Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

[Darwin K.]

Hi all,

My mechanical fuel pump suddenly began spewing gasoline today. Luckily it was while I was working on the car at home.
I need ideas on how to get to the fuel pump on this car with factory air.
Do I approach everything from below?
How do I keep the push rod in the proper position?
I could find very little on our site and on line.
Any ideas on the best approaches will be greatly appreciated.
Thanks,
D. Kuhlmann

[Joe L.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

Hi all,

My mechanical fuel pump suddenly began spewing gasoline today. Luckily it was while I was working on the car at home.
I need ideas on how to get to the fuel pump on this car with factory air.
Do I approach everything from below?
How do I keep the push rod in the proper position?
I could find very little on our site and on line.
Any ideas on the best approaches will be greatly appreciated.
Thanks,
D. Kuhlmann

Darwin-------


For your application it's a bitch. In fact, even on a big block without A/C it's not really easy. You'll have to do just about all of it from below.

There is no way to easily hold the fuel pump push rod in the retracted position (i.e. there's not an easy way like there is with a small block). What you need to do is to first make sure that the pushrod is in its most retracted position (i.e. cam lobe on base circle). You can remove the pipe plug near the bottom of the fuel pump pad and, using a thin tool, push the pushrod up as far as it will go. While holding it in position, you have to install the fuel pump by sort of "angling it in". Once you feel the pump's rocker arm engage on the pushrod, remove the tool. It's a real juggling act and "trial and error" proposition.

[Frank D.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

I have heard of people using a dull hack saw blade as the thin 'push' tool....

[John H.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

It's also easier if you remove the right front wheel and go more or less straight in from the side.

[Joe L.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

Darwin------

Also, one more thing to keep in mind: make sure that you install the gasket before you start the installation of the pump. It's VERY easy to forget to do this in the midst of all the "intrigue" of installing the pump. But, if you forget it, you'll get to remove the pump and start all over again----not something you want to do after finally getting the pump installed. You can affix the gasket to a CLEAN mounting pad surface using a bit of 3M Super Weatherstrip Cement or Edelbrock "Gasacinch".

[Darwin K.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

Thanks everyone.

It looks like a very difficult task, especially with not having a lift.
Would it make any sense to remove the AC compressor and brackets ( the AC is currently nonfunctional because of STV leak ) ?
The fuel pump body has screws fixating it. Could I replace the diaphragm by taking the bottom off and rebuild while on the car?

All your help is most appreciated!
Darwin

[Darwin K.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

Thanks everyone.

It looks like a very difficult task, especially with not having a lift.
Would it make any sense to remove the AC compressor and brackets ( the AC is currently nonfunctional because of STV leak ) ?
The fuel pump body has screws fixating it. Could I replace the diaphragm by taking the bottom off and rebuild while on the car?

All your help is most appreciated!
Darwin

[Joe L.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

Thanks everyone.

It looks like a very difficult task, especially with not having a lift.
Would it make any sense to remove the AC compressor and brackets ( the AC is currently nonfunctional because of STV leak ) ?
The fuel pump body has screws fixating it. Could I replace the diaphragm by taking the bottom off and rebuild while on the car?

All your help is most appreciated!
Darwin

Darwin------


If you're talking about a "screw type" pump (i.e. with a ring of several screws retaining the bottom section of the pump to the top section), be advised that such a pump was never originally used for any Corvette big block or, for that matter, any other Mark IV big block that I am aware of. If yours is such a pump, I would have no idea what internal parts you would need to rebuild it.

Could you rebuild it on the car? Possibly, but it might be even more trouble to do this than removing the pump.

[Darwin K.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

Thanks Joe.
I guess I knew the fuel pump was not correct.
I was hoping to possibly just replace the diaphragm which I am sure is what failed, and hopefully save myself a lot of work trying to replace the whole pump.
Do you think I could get better access by removing the AC compressor/
Thanks again for the help.

Darwin

[Joe L.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

Thanks Joe.
I guess I knew the fuel pump was not correct.
I was hoping to possibly just replace the diaphragm which I am sure is what failed, and hopefully save myself a lot of work trying to replace the whole pump.
Do you think I could get better access by removing the AC compressor/
Thanks again for the help.

Darwin

Darwin-------

I think that most of what you will need to do will be done from underneath the car or from the side (with the right front wheel removed as John mentioned). So, I don't know that removing the compressor will help. However, it might help if you are just going to remove the screws to rebuild the pump in-place. Since the A/C system is not functional, removing the compressor should be no big deal.

The fuel pump must be aftermarket. So, in order to obtain replacement diaphragm and/or other parts you need, you'll have to identify it. I do not know that replacement parts for AC screw type pumps will be interchangeable.

[Darwin K.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

Again many thanks Joe,

The fuel pump is a Carter. I can't seem to find a good model number on it.

It looks like I can remove the fuel pump from below.
The question is can I put a new one in???
Some questions please:
!. the bolt in the block below the fuel pump mounting surface, does that keep the push rod in place? What do I need to know about that?
2. How can I keep the push rod in place with very limited access or do I need to worry about that?
3. What recommendations for a new fuel pump, I don't really want to pay big money for a correct one, a good service replacement will do me fine.
4. Do I need any gasket sealer or mounting bolt sealer/

I really appreciate the help!

DK

[Mark E.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

Don't be intimidated. I've done this job on big-block AC cars several times in my life with little drama. And if I can do it, so can you.

There's enough access from underneath the car (I typically use floor stands). The service manual specifies how to clock the engine so the push rod eccentric is not engaged. And make sure you're ready to plug the fuel lines as soon as they're disconnected or you'll be lying (laying? I never could remember how to conjugate that verb) in the middle of a large puddle of flammable gasoline (remember to wear safety glasses). During installation, try smearing axle grease on the push rod to hold it up and out of the way. And as Joe said, don't forget the pump gasket.

This is also a good opportunity to replace the rubber fuel hoses and their clamps.

These tips should make the job straight forward.

[Darwin K.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

Great advice.
Thanks for the encouragement Mark!!
I am now looking for a replacement pump, any suggestions for a service replacement that doesn't need to be NCRS correct.

DK

[Robert K.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

I will second Mark E. suggestion on how to keep the push rod in place. I have used this same technique (grease on the push rod) many times and it always keeps the push rod in place without having to worry about it "falling down" while the pump is put on the engine and bolts inserted.

Bob

[Joe L.]

Re: Need ideas on how to R&R a mechanical fuel pump on a 1966 427/390 AC car

Again many thanks Joe,

The fuel pump is a Carter. I can't seem to find a good model number on it.

It looks like I can remove the fuel pump from below.
The question is can I put a new one in???
Some questions please:
!. the bolt in the block below the fuel pump mounting surface, does that keep the push rod in place? What do I need to know about that?
2. How can I keep the push rod in place with very limited access or do I need to worry about that?
3. What recommendations for a new fuel pump, I don't really want to pay big money for a correct one, a good service replacement will do me fine.
4. Do I need any gasket sealer or mounting bolt sealer/

I really appreciate the help!

DK

Darwin------

I don't know if you can obtain rebuild parts for the Carter fuel pump. However, if they're available you'd probably need to identify the pump model number. You could check with Federal-Mogul Technical Service (Carter is a brand of Federal-Mogul).

As far as your questions:

The "bolt" below the fuel pump mounting pad is actually a pipe plug. It is through this orifice that you can use a slim tool to hold the fuel pump pushrod in place. It's also the orifice through which the fuel pump pushrod is removed. As others have suggested, you can remove the pushrod and coat it with grease. Then, re-install and the grease should hold the pushrod in place;

You can replace the pump with a GM #6416741 or a Carter M4552. These are both crimped-type pumps as was originally used on your car. These vary a bit in configuration from the original but they are more-or-less similar to the original. You can buy these pumps for about 30 bucks, or less.

Use 3M weatherstrip adhesive to retain the gasket to the block before installation of the pump. You could also use RTV but I think the 3M weatherstrip cement will do a better job of holding the gasket in place and it will do an adequate job of sealing. A thin film of RTV on the mounting bolts before installation can't hurt anything and might help.