Step 2: Replace All Aged Rubber

Rubber degrades. After thirty to forty years, the rubber components on a CJ are not performing
the way they were designed to. Many of them look fine visually but have lost their elasticity, their
sealing ability, or their structural integrity. This matters more than most new owners realize
because rubber connects, isolates, and seals almost every major system on the Jeep.
This step is not glamorous. Nobody gets excited about new body mount bushings.

 But deteriorated rubber is one of the most common root causes of problems that get misdiagnosed
as something more expensive. Worn engine mounts cause vibration that looks like a drivetrain
problem. Worn body mounts allow the tub to flex on the frame in ways that cause squeaks,
rattles, and cracking. Worn leaf spring bushings allow the axle to shift, which creates steering
behavior that looks like a worn steering component.
 

Replace all of it before you start diagnosing other things.

Engine and transmission mounts
 

Collapsed engine mounts allow the engine to move under load and vibration in ways that affect
everything attached to it — exhaust routing, engine hose connections, throttle linkage, and the
feel of the drivetrain. Inspect them visually for cracking and collapse, and feel for excessive
engine movement by prying carefully against the mount with a large screwdriver while an
assistant blips the throttle.
 

Body mounts
 

CJs use rubber body mounts to isolate the tub from the frame. These are commonly neglected
and commonly destroyed by previous rust removal or body work. Missing or collapsed body
mounts allow the tub and frame to contact each other directly, which causes cracking in the tub,
water intrusion, and a general feeling of structural looseness that is hard to trace.
 

Leaf spring bushings and shackle bushings

The leaf springs locate the front and rear axles. If the bushings in the spring eyes or shackles
are worn out, the axle can shift position during suspension travel and under braking or
acceleration. That axle movement affects toe, affects caster, affects steering geometry, and
creates a feeling of vagueness or wander that is very easy to mistake for a steering problem.
Check by having a helper watch the spring eyes and shackle bushings while you move the
suspension by hand. Any movement of the bushing inside the housing means the bushing is
worn and needs replacement.
 

Sway bar bushings and end links

Worn sway bar bushings and links allow more body roll than the suspension was designed for
and introduce clunking and imprecision in the handling. They are inexpensive and easy to
replace.
 

Radiator and heater hoses

Squeeze every hose. It should feel firm and consistent throughout. Soft spots, swelling, or
cracking means the hose needs replacement. A hose that looks fine but feels spongy when
squeezed is a hose that is delaminating internally — it can collapse under suction and restrict
coolant flow without any visible external sign. This is a known cooling problem on CJs that gets
blamed on the radiator when the real culprit is a forty-year-old lower radiator hose with no anti-
collapse spring.
 

Vacuum lines and emissions hoses

The 1982-1986 CJs with the feedback-controlled Carter BBD carburetor have an extensive
vacuum and emissions plumbing system that degrades badly with age. Cracked or
disconnected vacuum lines cause erratic idle, poor fuel economy, and hard starting that is
almost always misdiagnosed as a carburetor problem. Before you throw parts at the fuel
system, spend an hour inspecting every vacuum line. Replace anything that is cracked, hard, or
disconnected.

Brake hoses

Rubber brake hoses are flex points in the brake hydraulic system. They crack externally, but the
more dangerous failure mode is internal deterioration — the inner lining of the hose breaks
down and creates small flaps that act as one-way valves, trapping hydraulic pressure and
causing brakes to drag or not release fully. If the hoses are original or unknown age, replace
them. This is a safety item.