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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

I really want to change my fuel filter, the one that's between the fuel pump and the carb, with the return line. I can't find the OEMs anywhere. I think they were 'one year only'. I tried the WIX, but can't get the two 5/16" lines on the outlets (too close together). I read here in the distant past, that someone recommended a mid-80's Chrysler fuel filter...It has the return line going out the side, so the fuel lines won't get in the way of each other, but there wasn't any follow-up. Has anyone done this...or any other creative fixes? My fuel lines have all been "adapted" by the previous owner's mechanic...meaning the ends snipped off and rubber lines with mini screw-clamps holding them on the filter.
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Daryl Chesterman

#1
NAPA 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


Cadman-iac

#2
Steve,
Not sure about the inline filter that you mentioned being original, but there is one just behind the inlet fitting on your carburetor, as Daryl mentioned. Use a 1 inch wrench to keep the large inlet fitting from turning as you loosen the fuel line.
 And also one inside the canister of your fuel pump if it's still the original pump.
There's a big nut on the bottom of the pump that the fuel line screws into.
I'm not sure if this filter is even available any longer though. Maybe someone else here knows that information.
HTH,  Rick
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

Steve W

Yes, I have the scintered bronze screen/filter in the fuel inlet of the Quadrajet. That's the last line of defense. Mine's clean, so I guess it means my primary fuel filter is doing its job! But 1968 is a weird year, especially if the car has a/c!! The fuel filter is free standing, not in the fuel pump. And it's held in place by the steel fuel lines (in my case, a combination of steel and rubber lines) it has one inlet, two outlets...one to the carb and one that returns to the tank (to help eliminate vapor lock). So the WIX doesn't work for the previously stated reasons, but I did see the Chrysler one...and it has the return line poking out of the side of the filter canister. So I was wondering if anyone has used one,
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Cadman-iac

  I have used one for my El Camino when I was trying to eliminate a vapor lock situation, but the issue turned out to be the electric fuel pump loosing pressure when it got hot.
 The filter works fine for this, and it's easy to install with hose and clamps.
 Just curious, what does your inline filter look like? Does it have the glass bowl that houses the filter?

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

Cadman-iac

#5
  Here's what I think you have, if I can get this picture to post.

 Well, that didn't work.

   Anyway, if it's what I think, it takes a GF149 filter, which is the delco number. The GM number is an 854567.

 I've got to learn how to post pictures on here again. This sucks!

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

Steve W

Found 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
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Steve W

This is the WIX Filter I bought, but I can't get both rubber fuel lines and clamps on the outlets, They're too close together.
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Steve W

And this is the one for Chrysler that I was talking about. No problem fitting the lines on this! I just don't know if it would work on Cadillac. (If the internals are the same, if it flows the same, etc,)
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Steve W

Bear with me...here's another thought. Would THIS filter work? Same inlet and outlet fittings? It's in stock from Classic Industries for 60.00. It says its for 69-74 GM (Chevy, mostly). But then I could order a new two-piece fuel line, made for the 68 deVille, 25.00 from Classic Tube that goes from the fuel pump to the filter, and from the filter to the carb. just like the factory setup...all steel tubing with no funky rubber and hose clamp "adapters". Thoughts?
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Cadman-iac

  Steve 
  Your last suggestion to go with the Chevrolet filter and new tubing would be ideal, as it would eliminate the rubber hose altogether, providing the filter has the correct size fittings for the tubing available. No chance of a rupture due to heat and deterioration and subsequent fire if not caught in time.

  I didn't know that the 68 used that design of inline filter originally. I was still thinking of the older cast aluminum housing with a glass bowl underneath it that housed a replaceable paper or sintered bronze filter used on the 429 engines. That's what I have that I was trying to post a picture of.
 I've had several 69's, a 70,  2 72's, a 75, 2 77's, and a 79, and none of those had an inline filter, just the carburetor inlet filter, and the early ones had the one in the pump as well.
 
  If you can verify the size for the line on that Chevrolet filter and it matches what you can get for a replacement fuel line, I would think that's the best way to go.
 Your other option is to remove the existing line and shorten it the required distance and reform new flared ends to mate with the new filter. I'm guessing that the flares are no longer on your existing line to accommodate the hoses?
 The other option would be to use a flaring tool to make a small bulbed end on your current tubing by not going through with a complete flaring process, you just begin the flare procedure slightly. That way it creates a little bump in the tube that will help keep the hose from just sliding off it under pressure. You don't have to crank the hose clamps down so far that it's crushing the hose to prevent it from sliding off that way.
 I've done this for my own vehicles if I'm installing an inline filter with hoses instead of flared fittings.
 Hope this is helpful, and good luck with your project.


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

Steve W

Doing further research...the GF 432 is all over the place, readily available. From 16.00-60.00. They seem to fit Pontiac GTO, Chevelle, Corvette, Camaro, etc. So why WOULDN'T it work for the 68 Cadillac? Would the threads be different?
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Cadman-iac

Quote from: Steve W on March 21, 2023, 08:18:15 PMDoing further research...the GF 432 is all over the place, readily available. From 16.00-60.00. They seem to fit Pontiac GTO, Chevelle, Corvette, Camaro, etc. So why WOULDN'T it work for the 68 Cadillac? Would the threads be different?

Some of those bigger engines used a 3/8" tubing instead of the 5/16" that Cadillac decided to use on the last great engine it built before switching to the 3/8" in the mid 70's I think it was.

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

Steve W

Quote from: Cadman-iac on March 21, 2023, 09:24:17 PMSome of those bigger engines used a 3/8" tubing instead of the 5/16" that Cadillac decided to use on the last great engine it built before switching to the 3/8" in the mid 70's I think it was.

  Rick

Well, shoot! Then that brings me to the next logical course...getting a 69 fuel pump (it has the return line built in), and having the one piece steel line made for a 69 and putting that on my car.
Does that pump have the filter built in? And if so, how do you change the filter?
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

"Cadillac Kid" Greg Surfas 15364

If I am not mistaken the fuel filter (up to 74 or 75 was in the fuel pump itself behind the big nut that the line to the carburetor comes out.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Steve W

Quote from: "Cadillac Kid" Greg Surfas 15364 on March 21, 2023, 10:37:21 PMIf I am not mistaken the fuel filter (up to 74 or 75 was in the fuel pump itself behind the big nut that the line to the carburetor comes out.
Greg Surfas

So, would that be like the small mesh or scintered bronze filter thats in the Quadrajet inlet?
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

TJ Hopland

The one that was used in the pump is a pleated paper filter.  It was also used on the inlet of some versions of the Qjets.  There is a long and short version of that filter, one is only like an inch tall and will fit in many of the q jets.  The taller version that fits the pumps is maybe 3".  You can easily tell the carbs that use this one because the inlet fitting housing thing is about 2" long, it really sticks out of the carb usually out the front IIRC. 

It looks like at least through 'regular' auto parts stores there is now only one fuel pump that they claim is correct for all 68-81 Cad motors and its got the 3/8 flare outlet with the filter, 3/8 inlet, and 1/4 return. We all know that earlier there were variations like no filter and 5/16 lines and I believe the 425's originally had a slightly smaller 'can' and slightly different orientation of the ports but 'they' have decided the 71-76 is close enough to say it fits all.  It also doesn't seem to matter what name is on the box, they all look identical at least the 3 different brands I ordered from 3 different stores a couple years ago were all the same.


Is the goal here to just get something that works?  What size does the carb have?  Is it also 5/16 or was that 3/8?  Then the original filter has 5/16 flare on both ends then the 1/4 nipple?  And its in the vertical section of hard line coming up from the pump?        
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

Steve W

Quote from: TJ Hopland on March 22, 2023, 11:20:15 AMThe one that was used in the pump is a pleated paper filter.  It was also used on the inlet of some versions of the Qjets.  There is a long and short version of that filter, one is only like an inch tall and will fit in many of the q jets.  The taller version that fits the pumps is maybe 3".  You can easily tell the carbs that use this one because the inlet fitting housing thing is about 2" long, it really sticks out of the carb usually out the front IIRC.

It looks like at least through 'regular' auto parts stores there is now only one fuel pump that they claim is correct for all 68-81 Cad motors and its got the 3/8 flare outlet with the filter, 3/8 inlet, and 1/4 return. We all know that earlier there were variations like no filter and 5/16 lines and I believe the 425's originally had a slightly smaller 'can' and slightly different orientation of the ports but 'they' have decided the 71-76 is close enough to say it fits all.  It also doesn't seem to matter what name is on the box, they all look identical at least the 3 different brands I ordered from 3 different stores a couple years ago were all the same.


Is the goal here to just get something that works?  What size does the carb have?  Is it also 5/16 or was that 3/8?  Then the original filter has 5/16 flare on both ends then the 1/4 nipple?  And its in the vertical section of hard line coming up from the pump?       

All good points TJ! I just want something that is going to work properly AND safely! To minimize any potential leaks developing over time. And, to NOT have the same issue down the road when 'they' stop making the parts, or some of these places go out of business. (It just seems odd that they still make the fuel pump for the 68, but not the filter.)

In 1968, the steel line was in two pieces...one piece from the fuel pump into the filter, the other piece out of the fuel filter and into the carb. All steel and all with fittings. It was very stiff and held the filter in place without needing a bracket of any kind. And the ONLY rubber hoses were the inlet of the fuel pump and the outlet of the 1/4" return line from the filter (to help eliminate vaporlock). And those are only a foot long or so and go to their respective steel lines that go back to the tank. The reason for the rubber lines in that location is to allow for a bit of engine vibration without weakening the steel lines.

The 69-74 fuel pump has the reurn line built in, and, apparently, some sort of filter inside, so it's  a solid steel line all the way from the pump to the carb.

Looks a LOT safer than what I have now...and the pumps are plentiful, as they are used in a number of differet applications. And the filters seem to be plentiful as well.

For my current set up, should my existing original filter clog or fail, I'll have to go back to what the previous owner's 'mechanic' did...just find a filter with a return and slap it together with all these extra rubber hose links...that will eventually leak.

My only question now is the end of the 69 line...will it fit into the Q jet? (I'm assuming the fuel pump end will fit). IMG_6458.JPGIMG_6459.JPGIMG_6458.JPGIMG_6459.JPG   
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Cadman-iac

#18
Hi Steve,
The 69 fuel line is originally a 5/16" tubing, so if that's what your car has now, it'll fit no problem.
I think it should be 5/16", otherwise the 69 through about 73 or 74, (not sure exactly when it increased to 3/8"), would have also been made with the 3/8" line.
Also, the Wix/Napa fuel filter for the Q-jet in 68 would be the short #3051. The longer version is the #3052.
The sintered bronze filter was only made in the short version, and I'm not sure you can even get one anymore.
As TJ said, you can tell which one your carburetor has by how long the inlet fitting is. The short one has a fitting that sticks out about 1/2" total, whereas the longer one sticks out about 1 1/2".
  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
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

TJ Hopland

How much room is there below the fuel pump?  The later pumps with the filter are a few inches longer than the more classic design plus the nipples and main outlet point straight down so you need a few more inches of clearance below especially on the hard line because it has to make a J bend.  Maybe there was a reason they didn't go to the in pump filter design till later?  Some part of a mount or the frame in the way?  With a C car and the front sump pan I would think there would not be anything there but I have never spent that much time under a 68.

If you got the clearance below the pump then the only question is is the carb inlet 5/16 or 3/8.  I know for smaller like brake size lines they make nuts to go one size up in the nut from the line so it may have been possible to have a 3/8 inlet on the carb with a 5/16 line.  If its 5/16 then does someone like inline tube make a 5/16 solid line for use with the bigger pump?  If so there was another thread where someone found someone selling a low profile 3/8 to 5/16 adapter to make the 3/8 pump work on a 5/16 car.
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