68 SDV various stuff

[Kell Oskarsson]

All,

I´m a newcomer here. Recently bought a ´68 SDV and am really just getting started. If anyone could help me out with the following small points I´d be really grateful:

- Fuel filter: I haven´t so far been able to locate a replacement fuel filter at any online shop. The workshop manual says the filter is located in front of the engine near the fuel pump and has some kind of vapor outlet that connects to the fuel tank. Question: Can I get the correct filter anywhere or has this been replaced by a more conventional in most cars? Also the manual indicates that you have to get the car on a hoist and replace the filter from underneath (dread!) Must confess that I haven´t gotten under the car yet to have a look but since it´s a low mileage mostly original car I suspect it has the factory setup.

- Interior lights: I need to replace the bulbs in the rear interior lights (the ones in the C-pillar) but cannot get the lens/bezel off. Cannot find anything in manual on this. Do I twist the bezel to get access to the bulb?

- THM400: There is a leak from the trans somewhere so anticipate having to obtain a gasket set. Question: Are all years/models of THM400 the same (apart from the lenght of the extension housing) and can you recommend a source for a good quality strainer/gasket/oil seal set?

Best regards,

Hrafnkell (Kell) Oskarsson.

[35-709]

You say workshop manual?  If you have the '68 Cadillac Shop Manual (and you should have), you will see that the fuel filter is in the fuel pump itself (there is an illustration and complete instructions in the manual), you must remove the pump to carb fuel line at the pump and then take the large nut off to access the filter.  Use 2 wrenches, one to loosen the fuel line nut while you hold the larger nut, then remove the larger nut.  If this has not been done for awhile be very careful that the fuel line nut is not rusted to the line itself which will twist the line.  A squirt with something like PB Blaster first (let it soak in for a while) will help prevent ruining the fuel line.  Replacement lines are available from Inline Tube (http://inlinetube.com/).  Clamp off the rubber line coming to the pump from the fuel tank to lessen the gas that will flow out of the pump when you loosen the gas line.

You could jack the left front of the car up and support the car with a jackstand and do it on the floor but be prepared to get gas up you sleeve, in your face, etc., don't forget to clamp that rubber line.  Hmmm, I see you are in Iceland, that makes parts hunting more difficult.    Don't know for sure about those interior lights.
Geoff N.

Speaking of rubber fuel lines, check the condition of ALL the rubber fuel lines, at the pump and at the tank, harder to get at by the tank but they DO go bad with age and will leak!  If they haven't been changed on your car they most certainly are ready!

[TJ Hopland]

I dont have a 68 or a shop manual for a 68 but in the early 70's the fuel filter was located in the fuel pump.  The pump looks like most GM pumps of the era except the canister part (that points down) was much longer.  There were two lines attached to the canister, the 3/8 line is the supply to the tank and the 1/4" is the return to the tank.   There is then a fairly large nut that then has the steel line that goes up to the carb.  To replace the filter you have to unscrew and move the steel line out of the way. (Good luck with this step if the car has ever got wet and has not been apart in the last 40 years).  You then unscrew the big nut and the filter drops out.  The filter looks just like the ones that fit direct in the carbs in later years.  The gasket for that nut is one of those parts that they never seem to have made and has never existed.    On one of my cars I had to use a tubing cutter to cut the tube because it would not turn.  I then use a piece of marine fuel line (very thick wall) to replace the bend in the tubing I had to remove.   If it had been a brake like I would have heated it with a torch to try and break it loose but being the fuel pump I did not think that would be a good idea.

Here is a shot from underneath.  This is a 75 Eldo so the frame is a bit different than yours would be and the pump does not have the filter and nut on it but the location and shape of the pump is the same.  The fuel pump is in the upper left of the photo.  The pump is located on the front left side of the engine sort of behind the power steering pump.
 

[Kevin M. Parkinson]

- Interior lights:

To gain access to the interior light bulbs in the C pillar you do not need to twist anything.  The opaque / white lens with the Cadillac symbol comes out of the light assembly and the chrome / silver part stays in place.  There are either two or three clips molded into the edge of the lens that holds it in the fixture.  Look carefully around the edge of the lens to locate these "clips".  You can use your smallest screwdriver to push the clip in (toward the center of the lens) and release the lens.  Be very careful because these 42 year old lenses crack easily if you force it out with too much pressure.

Kevin

[Glen]

On the ’68 the fuel filter is not inside the pump.  It is attached to the top of the pump.  See the attached parts manual picture.  It shows the ’69 and later and the internal filter is labeled as “except 1968”.  The external filter is labeled as (1968). 

The Delco part number is GF 440.  If you Google that number you will see it is getting hard to find. 

On my next fuel filter change I will install an inline filter in the hose below the pump and use the original filter as a tee for the return line. 

Glen

[Steve W]

The filters pop up on ebay from time to time. But they list them as filters for cars WITH a/c and filters for cars WITHOUT a/c. Don't know why a/c would make a difference. And yes, for the 68 they are separate from the fuel pump. On my car its just like the pic Glen provided.
I've never had to take my interior lights apart yet, so I don't know about that....yet....

Good luck with your car!

[Kell Oskarsson]

All,

thank you very much for your kind help. According to the manual, the filter for a/c equipped cars has a vapor tube connection going back to the fuel tack whereas the non-a/c does not. This probably explains the different parts numbers. Given the scarcity of parts I´ll probably switch to an inline fuel filter eventually.

I´m taking her out of storage by the end of next week so there will probably be a ton of stuff to tend to. This is originally a Georgia car that had been in storage for 10 years before the previous owner bought it and had it shipped to Iceland. Even after that it has only been driven intermittently. The car is very straight w/no rust to speak of and only has some 66k miles on it.

Best regards,

Kell.

[TJ Hopland]

Wouldnt that be a return line rater than a vapor line?   Other than the return line the picture of that filter looks a lot like the 80's and 90's filters used on the EFI systems.

[35-709]

Glen,
Thank you for that clarification about the difference in the '68 only pump/filter setup and Kell, my apologies for not having that correct.  I now remember having seen a discussion here before about the differences in the '68s but had no recollection of it until Glen pointed out --- again.
Geoff N.

By the way, would it not work to use a '69 or later pump on the '68 which would then give you the later and easier to find filter?  Would a change in the fuel line be necessary? 

[Kell Oskarsson]

Geoff,

replacing the pump with a more recent model sounds like a good idea. Do you happen to know whether a pump from a 1973 Eldo (500 CID) would fit? (A friend has a spare one that he´s willing to give me).

[35-709]

All I can say is it looks to me like it would, BUT, check the fuel line size, it may be different and you would have to work around that.
Geoff N.

[Kell Oskarsson]

I´ll have a look and see whether it works. Thanks!!!

Best,

Kell.

[TJ Hopland]

The 73 should have the internal filter.   The inlet is a 3/8.  Return is 1/4.   The outlet is 3/8.   Since the 68 filter is in the line and the return looks to be in the filter it would take some plumbing.  I would imagine the return line has to be rubber between the filter and frame mounted steel line so that one should not be a big deal.  I would think you could get a steel line from a 69-74 if you did not want to splice or put in a chunk of hose to bypass the filter.   75 went to the carb filter so I would think the steel line could be slightly different.

[Steve W]

FYI,
I contacted the guy on eBay and asked if he still had the fuel filters for the 68. Here is his response:

"Hi we have both the gas filters. w/AC is GF20 the one with no A/C is GF19. how many do you need?"

[Glen]

I can’t tell you what the differences are but the 69 â€" 72 pumps have a different part number from the 73 â€" 74 and maybe later.  My parts book is a 74 so it does not show later parts. 

You would need to use the 69 â€" 72 fuel line going to the carb.  The 68 fuel line is in two parts with the filter in-between. 

See list below. 

Glen

[Glen]

FYI,
I contacted the guy on eBay and asked if he still had the fuel filters for the 68. Here is his response:

"Hi we have both the gas filters. w/AC is GF20 the one with no A/C is GF19. how many do you need?"

Not according the parts book.  See below

Glen

[Kell Oskarsson]

Kevin - many thanks for the advice, I got the interior lights apart w/o problems.

Steve - could you please send me the name of the eBay seller who is offering fuel filters?

Many thanks!

Kell.