How do you replace the fuel pump located on a 1989 Ford Bronco II?

Answer 1

MOST Bronco 2's from most years originally 2 fuel pumps, one mounted on the frame rail directly below the driver's seat, and the second on mounted inside the gas tank. This is for those.

For either one you need to first make sure the fuel system is depressurized-unless you don't mind getting sprayed with gasoline. If you've started the engine in the last few months just do it. If you've been cranking the engine repeatedly because you think the fuel pump is no good, you've probably already depressurized it.....

Easiest way to relieve system pressure is to trip the emergency fuel cut off switch (passenger side near the hump under the top edge of the carpeting) and crank the engine for about 20 seconds. To trip that switch just whack it-not too hard though. If you hear a click and the button is sticking out with some spring pressure behind it it's tripped. If you find it that way already......push it in and after cranking your engine may start.

The front pump is very easy to replace, if you happen to have a 2WD version. It's tougher with 4WD, because there is such tight access to the front fuel pump that you may have to take the front driveshaft ujoint apart to be able to get the pump out. (If you don't, count yourself lucky and skip past the ujoint instructions.)

I have the official 2" thick FORD TRUCK workshop manual for Bronco2 and it does not explain how to remove the front pumpif it's bracket doesn't clear the frame rail, so here's what's involved.

Ujoint removal/installation.

To the uninitiated this may seem daunting, but know that it's not that difficult. But read this in detail more than once before starting. There are a few little things to watch out for and it's easy to damage a ujoint by rough or careless handling. And there's no fixing a bad one. If you are hoping to reuse the ujoint, go slowly and use as little force as possible to get the job done. If you're replacing one, you don't have to be as gentle on DISSASSEMBLY.

The flat, circular spring clips are there to hold the grease cups of the ujoint's "Spider/cross" in position side to side and to make certain that grease doesn't come out and crud doesn't sneak in.

The clips can usually be pried/tapped out reasonably easily with a screwdriver tapped by a small hammer-sometimes just by pushing/prying with a large screwdriver if they're clean enough and not rusty. REMEMBER that these are STRONG SPRING CLIPS and once out of their groove they WILL fly if you don't stop them. If you lose one it's not that easy to find an exact replacement without buying a whole ujoint, so wrap a rag around the area where you're tapping/prying.

Spray the cup/clip recesses with something that can loosen or dissolve rust and go get lunch or come back tomorrow if they are very rusty looking. On some clips that appear to go all the way around the groove, one end of the flat clip is designed to be able to move inwards past the other end, but the other end can't, so look for a gap between the ends of the clip. Some aftermarket-type clips will have little holes in their ends and need retaining ring pliers to get them out the easiest without damage, but factory ones from that era usually don't. Remove the clips. Put them in a safe place. Clean out the area in front of the cups on both sides if rusty or crud filled.

MARK THE UJOINT'S POSITION AND CROSS SO YOU CAN REASSEMBLE THE CROSS BACK INTO IT THE SAME WAY. Original equipment drive shafts and ujoints are frequently a matched balanced set and if you rotate the ujoint from it's original position there may be a noticeable vibration afterwards-or worse.

There are small diameter, long needle bearings living in grease inside the cups. The bearings are a snug fit onto the machined surface of the spider/cross. The 2 cups are there to hold the bearings and the grease is retained by a resilient seal at the end of the cup. If that seal is HARD it may very well chip or break if you're careless when putting the cups back on after taking them off.

Those cups have to slide off to get enough room to pull the spider far enough out of the ujoint to separate it. Originally the needle bearings had a sufficient amount of grease packed around them to hold them in position when the cups are slid off the spider, and if yours are still good protect them from dirt and get the cups back onto the spider as quickly as possible and then tape them or tie a rag around the exposed cups so they don't come off, but if they've dried out and fall out or the inside surface of the spider looks scored or dented with parallel lines it's been without grease for too long, get a new u joint. ALSO If you get grit or other crud into the cups it will eventually damage the needle bearings and if even one falls out they're small enough that you may very well lose it, so if you can see any gap or rust in the row of bearings when you look inside before putting it back on, plan on buying and installing a new ujoint.

(Before you button things up for the final time, you might put a small dab of wheel bearing grease into the cups just to be sure that there's enough, unless they have grease fittings, if yours does, grease it after reassembly.)

Now, start with 2 appropriately sized sockets positioned on either side of the cross with a long one on the pushing/tapping side if possible, (because it might get stuck and be harder to extract).

You'll be tapping or squeezing the closer side socket and cup that covers the spider using the smaller diameter socket, while catching/protecting the opposite side cup with the larger diameter one when/if it comes off. This is especially important if you're not using the "C" clamp method.

The socket that you're going to be tapping/squeezing should fit the recess but be as large a diameter as possible to push against the cup so that the cup's surface and the retaining groove don't get damaged. If the retaining groove is damaged the clip may not go in at all or may not seat fully and could fly out right away or sometime later. If tat clip comes out the cup will work it's way outboard further out on the cross and eventually fall off. Method of choice is a very large "C" clamp to squeeze with, and the second method is to tap the socket with a SOFT FACED hammer or a mallet. If you have an extension that fits into an upside down socket without protruding this gives more surface contact and spreads out the impact. If not, impact sockets usually have much thicker walls.

So finally up to the front pump.

Remove the 2 bolts holding the pump bracket to the frame.

Disconnect the wire connectors, one OEM type just slides off, others need to be pried apart.

Disconnect the fuel line fittings and have a rag around it-some from the fuel lines gas WILL come out, usually not more than an ounce.

Do your testing of the pump now that you can see what you're doing.

Remove pump from bracket if not reusing it.

Reverse the process to install.

Ford used at least 2 different types of fuel line connectors, so make SURE you can tell which one is used on yours, because one requires using a special insertion-type tool to open the connector. The other one can be pried back far enough to pull the line from the fitting or fitting from pump. by using a small screwdriver. If you DON'T use that tool on the fittings that require it you have a very good chance of CREATING a gas leakage problem after reinstallation of the old or installing the new pump.

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The back pump requires a different level of commitment.

The Bronco2 repair books always say to lower the tank to remove and install in-tank fuel pumps. You can read up on that in lots of places.

The alternate way to replace the Bronco 2's tank-mounted fuel pump is to leave the tank in place and to cut a hole in the cabin floor for access, but that requires you to repair and seal the hole afterwards. If you cut a reasonably sized hole the repair doesn't HAVE to be structurally strong in that area-but it should be sealed against rusting and restored enough to make it water tight.

For some people this is a much better option as it doesn't require crawling around underneath and dealing with the problems associated with removal and installation of the tank and it's possibly rusty surroundings.

You'd be working around gasoline in liquid and gaseous forms, so care is required to avoid sparking when cutting the hole and a non-welded repair of the hole is what most people should attempt.

When I did ours, after approximately locating the pump's position from below I drilled 4 fairly large corner holes with DEPTH MARKED DRILL BITS and used a SHORT metal cutting blade (set up in such a way as to not be able to penetrate very far below the surface) to cut out a single piece of the floor metal approximately that was about 7 " on a side, possibly smaller. (The hole would not have to be that big if YOU get lucky and happen to end up perfectly centered over the pump retaining ring, but this gave me some leeway) You also need to be VERY careful with both drilling and cutting the sheet metal floor as there may be only about 1" of safe working space below the metal and above the tank. And about possibly cutting yourself on the edges of the hole.

If done that way it's not beyond the skill set of many backyard fixer upper types and you'll have most of the patch premade-or at least a pattern if you're ambitious and want to just shape a bigger metal one to bridge the hole.

The easiest repair would be to use the removed piece as a "scaffold" held in place by short sheet metal screws, while layering fiberglass cloth and resin over the area, extending the fiberglass a few inches wider than the actual opening of course. This will be fine for most people- both watertight and reasonably strong if done well. I chose to do a tougher repair, because I needed the floor to be very strong against possible penetration damage from potentially dropping heavy things like tool boxes on that area.

Plan to cut out the area depending on how you're going to fix it afterwards. For fiberglassing it's not as critical because the patched area will still have a low profile afterwards.

I cut it so that the hole had "high" areas of the ribbed floor on the top and bottom edges of the hole I cut, but that was because I used 2 long pieces and one slightly shorter of 1/8 or maybe 3/16" x approx 1-1/4" bar stock to strengthen the hole, bolted those in place sideways (working through the hole), overlapping the front and back edges of the hole, securing the bars with short CARRIAGE bolts (flattened round heads) using locknuts from below. This required squaring the drilled holes slightly.

The width of steel that I used nestled into the "ribs" of the floor's metal. (The longer supports were long enough to extend about 3-4"past each side of the hole.) By not bolting the center bar into position yet, I was still able to lay and remove safety shielding from sparks under the floor. I clamped the already-bolted top and bottom pieces tightly against the floor metal and tack welded ONLY the outer 2 to the hole edges as further stiffener, ground them smooth, and ran a bead of silicone around the hole's edge and let it partially set up before laying the cutout in place and securing it with only a couple of short sheet metal screws. I put down another layer of waterproof sealer and painted the surface with rust barrier paint, because I'd decided to not seal the floor with fiberglass-to make it easier if future access was ever necessary.

By using carriage bolts, even though the heads are above the highest level of the original floor, the carpeting on top makes them nearly undetectable.