical. Raise axle with jack and support on jack stands. Relieve air system pressure (deflate bags).
2. Support axle: put jack under axle to support load if you’ll unbolt lower mount.
3. Remove wheel for access.
4. Remove lower mounting hardware for the bag (may require removing shock or sway bar bracket depending on kit). Keep track of bolt sizes.
5. Pull the bag out of upper mounting plate then disconnect airline fitting from the bag (deflated). If a clamp is used, remove it.
6. Inspect bracket and install replacement bag into upper mount. Reattach lower mount hardware. Use new hardware if original damaged.
7. Reconnect airline, ensure proper insertion and that the fitting is clean. For push-to-connect, push straight in until fully seated. For threaded, use proper thread sealant on tapered threads only.
8. Lower axle to let bag take load. Torque bolts to spec (use manufacturer values). Reinflate slowly and test for leaks.
9. Road-test and re-check fittings.

B) Replace compressor
1. Relieve system pressure. Disconnect negative battery cable.
2. Locate compressor (usually under body or in engine bay). Disconnect electrical connector and mounting bolts. Also disconnect airline to tank.
3. Remove compressor with bracket. Note any foam/damps to reduce vibration; reuse or replace as needed.
4. Install new compressor: mount, connect airline to tank (use proper fittings), reconnect electrical harness. Use correct gauge power wire, fused near battery; install relay per manufacturer diagram.
5. Reconnect battery, run system and check for correct operation and amperage draw. If compressor draws excessive amps, switch or interference may indicate wiring fault.

C) Replace valve block / manifold
1. Relieve pressure and disconnect battery.
2. Remove electrical connector(s) and airlines (label them to keep track).
3. Unbolt manifold and inspect for corrosion or water.
4. Install new manifold in correct orientation, connect airlines to their matching ports, plug in wiring.
5. Re-pressurize and test each solenoid/bag operation. Use soapy water to confirm no leaks.

Routing and installation best practices
- Keep airlines away from heat sources (exhaust, catalytic converter) and moving parts (suspension travel, steering).
- Use protective sleeves and secure lines with zip ties placed where they won’t chafe.
- Keep airlines with smooth bends — don’t kink.
- Use right fittings. Don’t use PTFE on push-fit fittings.
- When reinstalling tanks or compressors, ensure drain or moisture traps are accessible for service.

Testing & final checks
- After repair, pressurize to operating pressure and leave for 30–60 minutes; re-check for leaks.
- Cycle the system through inflate/deflate to confirm valves work and height sensors are correct.
- Check compressor duty cycle: a healthy system should have compressor cycle on for a short time to top-off; constant running indicates leak or insufficient system capacity.
- Road-test for handling and re-check for leaks and noises.
- Re-torque any hardware after a short test drive.

Maintenance tips to avoid future problems
- Install an inline dryer and replace the cartridge periodically (especially in wet climates).
- Drain tank and inspect for rust; if tank is rusty inside, consider replacement or install an external dryer.
- Regularly inspect airlines and fittings for rub spots.
- Keep compressor area clean and mounting hardware tight.
- Check electrical connections and fuse ratings.

When to call a pro
- If pressure tanks are corroded or you suspect internal tank damage.
- If electrical diagnosis shows intermittent shorts or high current draws you cannot isolate.
- If the entire manifold/controller is complex or integrated into vehicle electronics and requires recalibration tools.
- If mounting points are rust-compromised or frame damage is present.

Quick troubleshooting cheat-sheet (symptom → likely cause)
- Car slowly sags over hours: small leak in airline, fitting, or bag.
- Car instantly sagging after parking: big tear in bag or failed fitting.
- Compressor runs nonstop: leak or faulty pressure switch/relay.
- Compressor clicks off and won’t run: blown fuse, bad relay, faulty pressure switch, or no battery power.
- One corner won’t hold pressure: leak in that bag, airline, or manifold port.
- System freezes / valves stuck in cold weather: moisture in lines/tank; dryer failure.

Final notes
- Accurate diagnosis saves money: find leak first, don’t replace everything at once unless damaged.
- Use replacement parts rated for your system’s max pressure.
- Follow manufacturer torque specs and wiring diagrams when available.
- Safety: relieve pressure and use jack stands.

That covers the theory, components, common failures, diagnostics, step-by-step replacement examples, testing, and safety essentials for air-suspension repair on a Jeep Wrangler TJ.
rteeqp73

Acting as an experienced tech — below is a concise, practical, step‑by‑step procedure to remove and replace the radiator on a Jeep Wrangler TJ (1997–2006). Covers tools, safety, how to use the tools, replacement parts commonly needed, and common pitfalls.

Tools and supplies
- Basic hand tools: 3/8" and 1/2" ratchets, metric socket set (8, 10, 13, 15 mm commonly), extensions.
- Wrenches: combination wrenches including 10, 13, 15 mm. A line (flare) wrench set is useful for cooler fittings.
- Screwdrivers: flat and Phillips.
- Pliers: slip-joint, needle-nose, hose-clip pliers (or pliers for worm clamps).
- Fan clutch wrench or long breaker bar and holding tool (to remove mechanical fan clutch if necessary).
- Drain pan (large), funnel, shop rags.
- Jack and jack stands or ramps (if extra clearance needed).
- Coolant catch container and absorbent pads for spills.
- Quick-disconnect tool set (handy for transmission cooler quick-connects).
- Torque wrench (recommended for final torqueing).
- Replacement parts and consumables: new radiator (OEM or equivalent), new radiator cap (recommended), new hose clamps (prefer worm-drive or constant-tension), new upper/lower radiator hoses often recommended, fresh coolant (Mopar‑approved or equivalent; 50/50 pre-mix or concentrate + distilled water), replacement O‑rings for transmission cooler lines (if applicable), new shroud grommets/mounts if brittle.
- Safety gear: gloves, safety glasses.

Safety precautions (do these first)
- Work only on a completely cool engine. Never open the radiator cap or drain a hot system — risk of severe burns.
- Disconnect negative battery terminal to avoid accidental fan activation or shorts.
- Use jack stands if raising the vehicle; do not rely on a jack alone.
- Capture and recycle coolant. Antifreeze is toxic — avoid spills and dispose according to local regulations.

Procedure — step by step
1. Prepare and cool down
- Park on level ground, set parking brake, shift to park (or 1st gear on manual).
- Allow engine to cool fully (several hours after shutdown).

2. Drain coolant
- Place drain pan under radiator petcock (bottom passenger side). Open petcock or loosen lower hose clamp and remove lower radiator hose to drain. If petcock broken, loosen hose at lower connection.
- Remove radiator cap only after engine is cool and drained.

3. Remove upper components for access
- Remove the plastic grille and/or top splash cover if needed (push clips or screws).
- Disconnect overflow tank hose from radiator neck; remove/relocate the overflow tank if it blocks access.
- Disconnect the fan shroud mounting bolts where they attach to the radiator support — do not remove shroud from fan unless needed.

4. Remove fan/shroud and fan (mechanical vs electric)
- Electric fans: unplug electrical connector(s) and remove fan shroud bolts; pull fan/shroud assembly back and out.
- Mechanical fan (viscous clutch): remove the fan and shroud as an assembly if possible. If not, remove fan clutch nut from water pump (use fan clutch wrench or hold pulley with long breaker bar while breaking nut). Remove fan and then shroud.
- How to use tools: the fan clutch nut can be tight — use penetrating oil, a long breaker bar, or specialized two‑wrench fan tool. Hold the water pump pulley steady behind the fan while breaking the nut; be careful not to damage the pulley.

5. Disconnect radiator hoses and lines
- Remove upper radiator hose clamp and hose. Then remove lower hose (if not already removed to drain).
- If vehicle has automatic transmission, disconnect transmission cooler lines at the radiator. These may be quick‑disconnect fittings or threaded fittings:
- For quick‑disconnects: use the correct size disconnect tool insert the tool into the fitting to release the clip and pull the line off. Have a drain pan ready to catch ATF.
- For threaded fittings: use a line wrench to prevent rounding. Replace O‑rings if present.
- Disconnect any sensor or electrical connectors mounted to the radiator area (e.g., fan sensor).

6. Remove radiator mounting hardware
- Remove the upper radiator mounting bolts (usually 2–4 bolts along top mounting brackets) and any lower retainers/mounts. Support the radiator as you remove the last bolts.

7. Remove radiator
- Carefully pull radiator straight rearward. Watch the AC condenser in front — radiator will come out from behind condenser. Do not pry against or bend the condenser. If condenser contacts radiator, slowly maneuver radiator free.
- Inspect for broken mounting grommets, clips, or fins.

8. Transfer parts to new radiator (if needed)
- Transfer fan shroud, mounting grommets, petcock, and radiator cap neck pieces to new radiator as required. Replace any brittle grommets.
- Ensure new radiator has the correct transmission cooler fittings (if automatic) and inlet/outlet positions.

9. Install new radiator
- Set radiator into position aligning lower cushions and mounting points. Reinstall upper mount bolts snugly.
- Reconnect transmission cooler lines using new O‑rings if supplied; ensure proper seat and clips engage. Tighten threaded fittings to snug; don’t over-torque.
- Reinstall lower and upper radiator hoses and secure clamps. Replace clamps if old or corroded.
- Reinstall fan and shroud. If reusing fan clutch, torque fan nut to factory spec (if unknown, tighten snugly and check in repair manual — over‑tightening can damage bearings).
- Reinstall overflow hose to reservoir and reattach reservoir if removed.

10. Refill and bleed cooling system
- Close petcock. Refill radiator with the recommended coolant (Mopar/OEM spec). If using concentrate, mix 50/50 with distilled water.
- Start engine with radiator cap off, set heater to max heat and blower on low to circulate through heater core. Squeeze upper radiator hose to help burp trapped air. Watch coolant level and top up as air bleeds out.
- When thermostat opens (noticeable drop in temp gauge and increased flow in radiator), add more coolant to maintain full level. Run until air stops burping and temperature stabilizes.
- Replace radiator cap, let engine reach normal operating temp, and check for leaks. After cool down, recheck coolant level in radiator and overflow and top off.

11. Final checks
- Inspect all connections and for leaks (radiator hoses, cooler lines, petcock, shroud area).
- Recheck fan operation (with engine running) and shroud clearance.
- Road test gently and recheck for leaks and coolant level after a short drive and after engine cools.

Common replacement parts recommended
- New radiator (ensure correct TJ year/engine/AC/transmission spec).
- Radiator cap.
- Upper and lower radiator hoses (if hoses are older or swollen).
- Hose clamps (recommended).
- Transmission cooler line O‑rings (if applicable).
- Fan shroud grommets/bushings.
- Thermostat (optional but a good practice when replacing radiator).
- Coolant (proper type for Jeep; do not mix incompatible chemistries).

Common pitfalls and how to avoid them
- Working on a hot engine — severe burn risk. Always wait until fully cool.
- Damaging A/C condenser fins — avoid prying between condenser and radiator. Remove radiator straight back.
- Forgetting to disconnect ATF cooler lines properly — use the correct quick‑disconnect tool or line wrench; expect some ATF loss.
- Cross‑threading cooler fittings — start by hand, then snug with wrench.
- Reusing worn hoses/clamps — clamps can leak; replace if corroded or hoses are old.
- Not burping the cooling system — leads to overheating. Use the heater on hot and squeeze hoses to release trapped air.
- Mixing incompatible coolant types — stick to Mopar‑approved or what your vehicle uses; flushing and using correct coolant prevents corrosion.
- Over‑tightening fan clutch or plastic fittings — can break components. Use factory torque specs when available.

Notes specific to TJ (1997–2006)
- Automatic TJ models have transmission cooler lines to the radiator. Manual trans models do not.
- Radiator removal usually does not require discharging A/C; avoid disconnecting A/C lines unless necessary.
- Plastic tanks on older radiators can crack when handled roughly—support the radiator while removing.

That’s the full procedure. Follow the steps in order, use the right tools (line wrench, quick‑disconnect tool, fan wrench), replace consumables (cap, hoses, clamps) as needed, and thoroughly bleed and test the system before finalizing.
rteeqp73