Bronco L6-300 4.9L VIN Y 1-bbl (1983)
Exhaust Manifold: Service and Repair
Fig. 16 Intake & exhaust manifold tightening sequence. Exc. 1987 6-300
6-300
1.
Remove air cleaner.
2.
Disconnect accelerator cable or rod from carburetor or throttle body and remove accelerator retracting spring.
3.
On models equipped with automatic transmission, remove kickdown rod retracting spring and accelerator rod bell crank assembly.
4.
On all models, disconnect and tag fuel inlet line and all vacuum lines at carburetor or throttle body.
5.
Disconnect carburetor feedback solenoid connector or EEC connector from throttle body and the choke cap electric assist connector, if equipped.
6.
Disconnect exhaust pipe from exhaust manifold.
7.
Disconnect power brake vacuum line, if equipped.
8.
Remove manifold attaching bolts and nuts and the intake and exhaust manifolds as an assembly.
9.
Remove attaching nuts and separate intake and exhaust manifolds.
10.
Reverse procedure to install. Torque manifold attaching bolts and nuts to specifications in sequence shown in Figs. 16 and 17. The following
manifold installation procedure should be used to extend exhaust manifold service life:
a. Clean cylinder head and manifold mating surfaces.
b. Remove tube fittings from original manifold and install in replacement manifold, as needed.
c. Apply suitable graphite grease to exhaust manifold-to-intake manifold mating surfaces.
d. Install 2 new bolts (part No. 374047-S) and a new stud (part No. 381733-S) into intake manifold.
e. Assemble intake manifold to exhaust manifold using lock washers and nuts. Tighten nuts finger tight only at this time.
f.
Install a new intake manifold gasket. Do not install a combination intake/exhaust manifold gasket on a new exhaust manifold.
g. Apply suitable graphite grease to cylinder head-to-manifold mating surfaces.
h. Position manifold assemblies against cylinder head, ensuring intake manifold gaskets have not moved.
i.
Install manifold attaching bolts and nuts and torque to specifications in sequence shown in Figs. 16 and 17.
j.
Torque intake manifold-to-exhaust manifold attaching nuts to 22-32 ft. lbs.
k. Position a new gasket on exhaust pipe, then connect pipe to manifold and torque attaching bolts to 25-38 ft. lbs.
