Replacing a leaking HydroHot fuel pump

[Bill Sprague]

Several weeks ago Marty saw fuel dripping from their HydroHot.  He determined the fuel pump was leaking.  Thinking that other Beaver owners might benefit from watching a remove and replace procedure, he invited me to shoot a video for this forum.  Marty ordered the parts and we set a date.

Jay, a neighbor and rumored to be a licensed aviation mechanic, was equally interested and joined us.  We enjoyed a few hours together getting it all done.  I had fun learning to shoot with three cameras and trying to make the video more watchable by adding clips from the secondary cameras to a primary video track.  I also had fun experimenting with some special effects.  About two thirds in, Marty is returning the electrode gauge to its storage spot.  None of use would have electric screw guns if our wrists worked like that!  And, I really did make up the ending.  Marty and Suzie's coach did not burn up.

The editing took a few weeks.  During that time Marty has verified there are no leaks and the system runs as it should.

The repair procedure was lengthy enough that the best I could do was get it down to 34 minutes.  If you enjoy mechanics or want a better view of the internal parts of a HydroHot or AquaHot, grab a cup or two of coffee, get a reasonable internet connection and enjoy!

As a bonus, there are a few extra parts where Marty explains setting the electrodes and cleaning the burner tube.  Except for nozzle replacement, he shows what's necessary for a normal service.

Click:  https://vimeo.com/67970941  (Note that on Vimeo there are two "switches" in the lower right corner.  One is "HD".  Click on it to switch from HD to SD if you have a slower connection.  The little four bladed propeller makes it fill your screen.)

[Bob Stone]

Excellent job. If a picture is worth a 1000 words a video is worth at least a million.

I hope I'll never have to replace the fuel pump but if I do, after watching your video, I'd attempt the repair with a lot more confidence.
Thanks a million for sharing your expertese.
Bob

[Bill Sprague]

Excellent job.

Marty has helped me on several Beaver tasks that have all finished well!

[Bill Sprague]

The supplier of the fuel pump reviewed the video and offered some suggestions:  

"I watched video. Pretty good and very helpful although it used up most of my bandwidth allotment for the month.

I would like to make some suggestions.

It is not real clear that you put plastic on the jaws of the vice grips before you pinched off the fuel lines. I had to look carefully.

You clamped off the fuel supply line BOTH at the fuel filter AND at the Webasto. You probably only need to clamp one spot.

First thing I do is to remove the Webasto from the coach by disconnecting the fuel unions on the bottom of the Webasto and disconnecting the thermostat connections. It makes the entire unit much easier to work on up on the bench.

The reason that the high pressure pipe from fuel pump to nozzle tower did not fit, is that you re-used the extension from the old pump. The new pipe screws directly into the fuel pump. Fits perfect and should not need to be bent.

Remove and clean combustion chamber AND inside of combustion chamber on Aqua-Hot with wire brush. The cleaner you get the inside the better the heat transfer.

I would have suggested that you replace the rubber grommets around the fuel pipes. They appeared to be very hard. Did they seal?

I would have suggested that you replace the nozzle, since you had the burner out. Webasto ALWAYS runs better with new nozzle.

If the fuel pump has been leaking for awhile, there may be a quantity of diesel fuel built up in exhaust pipe. Unit will make white smoke until diesel fuel burns off. May take 5-10 minutes. It can be very alarming.... just let it burn off.

Congratulations on your successful repair."

[Orman Claxton]

Hi Marty
When a fuel pump leaks that much, it will wipe out the fan bearings,
If you hear a squealing sound while running,change the bearings as soon as possible, or else the rough bearings will also wipe out the bearing housing.
By the way that is a great film, also good job.

[Bill Sprague]

.....By the way that is a great film, also good job.

Thanks for the compliment Orman!  I had a lot of fun doing it.