NOTE: A special tool is required to compress the valve spring.
- Remove the valve cover and associated parts as required.
- Rotate the camshaft so that the base circle of the cam is against the cam
follower you intend to remove.
NOTE: If removing more than one cam follower, label them
so they can be returned to their original position.
- Using special tool 49-UN01-135 or equivalent, depress the valve spring,
as necessary, and slide the cam follower over the Hydraulic Lash Adjuster
(HLA) and out from under the camshaft.
- Remove each HLA.
- Install the HLA and cam follower in the reverse order of removal. Lubricate
the followers with SAE 50W engine oil meeting current API specification prior
to installing.
- Disconnect the negative battery cable.
- Remove the valve cover.
- Remove the rocker arm/shaft assembly.
- If necessary, disassemble the rocker arm/shaft assembly, noting the position
of each component to ease reassembly.
- Check the surface of the Hydraulic Lash Adjuster (HLA) for wear and damage.
If the HLA is worn or damaged, it must be replaced.
Fig. 1: Remove the HLA from the rocker arm
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- Remove the HLA from the rocker arm. Don't remove the HLA unless necessary,
because oil leakage will occur if the O-ring is damaged.
To install:
Fig. 2: HLA and oil reservoir
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- Follow these steps to install the HLA:
- Pour clean engine oil into the oil reservoir in the rocker arm.
- Coat the HLA with clean engine oil.
- Place the rocker arm and HLA into a tub filled with clean oil, and then
insert the HLA into the rocker arm, taking care not to distort the O-ring.
- Install the rocker arm/shaft assembly.
- Install the valve cover.
- Connect the negative battery cable, start the engine and check for leaks
and proper operation.
- Remove the upper and lower intake manifolds.
- Remove the valve covers.
- Remove the rocker arm/shaft assembly.
- Remove and mark the pushrods for installation.
- Remove the tappets with a magnet. If they are to be re-used, identify them.
NOTE: If the tappets are stuck in their bores, you'll need
a claw-type removal tool.
- Coat the new tappets with clean engine oil and insert them in their bores.
- Coat the pushrods with heavy engine oil and insert them into the bores from
which they came.
- Install the rocker arm/shaft assembly.
- Install the valve covers.
- Install the upper and lower manifold.