fuel pump rebuild
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- 356 Fan
- Posts: 102
- Joined: Sun Apr 27, 2008 2:20 am
- Location: San Francisco, CA
Re: fuel pump rebuild
Just an update. Used a 2mm longer bolt with the thick black gasket AND also installed a new pump cap (old one was definitely distorted where bolt head rests). For now, it's tight as a drum. No leaks at all. Something interesting that I noticed when I removed the cap with the new thick black gasket, AFTER it was exposed to fuel inside the pump. I noticed that the black gasket swells/grows after being exposed to gas. How did I notice this? Well I took a new black gasket out of another pump rebuild kit and compared it to the new one I installed in the pump cap and the diameter of the gasket was noticeably a bit larger than the fresh gasket. So...while the gasket is definitely too thick, the material it's made of appears to expand when exposed to gasoline and makes sense it would then provide a nice seal.
I still purchased a couple of MIL spec thinner cork gaskets from type356a.com, but for now my pump leak problems are resolved.
I still purchased a couple of MIL spec thinner cork gaskets from type356a.com, but for now my pump leak problems are resolved.
- Jim Clement
- 356 Fan
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- Tag: 1957 356 A Coupe
- Location: Calgary Alberta
Re: fuel pump rebuild
here are some picks of a rebuilt fuel pump..
the main housing needed some machine work to accept the new valve.. then all worked well.
also shows the gaskets that were installed.
this is for an A car
the main housing needed some machine work to accept the new valve.. then all worked well.
also shows the gaskets that were installed.
this is for an A car
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- 356 Fan
- Posts: 32
- Joined: Fri Jul 01, 2011 10:28 am
Re: fuel pump rebuild
ok - 5 years later on the post but i have a 356SC pump leaking a lot of fuel from the dome. Now this had a rebuild in 2018 - so maybe a 1000miles on this car since then - don't shame me! but we do have a primer pump at the front of the car that we use to fill the carbs up before we prime via the accelerator and then start the car when cold. Does anyone think the primer pump is hurting the main fuel pump - maybe putting too much pressure in there?
Shelter Island, NY
1964 356SC Coupe
1964 356SC Coupe
- Martin Benade
- 356 Fan
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- Joined: Wed Nov 23, 2011 10:52 am
- Location: Cleveland, Ohio
Re: fuel pump rebuild
No, but the dome either needs new gaskets, or has been over tightened at some point and bottoms out before squeezing the bottom gasket tightly. The dome is available separately.
Cleveland Ohio
62 Cabriolet
56 VW
02 IS 300
04 Sienna
62 Cabriolet
56 VW
02 IS 300
04 Sienna
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- 356 Fan
- Posts: 32
- Joined: Fri Jul 01, 2011 10:28 am
Re: fuel pump rebuild
thank you! going to do this weekend!Martin Benade wrote: ↑Fri Jul 29, 2022 10:04 am No, but the dome either needs new gaskets, or has been over tightened at some point and bottoms out before squeezing the bottom gasket tightly. The dome is available separately.
Shelter Island, NY
1964 356SC Coupe
1964 356SC Coupe
- Martin Benade
- 356 Fan
- Posts: 12388
- Joined: Wed Nov 23, 2011 10:52 am
- Location: Cleveland, Ohio
Re: fuel pump rebuild
A slightly deformed dome could be carefully straightened in a press, and might not crack. I straightened mine with some sockets in a vice, I don’t recommend that. I ended up with a couple of tiny radial cracks, so far the center gasket is sealing them.
Cleveland Ohio
62 Cabriolet
56 VW
02 IS 300
04 Sienna
62 Cabriolet
56 VW
02 IS 300
04 Sienna
- Graeme Langford
- 356 Fan
- Posts: 278
- Joined: Tue Jul 07, 2020 5:45 pm
- Location: United Kingdom
Re: fuel pump rebuild
I had to buy a new replacement dome as my dome was leaking and even a second hand replacement did not seal up properly
1958 356A
1967 911S
1967 911S
- Wes Bender
- 356 Fan
- Posts: 4940
- Joined: Wed Aug 27, 2008 10:54 am
- Location: Somewhere in the Gadsden Purchase, USA
Re: fuel pump rebuild
They're very much like the jet covers on Zeniths. They don't take kindly to over-tightening. As Martin says, if thy're not too distorted so that they crack when re-shaping them, you might get lucky. Only tighten down the retaining bolts on these items to the point that they just seal. Think a twist of the wrist rather than pulling on a wrench.
Some days it's just not worth chewing through the restraints.....
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- 356 Fan
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- Joined: Fri Jul 01, 2011 10:28 am
Re: fuel pump rebuild
OK - so could not wait and did the full rebuild last night following the video https://www.youtube.com/watch?v=AP0gpyDOVAQ and using the stoddard replacement kit.
Once assembled, primed the pump and fuel was coming out from the front cap and where the main valve gasket sits. The one thing i did was use the new springs, which i think i may just put back the old ones to not throw off the pressure, but in the video they machine the edges to create a new surface around the main valve gasket, is this necessary or can i do something else and do the screws need to be tight? I was able to tighten slightly the front dome and that stopped leaking but continued at the main joint. Also can i use the same gasket from last night, took forever for the kit to come in. Any advice would be great. Thank you so much!!!
Once assembled, primed the pump and fuel was coming out from the front cap and where the main valve gasket sits. The one thing i did was use the new springs, which i think i may just put back the old ones to not throw off the pressure, but in the video they machine the edges to create a new surface around the main valve gasket, is this necessary or can i do something else and do the screws need to be tight? I was able to tighten slightly the front dome and that stopped leaking but continued at the main joint. Also can i use the same gasket from last night, took forever for the kit to come in. Any advice would be great. Thank you so much!!!
Shelter Island, NY
1964 356SC Coupe
1964 356SC Coupe
- Bruce Smith
- 356 Fan
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Re: fuel pump rebuild
Kim-
All mating surfaces should be flattened prior to assembly. Not sure what you're calling the front cap or the main valve gasket. All valve seats need to be able to seal, and all screws tightened. A pic of your problem area may help.
All mating surfaces should be flattened prior to assembly. Not sure what you're calling the front cap or the main valve gasket. All valve seats need to be able to seal, and all screws tightened. A pic of your problem area may help.
Bruce Smith
- Michael Branning
- Registry Trustee
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Re: fuel pump rebuild
Besides getting answers to direct questions here, another resource that's pretty new is the website document library search. Log in and access the Document Search under the Technical Menu. Direct link: https://porsche356registry.org/content. ... _id=579966
You can find detailed articles from the magazine.
Click on the titles to pop up a description of each article, click on the green arrow to download the PDF.
You can find detailed articles from the magazine.
Click on the titles to pop up a description of each article, click on the green arrow to download the PDF.
Michael Branning
356 Registry Vice President/Trustee
'64 SR Coupe
61 S90 Roadster
356 Registry Vice President/Trustee
'64 SR Coupe
61 S90 Roadster
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- 356 Fan
- Posts: 32
- Joined: Fri Jul 01, 2011 10:28 am
Re: fuel pump rebuild
Two more questions - i will rebuild - being that its only been 24hrs - is it ok to use the same rebuild kit? I see no damage since taking it off.
One more questions - the cap its self - there were some old gasket remnants which i scraped off - but could i use a flat sanding process on that as well.
Thank you so much for your support - the documentation is fantastic!
One more questions - the cap its self - there were some old gasket remnants which i scraped off - but could i use a flat sanding process on that as well.
Thank you so much for your support - the documentation is fantastic!
Shelter Island, NY
1964 356SC Coupe
1964 356SC Coupe
- Martin Benade
- 356 Fan
- Posts: 12388
- Joined: Wed Nov 23, 2011 10:52 am
- Location: Cleveland, Ohio
Re: fuel pump rebuild
I think what you are calling the main gasket is the pump diaphragm although it seals too. Did you put some pressure on the pushrod part while tightening the screws? You can flatten its mating surfaces on a piece of 220 grit sandpaper on a piece of glass or a iron table saw table. I think reusing the old springs is reasonable but the new ones are close enough not to cause leaks from fuel pressure.
Your new kit should be fine, and a bit of sanding could be done on the cover, but mostly get it clean.
Your new kit should be fine, and a bit of sanding could be done on the cover, but mostly get it clean.
Cleveland Ohio
62 Cabriolet
56 VW
02 IS 300
04 Sienna
62 Cabriolet
56 VW
02 IS 300
04 Sienna
- Jon Schmid
- 356 Fan
- Posts: 1801
- Joined: Thu Jun 26, 2008 4:32 pm
- Location: La Mirada, CA
Re: fuel pump rebuild
Be very careful tightening the bolt that affixes the dome to the fuel pump body. The body material is made of butter, not guns. Don't ask me how I know...
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- 356 Fan
- Posts: 32
- Joined: Fri Jul 01, 2011 10:28 am
Re: fuel pump rebuild
Thank you - so i sanded with some great 500/1000 paper on a flat surface and they have no light coming through, they make a cupping sound when put together - also did the same for the dome - was actually fun. Last question - the new gasket/valve piece - is it ok to use when it splits? this is not allowing me to upload a pic. the old one looks fine and does not split.
Also - the piece that attached to the engine block - is there a top and bottom - i never ID'd it. it looks interchangeable thank you again!!!
Also - the piece that attached to the engine block - is there a top and bottom - i never ID'd it. it looks interchangeable thank you again!!!
Shelter Island, NY
1964 356SC Coupe
1964 356SC Coupe