August 20, 2014, Wednesday, 231

Rebuilding a fuel pump

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by Anton


INTRO

let's start with what you will need in order to rebuild a fuel pump

1) fuel pump of course

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2) rebuild kit as you might have guest it, you can get them from WW [1]

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this is what you will find in the box 2180639425_e50e6c6a27.jpg

3) and a jig to assemble 2194294488_c0710c1ac7.jpg

(A good friend of mine made this one for me ;) ) instructions on how to make one out of block of wood on TS:

http://www.thesamba.com/vw/forum/viewtopic.php?t=107797

TEARDOWN

Now that we have everything in hand let's start by disassembling.

Take 4 screws from the top and remove the cover 2193374950_a974e3f345.jpg

Here you should find a spring, membrane and a paper gasket. Go ahead and remove the membrane. If it's stuck carefully pry it off with a small screwdriver.

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here we gave top part disassembled: 2192588241_545d8f0d61.jpg

Let's move on to the fuel filter located at the back of the pump (back/rear of the car). You will need 14mm wrench to remove the plug holding the filter.

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After plug is removed you should see the filter. It an orange plastic cone with screen mesh.

Note that the plug has a aluminum washer just like plugs on carburators. This washer will be replaced with fiber kind from the kit. 2192590613_0cafdab7e4.jpg

Here is a nice shot of the filter. Remember to save it!

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Now let's proceed with separating fuel pump halfs. All you have to do is remove 6 screws. 2193361732_3e62018b49.jpg

In my case it felt like this pump belonged on Hulk's car because halfs did not want to separate and needed to be persuaded with some gentle bumping on the edge.

After you have separated the halfs you are faced with a second diaphragm. Don't try to remove it just yet because it is held in by the arm.

Let's go ahead and remove pivot shaft from the arm. If you are rebuilding brazilan pump it won't have clips on the shaft. You need to find side that has pin marks and drift it out from the opposite side.

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The reason behind this is because one opening in the fuel pump base is larger than the other.

Shaft is out and you can go ahead remove spring, and slide arm out from the diaphragm. 2193363420_be95a0e73a.jpg

Now diaphragm is free and can be removed.

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Take a look at the check valve in the top part of the fuel pump. 2192580063_d00c64e6b0.jpg 2193366376_ebeb4773c9.jpg

Fiber circle should move a little bit and spring should be nice and clean. Most likely it will be ok, if not you can remove pressed in part and replace it with the one that comes in a kit. Replacement will not fit brazilian pumps only german. If you do replace it, you will have to ping it into place.

Now that you have every thing apart put pump body, screws and fuel filter plug into mineral spirits for a good soak.

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INSPECTION

after everything has soaked for about a day, you can remove your fuel pump from mineral spirits and give pump body a good wash with a brass wire brush.

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Before we start putting everything together let's re-examine a few parts that we got in the kit.

The lever.

Side by side comparison with the one from the pump (right) 2194249988_dbbdbfc262.jpg

it doesn't even look like a finished product. 2194250786_5a284107d4.jpg

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Now the original from the pump:

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close up of lever where it meets the pushrod 2193468779_f257f911cb.jpg

To smooth it out I spent a few minutes with 360 grit sand paper and finished it up with 600 grit.

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ASSEMBLY

Now here is where the fun begins.

Start by setting the pin on one side just enough to go through the wall.

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Here it is ready to for lever. 2194161308_8e269494b4.jpg

This is how the arm connects to the shaft of the diaphragm. Visualize this so you know what you need to do to get them connected inside the pump.

lever is supposed be sitting under white plastic washer. Otherwise lever and diaphragm rod end will wear out in no time.

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You could try installing diaphragm and lever together, but it won't work. There won't be enough clearance to get the spring back under the lever.

Simply put the diaphragm into the bottom part of the fuel pump body. 2194232410_82bb280d78.jpg


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Press it down with one hand and slide the arm onto the shaft of the diaphragm.

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Don't put pivot shaft into final position just yet. Now is the time to install the spring:

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I've used 2 jewelers screwdrivers to guide spring into it's position.

Press it down and position it under the lever onto the dimple.

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This is one shot that shows how I am holding lever in general position while tackling spring into place.


You are on the final stretch of bottom part assembly.

Lets reexamine what is going on in this shot besides the point that I have 3 arms...

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My left thumb is pressing down on the diaphragm, while I am holding the pump with my left index, right thumb and middle fingers. And my right index finger is holding lever in position. And this whole circus trick is so that my left middle finger can press in the shaft.

Once you have this trick worked out put the cir-clips onto the ends of the shaft. If you are rebuilding a brazilian pump you have just upgraded it to a better pivot shaft!

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Go ahead and mount bottom part onto the jig. As you can see I am way ahead of you since my clips are on the pump and it's already mounted.

Now let's turn our attention to the top part. Go ahead and install second check valve. Remember the shiny thing has a bend toward the pump and brass looking outward.

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Straighten out diaphragm and turn it so all holes align. Put the top on and replace 6 large screws. Don't over tighten and don't forget to put lock washers under the screws. If you tighten screws too much you will bend top and bottom parts. Let's face it nobody likes fuel leaks so let's not warp sealing surfaces here.

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Drop the top diaphragm on.

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Follow it with a paper gasket.

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New spring from the kit. 2194241356_144b639082.jpg

least but not last the top cover. 2194242246_ba22cd9d2c.jpg

Press it down and reinstall 4 small screws with lock washers. 2194243250_70d4fae374.jpg

Finish it up with new fuel screen.

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Secure it with plug and new washer from the kit

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14 mm wrench or socket to tighten it up

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And finally we are done. 2194247026_d12d0d2f0d.jpg

One thing I want to mention is fuel pumps are made out of pot metal and are very easy to warp, or strip out threads, so don't go over board when putting it all together. If your pump half's don't line up right, take out 360 grit sand paper and place it on top of piece of glass. Put paper and glass into a tray filled with water and sand it flat. Water lubricates while glass is somewhat near perfect flat surface.


INSTALL

not so much as step by step instructions on how to install, but rather how shimming affects fuel pressure. Enjoy. Sorry for sideways clip and last one is kinda dark. But isn't working on the car during sunset is the best time???

http://www.youtube.com/watch?v=7TYk5w_opXs


More images can be found here: http://www.flickr.com/photos/volksnut/sets/72157603721798314/