Author Topic: Original Glass-Bowl AC Fuel Pump Rebuilt  (Read 1409 times)

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Offline 3929R

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Original Glass-Bowl AC Fuel Pump Rebuilt
« on: Wednesday,April 17, 2019, 09:44:12 PM »
For the first time in years, when I tried to wake my Europa from it's winter's nap it would not start. The original fuel pump was kaput. I considered going electric or getting a replacement mechanical pump, but the original glass bowl pump looks so damn cool that I thought I'd try to rebuild it.

I used this kit from R.D. -

The rebuild was simple and straightforward with the exception of removing the old valves, which were pressed and peened/stamped into the pump housing. I used this site for guidance in removing the old valves - http://www.74tr6.com/fuelpump.htm

On the valve in the center I used a Dremel to remove the peened down tabs that held the valve in. On the valve to the side I found I could break off the peened down tabs with a small flat-blade screw driver. I used the same small screw driver to drive out the side valve from the top side of the pump housing (I did not have a punch that would fit).

The centered valve needed to be extracted. The diaphragm mechanism was easy to pry out in pieces, which left a hole that I tried running a 7/16" tap through. However this did not work as the valve is pressed together such that its center would rotate with the tap. I then drilled out the center hole so that a 1/2" lag bolt could be snugly threaded into it (there was plenty of depth behind the valve). I then used the 1/2" lag bolt with a very large fender washer to extract the valve - see link above for pictures and a better explanation (I used a fender washer instead of rectangular bar stock).

To press in the new valves (I didn't forget the gaskets) I used a short scrap of pipe (ski pole), since my sockets had too thick of a wall. I used the pipe and a hammer to tap them in.

Once the pump was primed the car fired right up and runs better than it did in the fall! I should have rebuilt it sooner.

So far no leaks onto the starter.  ;)

I hope this description makes sense and is of use to someone.
« Last Edit: Wednesday,April 17, 2019, 09:47:37 PM by 3929R »
Mark
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Offline Certified Lotus

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Re: Original Glass-Bowl AC Fuel Pump Rebuilt
« Reply #1 on: Thursday,April 18, 2019, 03:05:33 AM »
Nice work and great explanation, thanks!

Offline tedtaylor

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Re: Original Glass-Bowl AC Fuel Pump Rebuilt
« Reply #2 on: Thursday,April 18, 2019, 06:24:49 AM »
EXCELLENT.   It makes me very happy when owners stick to original design.   Others would be quick to change over to an electric fuel pump, but why?   The original equipment works so well for such a long time, why not replace, repair or rebuild?
Same goes with the brake boosters.  Many owners avoid the hassle, toss them and make other modifications to compensate for what otherwise was perfectly fine.    Stop taking short cuts and the quick and easy way out, take the time to research the problem, seek out original equipment and restore them to original.
KUDOS to YOU!!!
TED
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owned nearly 50 Lotus cars over the years!
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Offline Bainford

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Re: Original Glass-Bowl AC Fuel Pump Rebuilt
« Reply #3 on: Thursday,April 18, 2019, 09:20:39 AM »
Thanks for the post, and well done. I had to rebuild mine last spring. Fuel was leaking through the diaphragm where the pull rod penetrated it, such that over the winter slumber over 10 litres of fuel seeped through into the engine sump. When I disassembled my pump I found the boot through which the pull rod passes had a tear. The kit I had ordered from Dave Bean did not have this part in it.

In fact, the boot part, or a kit that included it was proving hard to find. I eventually found a place in the UK called Small Ford Spares that sold a kit which includes the boot. As a confidence inspiring bonus, the valves in the new kit had the same appearance as the originals. Adding an once of prevention, I applied Seal All (a gasoline resistant sealant) around the pull rod where it penetrates the diaphragm to hopefully prevent the sump from filling with fuel again, though it may be totally unnecessary.

As you mentioned, removing the old valves is the tricky bit. Like you, I used a Dremel to remove the retaining stakes, and had to abuse one valve to pluck it out of its bore. Re-staking the new ones went pretty good, given the soft metal (zinc?) of the pump body. As you said, the glass bowl pump has a cool vintage look and needed to be retained. Cheers.
The Twin Cam plays the symphony whilst my right foot conducts the orchestra. At 3800 rpm the Mad Pipe Organ joins in.

Trevor

Offline 3929R

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Re: Original Glass-Bowl AC Fuel Pump Rebuilt
« Reply #4 on: Thursday,April 18, 2019, 10:14:41 AM »
Thanks guys!

...Fuel was leaking through the diaphragm where the pull rod penetrated it, such that over the winter slumber over 10 litres of fuel seeped through into the engine sump. When I disassembled my pump I found the boot through which the pull rod passes had a tear.
I wondered about that seal but shouldn't a new diaphragm prevent fuel from leaking into the base of the pump and past that into the sump? With a good diaphragm I think the boot you replaced would keep engine oil from leaking into the base of the pump, which has a weep hole for the oil to leak out onto the ground. My pull rod boot was not torn but it will likely allow some oil to escape. However, the bottom of my fuel pump was reasonably clean and oil free. I don't think it is a leak point for me.

In fact, the boot part, or a kit that included it was proving hard to find. I eventually found a place in the UK called Small Ford Spares that sold a kit which includes the boot. As a confidence inspiring bonus, the valves in the new kit had the same appearance as the originals. Adding an once of prevention, I applied Seal All (a gasoline resistant sealant) around the pull rod where it penetrates the diaphragm to hopefully prevent the sump from filling with fuel again, though it may be totally unnecessary.

As you mentioned, removing the old valves is the tricky bit. Like you, I used a Dremel to remove the retaining stakes, and had to abuse one valve to pluck it out of its bore. Re-staking the new ones went pretty good, given the soft metal (zinc?) of the pump body. As you said, the glass bowl pump has a cool vintage look and needed to be retained. Cheers.
Good to know. Thanks!
Mark
Salt Lake City, Utah, USA

Offline Bainford

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Re: Original Glass-Bowl AC Fuel Pump Rebuilt
« Reply #5 on: Thursday,April 18, 2019, 12:42:14 PM »
I wondered about that seal but shouldn't a new diaphragm prevent fuel from leaking into the base of the pump and past that into the sump? With a good diaphragm I think the boot you replaced would keep engine oil from leaking into the base of the pump, which has a weep hole for the oil to leak out onto the ground. My pull rod boot was not torn but it will likely allow some oil to escape. However, the bottom of my fuel pump was reasonably clean and oil free. I don't think it is a leak point for me.


Yes, sorry, I didn't mean to infer that the boot seals against leaked fuel. The diaphragm will keep the fuel out of the sump. The boot, as you said, keeps engine oil, etc out of the lower end of the pump. Cheers.
The Twin Cam plays the symphony whilst my right foot conducts the orchestra. At 3800 rpm the Mad Pipe Organ joins in.

Trevor

Offline TCS4605R

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Re: Original Glass-Bowl AC Fuel Pump Rebuilt
« Reply #6 on: Thursday,April 18, 2019, 06:02:18 PM »
I have a problem with the location of the mechanical fuel pump and it’s glass bowl - it is really close to the starter motor.  A fuel leak onto the starter can ignite when you hit the starter button - I have seen it happen on a Europa - not mine luckily.  I have an electric fuel pump mounted just in front of the right rear wheel on the fiberglass with a fuel pressure regulator.  I installed a blanking plate over the old fuel pump hole.  Something to think about.

Tom
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Offline tedtaylor

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Re: Original Glass-Bowl AC Fuel Pump Rebuilt
« Reply #7 on: Thursday,April 18, 2019, 08:21:53 PM »
I have a problem with the location of the mechanical fuel pump and it’s glass bowl - it is really close to the starter motor.  A fuel leak onto the starter can ignite when you hit the starter button - I have seen it happen on a Europa - not mine luckily.  I have an electric fuel pump mounted just in front of the right rear wheel on the fiberglass with a fuel pressure regulator.  I installed a blanking plate over the old fuel pump hole.  Something to think about.

Tom
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I knew a guy with an electric fuel pump mounted just in front of the right rear wheel on the fiberglass that was faulty and overheated and set the fiberglass on fire.    Something else to think about?
 ;D
TED
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Offline jbcollier

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Re: Original Glass-Bowl AC Fuel Pump Rebuilt
« Reply #8 on: Thursday,April 18, 2019, 09:38:23 PM »
Lots of things can fail and cause a fire.  I have seen fuel pressure regulators spray fuel like a fountain.  Keep it simple, change hoses as part of regular maintenance, and carry a fire extinguisher.

Offline Steve_Lindford

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Re: Original Glass-Bowl AC Fuel Pump Rebuilt
« Reply #9 on: Friday,April 19, 2019, 12:35:38 AM »
This was mine before a rebuild with kit. The holes in the diaphragm in the new kit didn't line up and I had to punch new. I am a great believer in originality but I have often flattened my battery waiting for fuel to reach the carbs after a long duration of starting the car. I have been thinking about getting a hand pump (used in boats??) as a primer. I have read that if the tanks had more fuel in them it would solve the problem...

Steve

Offline 4129R

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Re: Original Glass-Bowl AC Fuel Pump Rebuilt
« Reply #10 on: Friday,April 19, 2019, 05:02:09 AM »
My pump filled up without any priming when the tanks were full enough.

Offline jbcollier

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Re: Original Glass-Bowl AC Fuel Pump Rebuilt
« Reply #11 on: Friday,April 19, 2019, 06:22:44 AM »
A good pump should draw fuel up pretty quickly.  Test it, not just pressure output, also vacuum on the suction side.  It should hold a vacuum for a long time as well.

Nothing wrong with fitting an electric pump as long as it is done right.  It should be mounted low and rated at the desired pressure.  Fitting a pressure regulator just adds more potential points of failure.  The pump should also be powered through a safety circuit, either a impact/roll-over switch, or by a relay controlled by engine oil pressure and starter operation.  I prefer the impact/roll switch as that is the simplest and it also allows you to prime the carbs without having to crank the engine.

Offline tedtaylor

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Re: Original Glass-Bowl AC Fuel Pump Rebuilt
« Reply #12 on: Friday,April 19, 2019, 06:56:28 AM »
This was mine before a rebuild with kit. The holes in the diaphragm in the new kit didn't line up and I had to punch new. I am a great believer in originality but I have often flattened my battery waiting for fuel to reach the carbs after a long duration of starting the car. I have been thinking about getting a hand pump (used in boats??) as a primer. I have read that if the tanks had more fuel in them it would solve the problem...

Steve

Ray at RD Ent sells a direct replacement mechanical pump WITH PRIMING LEVER, although pump doesn't have a glass bowl.
TED
"Driving a Lotus is a triumph of bravery over intelligence." Stirling Moss

'13 Evora S
owned nearly 50 Lotus cars over the years!
TaylorMadeClassicCars on WWW and Facebook