How-to
1986 Ford Bronco Timing Chain Replacement
The timing chain on a 1986 Ford Bronco was replaced after the old chain was found with a lot of slack and the aluminum and plastic cam gear was missing part of one tooth. The front cover, balancer sleeve and seal, oil pressure sender and water pump were serviced at the same time, and the engine was run and timed at the end.
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Step 1
Begin the timing chain replacement at the front of the engine. Loosen the water pump bolts, then remove them one at a time and poke each one through cardboard in the position it came from.
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Step 2
Remove the bottom four oil pan bolts. slim68 also removed the oil pressure sender unit and its extension, then cleaned the area up for a new sender.
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Step 3
Take the front cover off and inspect the timing set. slim68 found a lot of slack in the chain and a little bit missing on one tooth of the aluminum and plastic cam gear.
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Step 4
Clean the exposed front of the block and the sealing surfaces.
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Step 5
Chase all the threads. Spray carb cleaner to get rid of the debris left from gasket removal, then blow the bolt holes out with a final shot of air.
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Step 6
Fit the new Cloyes double roller timing set. slim68 left the fuel pump eccentric off because the truck runs electric fuel pumps.
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Step 7
Soak the front cover in solvent to help get it clean. While the cover soaks, start work on the balancer; slim68 reports the end cleaned up but was grooved from the old seal.
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Step 8
Put Loctite on the repair sleeve and install it over the grooved area. slim68 used a nice flat piece of UHMW and a dead blow to drive the sleeve on easily.
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Step 9
Finish cleaning the front cover. Knock the locating pins out a little, since they were sitting flush with the cover, then install the new seal.
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Step 10
Put the front cover back on and install the new sending unit.
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Step 11
Install the balancer, working the outer lip of the seal so it does not roll, then install the water pump and torque it down. slim68 painted the timing indicator and the 12* mark on the balancer to make the timing easier to set.
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Step 12
Install the power steering pump and air conditioning compressor, finish the rest of the reassembly, drain the oil because coolant and other material went down into the sump, add a 50/50 coolant mix, then start the engine, let it warm up and set the timing. slim68 traced a loud whistle to a big vacuum leak where the EGR bolts up, which was keeping the throttle plate from seating against the intake, and fixed it by loosening the EGR, tightening the throttle plate and then the EGR; the photos end there.
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