What causes the rear end to sag on a 1987 Toyota 4Runner?
the rear springs have lost their ability to hold the weight. you
can replace them with after market ones or a spring shop . or you
could ad a 2inch block under the spring and still keep the factory
shocks you can pick these up at your local parts store for about
The springs on the 1st gen 4runners are identical to the ones on
the pickup truck, so when Toyota put the fiberglass shell over the
back the springs couldn't support it as well. Read the wikipedia
entry on 1st gen 4runners it will tell you all about it.