Replacing the Fuel Pump: 1990 Southwind, P32

[bgbevan]

This might apply to other 1991, 1992, 1993, P32 Chevy chassis.  1990 is the first year of the TBI carburetion so this won’t apply to 1989 and down.  There is also no regulator and no mechanical fuel pump in the TBI fuel system

I went out to start my coach after it had sat idle for 6 mos and it wouldn’t fire up.  Eventually figured it wasn’t getting any fuel.  I immediately suspected the fuel pump although there are other components in the circuit that can cause the fuel pump to not run....oil pressure switch, fuel pump relay, fuses, etc.  To eliminate all this stuff, have someone switch the ignition on while you listen for the pump.  Ear to the floor boards over the tank, or best, ear to the tank underneath.  After I determined the pump was running, I pulled the in-line filter located along the R-side frame rail and slipped a 5’ clear plastic hose over the steel output line from the tank/pump and stuck the other end a small gas can.  When I would turn the key ON, a little bit of gas would flow but if I raised the plastic line up(cheap version of pressure gauge), the gas would only rise a few inches above the resting level in the tank.  I reasoned that a 10 psi pump should be able to pump the gas up the tube until it weighed 10 lbs.  Since I could hear the pump running by putting my ear to the back floor boards and/or the tank itself, I had ruled out anything in the circuitry.  At this point, I knew the fuel pump was going to need replacing.  Ugh!  (I think the earlier coaches(1989 & down) had an in-tank pump along with a mechanical pump on the engine.)  My coach had a 60 gal tank with about 20 gals of gas inside.  I cruised a lot of blogs and forums and picked up a few tidbits of information before I started the job.  There was an interesting article @ http://www.classicwinnebagos.com/forum/index.php/topic,8914.msg44460.html#msg44460 and a pic posted by MadTrap showing a defective fuel pump.

Here’s a few tips to get you started and I’ll try to hit the high spots along the way.  It would be a relatively straight forward process to drop the tank, but 25 years of dirt and rust creates some interesting issues.  Put a big tarp down under the rear area.  A lot of dirt is going to fall down and you’re going to spill some gas.

Here are some extra tools and other stuff you should have that may not be in your collection.

- Fuel pump, mine was #E3268.  I used Airtex but there are other name brands.  ~$30 on eBay or $45-$50 at AutoZone or O’Reilly’s
- Floor jack(small)
- Bottle jack, 10 ton
- Axle/jack stand(s), 6 ton.  ~$40 @ Harbor Freight
- 5/8” flare/tube "socket" wrench, 3/8 drive @ NAPA or Harbor Freight
- 1/4” ratchet/socket set
- Rust penetrant, a good inexpensive concoction is a 50/50 mix of Acetone and Mercon ATF. Just put it in a spray bottle and have it at the ready.  Shake well.
- 1/2” ratchet/socket set is ideal but I got by with a 3/8” set.
- 3/8” hex socket and a 1/2” or 3/8” breaker bar
- Drain hose, 3’ clear plastic hose and a 1/2” to barb adapter so the hose will slip fit on the barb end.  ~$2 plastic @ Lowes
- 5-6 gal Jerry cans for gas storage
- New hanger bolts, 24” x 3/8” All-Thread stock and misc nuts and washers.  ~$20 @ Lowes.

First drain the gas out of the tank.  Sounds easy enough.  Safety first: No heating, pounding, or switching on/off of shop lights.  No sparks.  If the pump works at all, you can get some of the gas out that way.  The more gas you leave in the tank the heavier and more unwieldy the tank.  With all the gas drained the tank weighs 75 lb or so and 5-6 gals of leftover gas adds another 40 lb or so.  Proceed at your own risk using my draining process.  I had a fire extinguisher nearby just in case.  I jacked up the R rear axle and put it on a jack stand, which tilts the tank to the left.  There is a 1/2” steel drain plug with a hex drive on the L-front of the tank.  It’s probably rusted in and I think they used some kind of sealer when it was manufactured.  Don’t use heat or any pounding to get this loose.  Slather it with penetrant first and patiently try to rock it back forth to break it loose.  May take an hour or so or an overnight soaking in penetrant.  Once you break it, the next step is tricky.  You want to back out the plug and simultaneously screw in the 1/2” plastic adapter with the 3’ of hose.  Have the other end of the hose pinched off and/or stuck in to a 2 gal gas container.  PATIENCE here and even a helper would be good.  You’re going to spill some gas so have an oil pan under the drain plug area.  If you make it this far, it’s just a process of filling the small gas can and transferring it somewhere else.

Dropping the tank is relatively straight forward except for the 25 years of dirt and rust.  Get the floor jack centered under the tank.  I cut a 19” x 24” board that fits between the hanger brackets and centered the jack under it.  Put the jack up snug so you can get the hanger bolts out.  I wasted a lot of time with penetrant and trying to back the bolts out, and in the end, I cut them all off with a hacksaw.  But before you cut them, break the bolts loose from the frame.  The nuts for the bolts are tack welded on to the frame rail and you can’t get a wrench on them.  Break the bolts from the tack weld using a big bar and wrench on the bolts till the nuts break loose.  Cut the bolts off with a hacksaw with an inch or less hanging through the frame rail.  You’re going to replace these bolts with new all-thread hanger bolts.  You can save the flat washers if you like.

Now that you’ve got the tank hanger assembly removed, disconnect the hoses you can get at.  The rear filler, rear vent hose, canister hose, etc.  You will probably have to cut the filler(2”) and the vent(3/4”) hoses because there was some kind of sealer that made it impossible to break them loose.  Oh well, there goes $35 down the drain.  Now you can start to lower the tank so you can disconnect the other stuff.  Let the tank down a little so you can get it centered on the jack and push it back so the filler flange clears a rear brace.  It’s a tight fit.  Now lower the tank a couple of inches below the frame rail until you start to see the fuel pump connections(R side).  There’s some flex in the rubber feed and return hoses, and just enough room to get some wrenches on the flare nuts.  These steel nuts are probably rusted.  (I couldn’t get the feed line(bigger) flare nut loose and eventually had to cut it with a hacksaw.)  I recommend soaking the nut(s) overnight in the special penetrant by jury rigging some sandwich bags so the nut is completely immersed in the penetrant.  This where you will need the flare nut ratchet or breaker bar combination and a 3/4” box or crescent on the receiver nut.  If you’re lucky, you will get both nuts to break.  If you’re unlucky like me, you’ll have to cut the line flush with the nut.  When you do this, you can drop the hose and get a 5/8” hex socket on the flare nut to break it out.  If you cut the line, you’ll need to splice on a new end.  It’s called a “GM flare” and nobody in town will know what it is.  It’s not a single, double, or bubble flare.  Also, nobody in town will have the tool(Mastercool) that can make the flare so it’s best to just get the splice kit.  The patch kit is available at AutoZone or eBay, Dorman #800-153.  Do some careful measuring here.  Compensating for the union, you can extend the flared end 1” or less(see pic).  It needs to clear the frame rail when raising the tank.  On the L-side of the tank, disconnect the fuel line to the generator and the electrical connector to the pump.  Now you should be able to drop the tank all the way.  I put a couple of 8’ 2x4s as sliders to take the tank out the back.

Now you have the tank out and can get the pump out.  I would hose all the dirt off with water, especially around the holding ring.  The holding ring has some ears that should be bent flat and the ring loosens by turning CW(rear end backwards).  With the ring off, lift the pump and gauge-float assembly out of the tank.  Be careful not to let a bunch of dirt drop in to the tank.  I used a shop vac while cleaning around the mouth with a small wire brush.  If you do drop dirt in, get someone with a small hand/arm to wipe it out with a paper towel.  It’s highly probable that the 2” rubber hose that connects the pump the to outlet, has deteriorated and sprung a leak.  Probably a $.50 part.  The pump is probably OK but since you’ve come this far, replace it with the new one.  If you use an Airtex pump, you’ll need to get a new strainer sock that fits on the end.  AutoZone #FS1 for the E3268.  I used silicon grease on/around the the O-Ring.  The O-Ring in my kit was slightly bigger than the flange channel so I ended up cleaning and using the original one.

Now install the new hanger bolts.  I used 3/8” stock cut to 13”-14”.  Starting from the top, the sequence down the All-Thread is nut>frame rail>lock washer>nut>tank>flat washer>lock washer>nut.  Now just reverse the process by putting every thing back where it came from.  You can manhandle the tank into place but an extra hand would be helpful here.  Get it centered and back on the floor jack and slowly raise it back in to place.  Take it slow and easy  and make sure nothing is going to get pinched when tank is tightened all the way up. There’s a vent hose coming from L-center of the tank, that needs to go over the top of the upper pad bracket.  Connect the fuel pump feed hoses and finally the rear filler hoses.  Every thing is pretty straight forward here.  Once you get the brackets under the tank and semi-tightened down and before removing the floor jack, I put gas in the tank and did a little test sequence to make sure it was pumping.  If the R-side jack stand is still in place, you’ll need 8-10 gals or so to get gas to the pump pickup.  If you still have the in-line filter out, you can use the plastic hose to see if the pump is pumping.  If it is, then put the filter back in.  Now turn the key on a few times so the line will charge up and start the engine.

You will probably notice the coach runs a lot stronger because that pump probably failed over time and starved the engine of gas slowly but surely.

This took me 3-4 on and off days to complete because had to shag a lot of tools and parts.  Could do it easy in a day now.  Hope this helps someone with the same problem and saves a few hours and a few buck$.

Bill Bevan


Picture #1: Tank is supported by a small floor jack and has been dropped far enough to disconnect the 3 steel lines to the fuel pump.  These lines are located on the left/front side of the tank.


Picture #2: The problem.  Shows a short rubber hose that connects the output of the fuel pump the steel line coming out of the tank.  A $.50 part brings down the whole fuel delivery system.


Picture #3: The input/output lines from the fuel pump showing the spliced replacement line.  The output line was cut during the disassembly because the steel flare nut was rusted/frozen.


Picture #4: Top item shows the 3/8" drive flare nut socket installed on a breaker bar to get maximum leverage on the steel flare nuts on the tank connections.  Bottom item shows the patch line with the "GM flare" you will need to install if you have to cut the lines.