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Fri Jun 26, 2015 10:53 pm

This thread is dedicated to information on 25hp and 36hp fuel pumps.

Please post in this thread if you have an corrections or additional information or photos or any questions.

Split Beetle
8mm flat top

Zwitter
6mm flat top
Used from:
Bug: 1 Oct. 52 / Chassis # 1-0397023
Bus: 2 Jan. 53 / Chassis # 20-041712

Oval Window - 1958
54-55 6mm wavy top with screw in bottom 1/2

"55 only" 6mm wavy top with no screw in bottom 1/2
Exact Introduction date unknown, mid-1955 at some point
It has been be narrowed down to between May and October, 1955. More info needed

This is original Bus engine # 20-1251855 (December, 1955)

56-58 6mm pump with ribbed top
Used from 15 Feb. 56

58 only(?) - Similar pump to above but with longer outlet:

Information from Progressive Refinements:

59-60
58-60 with filter in top

When was the filter added?
Progressive Refinements states:
8 Dec. 58
Chassis# 417 115 (Note: Bus VIN #)
Engine # 2 680 764
Fuel Pump - Now: synthetic filter

Reference photos of most (all?) of the fuel pump versions:

Thanks to hazetguy for many of these photos.

Sat Jun 27, 2015 9:12 am

Thanks for posting that up for us Everett! Fantastic, nice photos too (Thanks to John for some of those photos).

I was digging thru my extra 25- and 36bhp fuel pumps and I think I have at least one of almost every one you showed. I noticed the serial numbers stamped into the halves, and I figured that they would ascend in number as they got newer and according to your new pump page they seem to do that (with only one exception in my pump collection). In terms of a data point in time, I can only suggest one serial number and the production date of the Beetle it came on. My all original June 22nd, 1955 production Deluxe Sunroof Beetle with fairly unmolested motor came with fuel pump serial #1475466. Also several of my German late '59 and onward 36bhp fuel pumps with the "bolt/filter" top had serial #s and several had none at all? Go figure...

It might be interesting for others who can pretty much confirm an "original" pump still with its' original motor/VW vehicle to post the info here.

Thanks again for creating the breakdown of 25- and 36bhp fuel pumps and their modifications over time!

Bill Bowman

p.s. I wonder if that '58-only pump with the taller output casting necessitated an shorter fuel line from the pump to the carb inlet, although I imagine that they just bent the soft line to accommodate the taller pump...

Sat Jun 27, 2015 9:23 am

Yes, a lot of the photos above are from Hazetguy.
He is usually one of my go-to people for finding good reference photos.

The "58-only" thing is a guess - corrections and more information welcome.

Yes, the serial numbers are sequential from what I have seen.

I agree it would be interested to have some sort of reference point for the serial numbers, if people have known original pumps.

Regarding your mismatch:
Many pumps have had the bottom half replaced due to wear.
For instance, I have several 54-55 wavy top fuel pumps that have later bottom halves.
The bottom half is the part with the serial number so this could cause confusion if you are trying to use the serial number as some sort of production date reference.
This is probably the case with the one exception you found in your collection.

Mon Jun 29, 2015 3:20 am

very educational...thankyou

Fri Jul 03, 2015 12:07 pm

BulliBill wrote:
...It might be interesting for others who can pretty much confirm an "original" pump still with its' original motor/VW vehicle to post the info here...

December 1954: 1303153 (wavy top w/drain screw).

I also have one of those pumps with the out-of-sequence serial numbers. It's the 1956-58 ribbed top style w/serial #578618. The stamp set used is larger and the number's located just to the left of the inlet port (not the usual location). I see no evidence of an old serial number in the usual location on the flange.

Fri Jul 03, 2015 5:10 pm

I love this thread. It should be a sticky. :vw:

Sat Jul 04, 2015 6:12 am

If by "sticky" you mean putting the thread in the Oval Beetle FAQ section, it is the top topic under "fuel system" in the Oval FAQ. Maybe I don't know what a "sticky" is?

This is a very informative thread!

Bill

Thu Jul 23, 2015 2:33 pm

It's interesting that the diagram for the "56-58 6mm pump with ribbed top
Used from 15 Feb. 56" shows the screw on the bottom half. I thought the screw was discontinued by then (it's missing from the 55 only pics above it). Was it reintroduced for a short period? I ask because I have an 11/55 (1956) beetle that has the later top with the filter, but the bottom has the large screw. Is this an early bottom with a later top?

Thu Jul 23, 2015 5:04 pm

Yes, that is strange that the parts book shows things that way.

As far as I know the screw was discontinued in early 1955.

Sun Feb 21, 2016 7:42 pm

so im reading this trying to see what style is correct for my car, must have went through it a few times before i notice the pic of the "58" only pump is a picture taken by me in my shop ! im sitting here reading it and the pump is right here next to me ! not sure what yr it is actually but the serial # is 3189654

Mon Feb 22, 2016 11:41 am

That's funny! Sue for copyright infringement and buy 1 of every pump.

Sun Feb 28, 2016 4:50 pm

So im building a new motor for my 58 . I should be looking for the long outlet fuel pump or the one with the shorter outlet ?

Mon Feb 29, 2016 6:06 pm

Great thread, thanks

here are the two fuel pumps that came with my 56 vert

any idea what year the one on the right is from?

also, assuming there are rebuild kits for the left one?

Mon Feb 29, 2016 11:11 pm

Yes on the kit.

The right one is 59-60 since it has the filter.
I can't tell if it's German or aftermarket though.
Either way, it's later.

Thu Dec 07, 2017 8:09 am

Hi guys,

I thought it's time to be a bit picky and showing other minor differnces that I discovered on my fuel pumps.
1. KDF and 8mm 25hp fuel pump tops ARE NOT identical and the screw in the lower part too.

2. there are different early lower parts, at least two different versions. One has the sign "Deutsche Vergaser Gesellschaft" and the other one "SOLEX". I thought this could be the differnce between 25hp and 54/55 only, but I have engines as references to refute that. These engines still have the correct fuel pumps since the day of leaving the factory, I'm 100% sure.

Guess the most interesting differnce I noticed are the tops between 54/ early 55 and late 55-58.
They all have the "wavy" top, but if you once saw the differnce, you won't forget :D

The shape of the areas between the screw holes is completely different. If you compare the tops with a 25hp pump and 58-60 filter fuel pump, we can conclude:
54/55 with the screw in the bottom should have the top that looks simliar to 25hp, it has the wavy top, but the shape between the holes is identical to 25hp, there are no "dividing fins". From 55 (base with casted screw support, but no screw anymore) the wavy top appears to have the same shape as the latest 36hp fuel pump versions.

Hope my pictures illsutrate that. The pumps I'm reffering to never received another top.

Regards,
Jan

PS: if someone has a HUF fuel pump, I'm in need of one...

Thu Dec 07, 2017 9:19 am

Thanks for posting more information.

I think the pump on the left here has had the top replaced:
56samba wrote:
This is what I have seen many times for pumps with no screw in the bottom but with an undrilled area:

I have seen A LOT of pumps like this, too many for them to all be replaced.

What engine # did your pump come from?
Maybe a later 1955/early 1956 engine came with a new top and an old bottom?

The fuel pump I posted above is also from a very original engine.
Bus engine # 20-1251855 (December, 1955)
Here are more photos:
https://www.thesamba.com/vw/forum/album_search.php?search_keywords=late+1955+Bus+engine

Thu Dec 07, 2017 9:38 am

Hi Everett,
you made me thinking again about the late 55 fuel pump. I could have sworn that the top is correct, but I guess you're right after checking some pics.

But I guess we can conclude that all the 55 pumps had a different top compared to 56 and later?
...got to learn a lot with my 19 years :D

Thu Dec 07, 2017 9:56 am

As far as I know the top and bottom were changed at the same time.

I have definitely seen some "wavy top" pumps where I think the bottom was replaced, probably due to wear from the mounting bolts or warping where it mounts to the case.

Sat Dec 09, 2017 7:37 am

Here is the pump of our October '55 production car. Engine serial 1-1195854.

Mon Oct 03, 2022 10:50 am

Great info/thread.

I have a flat top 8mm pump for my 52 split that unfortunately has a cracked base. Can I use a later base with my 8mm flat top until I can find the proper base? Thanks!