1957 return fuel line from fuel filter to tank; cars with Air Conditioning

[rich neary]

Posting this here to help with future searches.

I've read several inquiries regarding reason for second fuel line on some 1957's.
On 1957 cars w/ AC only there is a return line from the fuel filter (unique to A/C cars) that connects to the second (1/4") fuel line, going back to fuel tank. Here's an under hood photo of an original.

This is the first time I've attempted to add an attachment to a post here.
  Hope it works.
If not email and I'll send it to you
richneary@aol.com

Hope this helps,
Rich

[David King (kz78hy)]

That car is old, but the fuel line routing is not correct.  I will have to check to see if I have a non Brougham image which shows that routing.

Here is a 58 Fleetwood with a very close to correct routing.  Both rubber lines go down on the passenger side to the steel fuel lines on the frame.  The A/C fuel filter has the vapor line out the top of it.  The lines do not mount up and around the A/C compressor pipe.

Small details to work out.  Don't let this kind of stuff keep you away from a car, it is what can make it fun to get it right.  I am sure others will have a spot on image to reference.

David

[Gilbert Buras]

The attached picture is of the fuel sediment bowl and line routing on our “one-family” 16,000 original mile A/C equipped 1957 Series 62, just before I started rehabbing it after a 20 year dormancy.  I have no reason to think that this is not how it came from the factory. I personally replaced the fuel pump, filter and the flexible lines in the late ‘70s, when you could still get such things at the local auto parts store.

The line on the bottom of the filter housing does indeed return to the fuel tank. According to the shop manual it is supposed to be a vapor lock preventer, but how it is supposed to work being on the bottom of the sediment bowl beats me, and the shop manual is silent. The whole thing has always looked to me like it is installed upside-down, but there is no doubt in my mind that what you are looking at is “as delivered”.

I have read in this forum that the fuel filter for the AC cars is unique.  How so?  Did it have some unique plumbing to let the vapor at the top of the glass bowl vent to the return line?  If anyone has more information on the internal plumbing, it would be appreciated.

With moderate outdoor temperatures at present, I have plugged the return fuel line and disconnected the heat riser spring and the engine seems much happier for it.

Because the car is so low mileage and unmolested I made an extensive photo record of everything underhood before I began rehabbing.  If anyone wants pictures of specific things for restoration purposes, just let me know.

[59-in-pieces]

Gilbert

First where are you.

Looking at your photo, Is your car a dual quad or 4 barrel.
The reason I ask is that there have been many posts on 57's with gold quad air cleaners - no dispute - with or without AC.
However, it seems to be unresolved if the air cleaner with a 4 barrel on a non-AC car is black.
While a 4 barrel on an AC car has a gold air cleaner.

Any help here.

Have fun,
Steve B.

[Gilbert Buras]

Hi, Steve.

I am in New Orleans.  The car is a factory air conditioned Series 62 and has one Rochester 4GC carb.  The air cleaner body is black.  Much of the paint is worn off and the red "AC" stamping is now too smudged to read. What remains of the paint looks to have been semi-gloss.

Every time I open the hood I have a debate with myself as to whether I should repaint anything under it.

Gilbert

[fishnjim]

Pretty sure this is covered in the '57-58 authenticity manual(CLC).   So check there if you're not sure or talk to a judge.   

The AC GF-97 is the three port fuel bowl filter for A/C cars.   Center port is the return.   
The GF-48 (two port) is correct for the non-A/C cars both years.

 

[Daryl Chesterman]

Gilbert, you ask about the difference in fuel filters for A/C vs. non-A/C cars.  Here are pictures of the two filters, courtesy of Caddy Daddy.

non A/C:  https://www.caddydaddy.com/shop-parts/1957-1958-1959-1960-1961-1962-1963-1964-1965-1966-1967-cadillac-without-air-conditioning-a-c-glass-bowl-fuel-filter-reproduction.html

with A/C:  https://www.caddydaddy.com/shop-parts/1958-1959-1960-1961-1962-1963-1963-1964-1965-1966-1967-cadillac-with-air-conditioning-a-c-glass-bowl-fuel-filter-reproduction.html

You will note on the one with A/C that it does not list it as fitting a 1957, but it appears that your filter housing is the same as the one I have on a 1959.  Maybe someone else will weigh in on the particulars of the 1957 fuel filter for the A/C equipped car.  Either filter is readily available from most auto parts stores.

Daryl Chesterman

[David King (kz78hy)]

I took a photo of the 1960 Master Parts List page showing the years and usage of the fuel filter.  The Eldorado Brougham unit is not shown and it is different but not needed for this discussion. 

The site will not accept a photo, very odd.

46 through 60  P/N 854464  A/C (Type GF-48K)   All cars on 1941 thru 1956; exc. air cond. on 1957, 1958; single carb exc. air cond. on 1959, 1960

1957  P/N 854474  A/C (Type GF-51) air cond.
1958  (When exhausted use 854630)  P/N 854497  A/C (Type GF-55) air cond.
1959; 1960 P/N 854630  A/C (Type GF-64)  air cond. & 3 carbs.

David

[Gilbert Buras]

Thank you, gentlemen, for the part numbers.  It may be a "manufactured memory", but I do seem to recall the original filter having a closed top and the bowl not looking like a coffee percolator as it does now with that open top Wix filter I got from Rock Auto.   

BTW, I have looked all over the Club's website for the authenticity manual and not found it.  Will go look again.

[Daryl Chesterman]

Gilbert, here is a link to the Authenticity Manualâ€"order only, not the actual manual

     https://www.cadillaclasalleclub.org/store/ViewProduct.aspx?id=7782546

If you click on the "Technical" tab at the end of the black bar on the above web address, it will give you some more options for authenticity.

Daryl Chesterman