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Fuel filters specifically for 68 with a/c.?

Started by Steve W, March 20, 2023, 04:01:17 PM

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Steve W

Just talked to Cliff at Classic Tube. 68 and 69 are the same, 5/16 inch fuel line with a 1/2 inch wrench to tighten. So I ordered the line for the 68. I'll keep the filter I have now and maybe someone will be willing to give up one of the NOS 68 units they are hoarding, lol, and I will research switching everything over to 69 spec eventually.
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Steve W

Quote from: Cadman-iac on March 22, 2023, 06:31:45 PM... One nice thing about the paper filters is that they have a check valve on the inlet side that aids in preventing the fuel from draining back down the line if the car sits for a long time, making for easier/ faster starts.
  Rick

I will look into that too and get the right filter for my q-jet and make sure it has the check-valve! Thanks for that tip Rick!
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Cadman-iac

  Glad to help Steve.
  Another thing that you should look at if you're able to do it, is have a look at the well plugs on the bottom of the fuel bowl to see if they're leaking. You would have to remove the carburetor and take it apart to see that. There's actually 5 plugs there, 2 large ones that sit in the center of the throttle plates, and 3 up front in the area where your pcv is plumbed in. Of the 3, the 2 that match are your primary well plugs, and the other one is for the accelerator pump passage.
 Napa used to have a kit that you could install for the secondary plugs that had an O-ring on each new plug and a extended tip that would make contact with the throttle plate to keep it from coming out. I believe the part number was a 2-82 on that.
 For the front 3 plugs, the most common method that I've seen used is to cover them with epoxy.
But those and a fuel filter without the check valve are the two most common reasons for why the Q-jet leaks down over time.
If after you replace your filter and you still have a drained carb after about a week, I'd look at the well plugs.
HTH, Rick
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

Steve W

Quote from: Daryl Chesterman on March 20, 2023, 06:33:22 PMNAPA part # 3040 (WIX 33040) shows the inlet and outlet lines as 5/16" and the vapor return as 1/4".  If these sizes match up with your steel lines, there should be no interference with the hose clamps.

     https://pro.napaprolink.com/p/FIL3040?impressionRank=1

I am not familiar with the 1968 car, but there may also be a filter behind the carburetor inlet.  Be sure to use a flair nut wrench along with another wrench to remove the fuel line from the carburetor.  Assuming it is a Rochester, there may be a spring loaded filter behind the fuel inlet nut—be sure to note the orientation of the filter and spring.  Be extremely careful about cross-threading when reassembling as the threads are fine thread.

Daryl Chesterman


You are correct, there is also a "last line of defense" fine mesh screen in the inlet housing of the QJet. I took it out and cleaned it and re-installed it when I replaced my fuel line today.
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Steve W

Replacing the fuel line was a MAJOR PAIN!!! I saw a YouTube video where the guy replaced the solid fuel line on a 472 with a QJet , and it looked do-able. However I failed to take into account his deVille is a 71...guess what the 71 doesn't have? That dam a.I.r. Pump and the solid tube manifold that plugs into the heads. It's in the way of everything!

So the new steel line goes under the AC compressor, under the a.I.r. manifold tube, and on top of the alternator bracket. I almost removed the ac compressor but instead I removed the alternator bracket and belt, slacked off the power steering pump and removed the belts...then struggled with snaking the new steel line under and around the AC lines, and all the aforementioned hardware.

Then, of course, the ends don't quite meet. The steel line needed to be "not-so-gently persuaded" to meet up with both ends of the fuel filter and the fuel pump.

But...I did it... and without pinching the line anywhere... and it looks great! No more rubber tubing inserts with hose clamps torqued too much because the cut steel lines weren't flared (there was ANOTHER one on the line under the AC lines that I didn't notice until today) and no leaking anywhere! Peace of mind!

Now I just have to hope my OEM fuel filter lasts forever!
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

IcebearLars

Quote from: Steve W on March 21, 2023, 12:32:29 AMFound this on the web. I guess it's the WIX fuel filter for 68 Cadillac. Kida looks like the stock one! Its not made anymore either.s-l500.jpg

Last week I was lucky to get one of these for 65 bucks for my '68 Eldorado on ebay - will see how it fits

Steve W

Quote from: IcebearLars on April 06, 2023, 03:29:58 AMLast week I was lucky to get one of these for 65 bucks for my '68 Eldorado on ebay - will see how it fits

Great! Follow up when you see if it fits or not!
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Gene Beaird

I can confirm that the fuel line between the fuel pump and carb on a 1968 Calais is 5/16".  Looking around, I see a similar fuel filter for the Corvair Spyder that looks promising:

https://californiacorvairparts.com/fuel-system/1399-new-turbo-fuel-filter.html

The trouble is, all that's mentioned is the vapor line size, which is 1/4".  The hard line does look to be bigger, so perhaps it's 5/16"?  Maybe an email to the reseller noted above would provide an answer? 

Alternatively, you could probably go with a 1969 fuel pump setup as noted above, but you'd need to change the inlet on the carburetor to work with the 3/8" hard line.  The carburetor side of the inlet is a standard size, so getting one for, say a 1969 Corvette might work? 

There's still the question of the inlet to the 1969 fuel pump, though.  Being 3/8" flare outlet, I'd bet it's 3/8" also, requiring some adapting on that side.  With the amount of fuel flow you'll need on an old Cadillac, though, I bet a 3/8" to 5/16" hose reducer on that end will be fine:

https://www.ebay.com/itm/374599908825?hash=item5737e4fdd9:g:uq4AAOSwvV1kKDQE&amdata=enc%3AAQAHAAAA4LcR01AJXpD8Rom580NCDrm60JdC2TJvHFK0Pybyijpt0XyWfjTZHszpMH%2BObdB37ovlAkK2iAmPDgKnmmdbm2QhxagZya%2F%2FU2hvJWm5mDWQd1oIJAAyR%2Fsbn7IlCTsYWtJR2vK74gu0%2FtsDhRQSkzE0%2B%2BoDYaTsVKC3DEhDkud0g%2BMRM8G5RyDXAstodVdcYtiPFLaknPik5WHYG%2BTPiU7p67NlNbBD%2Bx%2F%2FKuEN14e8xLsuZuNJExzCBez5na%2FMrD4Jvo%2FTNikQ59jNHUbR0yFl7%2Fmg9u5auGiArBU8u2tR%7Ctkp%3ABFBM4szN-uph
Gene Beaird,
1968 Calais
1979 Seville
Pearland, Texas
CLC Member No. 29873

Steve W

Just as an example of what the wrong "shade-tree mechanic" can do, here is my fuel line that I pulled out of my car. The top is where it goes into the QJet, the bottom "L" piece into the fuel pump, and the longer rubber hose is the return line (factory).
What a mess, and all because the OEM fuel filter is impossible to find. The guy didn't even flare the ends of the steel lines that were cut! No wonder I was always chasing leaks!
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Cadman-iac

  Steve,

 Now that I know how to post pictures, this is a picture of what I had thought you were looking for when I first read your post. As you can see, it's just a little different.
 
  Rick
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

Gene Beaird

Quote from: Steve W on April 07, 2023, 10:38:03 PMJust as an example of what the wrong "shade-tree mechanic" can do, here is my fuel line that
I pulled out of my car. The top is where it goes into the QJet, the bottom "L" piece into
the fuel pump, and the longer rubber hose is the return line (factory).
What a mess, and all because the OEM fuel filter is impossible to find.
The guy didn't even flare the ends of the steel lines that were cut! No wonder I was always chasing leaks!


Wow, what a mess!  There's hardly an inch of the OEM line that's NOT been molested. 
Gene Beaird,
1968 Calais
1979 Seville
Pearland, Texas
CLC Member No. 29873

TJ Hopland

You kinda wonder why they didn't just do mostly hose with one of the more universal inline filters.  I suppose maybe they were concerned about the lack of a return and the OE filter wasn't that hard to find at the time?
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Cadman-iac

  Hey Steve,
  I was looking at the illustration catalog for another reason and I found this on the fuel system for the years of 68 to 73.
 I thought you might be interested, since it shows the differences between the 68 and the following years. The 68 was the only one that had an external filter, all subsequent years used an in-pump and in carb filter.
 
 Rick
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

Steve W

Quote from: Cadman-iac on April 11, 2023, 01:54:23 PMHey Steve,
  I was looking at the illustration catalog for another reason and I found this on the fuel system for the years of 68 to 73.
 I thought you might be interested, since it shows the differences between the 68 and the following years. The 68 was the only one that had an external filter, all subsequent years used an in-pump and in carb filter.
 
 Rick

Yep! That's it! Thanks Rick!
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

IcebearLars

I have requested the sizes of the fittings at californiacorvairparts for the bad boy @Gene Beaird found

Quote from: Gene Beaird on April 06, 2023, 01:45:08 PMI can confirm that the fuel line between the fuel pump and carb on a 1968 Calais is 5/16".  Looking around, I see a similar fuel filter for the Corvair Spyder that looks promising:

https://californiacorvairparts.com/fuel-system/1399-new-turbo-fuel-filter.html
...

TJ Hopland

Its interesting that that specific parts manual doesn't show a one piece 5/16 or 3/8 line for the later models.   Or that the 68 pump doesn't have the giant can on it.  You would think details like that would help the parts people figure things out.  That looks more like a diagram you would find today on ebay where it really doesn't help you figure out what you are trying to order.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Cadman-iac

#36
  Hey TJ,
  The parts system was a lot different then than it is now. The illustration catalog was only for reference purposes to assist the partsman in locating the appropriate group number in order to get the right part number. You seldom see any part numbers listed in the illustration catalog. When I started at the first dealership I was trying to remember the part numbers for the most often used parts, but found out quickly that GM loves to supercede numbers. I soon learned that the trick was to memorize the group numbers, because they never changed. Even up to the point when they began switching over to the computer cataloging, the illustration catalog was just for reference. The first few years after the computer cataloging began, you could still order paper catalogs, which was nice for the smaller dealerships that couldn't afford the computer system right away.
  Today people expect everything to be available on one screen, or they are prompted by the computer to get to what they're looking for. One reason why I hate going into places like Auto Zone.
  GM has a very good parts system in my opinion, just as Ford does. However Ford uses a grouping that's included in their part numbers. A good Ford partsman can look at a particular part number and be able to tell you what years it fits, and what models in most cases, as it was explained to me by a friend who worked for a Ford dealership.
 
  Now today's GM parts system is completely computerized, but it still helps to know what group number you want in order to quickly get your part number, but it's not required. You can type in the name of the part you want, and you'll get a list of parts and groups to choose from. Just typing in filter would get you a long list, and you will still need to choose the group, 1836, 3890, 4197, 3410, or any of a number of other groups. Once you have the group number, it's basically just a matter of narrowing down by description and option codes. Interior trim and upholstery are the worst to look up, especially if the option codes are not available.
  I used to have to go out and write down the option codes from a vehicle in order to locate the correct part. Now all the partsman needs is the Vin number and it all comes up on the screen and highlights each part that would fit that particular vehicle. It takes the guesswork out of most of the job. But years from now, nobody is going to have any parts catalogs to look at in their garage like we can do now.
 Before the computer was mandatory for the dealerships, you had a choice of what you wanted to order, paper catalogs, or microfiche. We tried the microfiche, but it sucked. The fiche would scratch, you couldn't switch between sections easily, and you still had to write down everything so you could type it into the inventory computer.
I hope that answers your question.

Rick
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"