Airtex Fuel Pump Faults - Pivot Pin

[Richard M.]

Helping someone by phone to diagnose what we thought was a intermittent electrical issue on his 1966 327/350(cloned from a 300hp). Car would stall when hot. Squirted fuel when blipping throttle. No spark was observed during crank with coil wire close to ground.

Cool down later after flatbed tow home and it would restart. We found a leaky(oil) ignition coil- post, and a frayed coil- wire terminal. Changed coil with a new NAPA IC12 replacement, he fixed the coil- wire terminal, and we thought all was good. Several local drives for quite a few miles and all was okay. We thought we were all set. However I wasn't comfortable that it was fully solved for some reason. I wasn't there to verify if there was a fuel delivery issue or not.

When he touched the frayed coil- wire it broke off.


Oil leaking out of coil- stud area.


Then it happened again next time out, this past Saturday. Stalled out when hot away from his home. Cranked but no start. He waited 4 hours for the flatbed this time. Not a fun day.

Back at his home, I spent time on the phone with him the last few days trying to diagnose further. With ohm meter we checked distributor ground, breaker plate ground wire, points, Ign Switch voltage, ballast, etc. We did all checks with ohm meter while rotating the breaker plate. All good. Checked carb for fuel. Squirted when blipping throttle, but didn't seem like a large volume, and couldn't get multiple squirts. Maybe a fuel delivery issue now? He checked carb fuel filter. Good. New fuel tank and lines not long ago. We didn't do a fuel pump pressure test, yet.

Then I asked him to look at his fuel pump. This was his Airtex 40083 he replaced in 2011. He still had the box. Unsure how many miles on it. I asked him to send me a photo of his pump to see if was leaking. Looked wet to me, so we decided the pump is bad. I mentioned to him when he locates a new pump to be aware of the pivot pin issues on the new pumps. We looked online but photos not clear enough to decide which had the potential pivot pin problem or not.


I didn't notice the pivot pin at first on HIS pump. I was just looking for signs of leaking. Above picture was taken early this morning. Notice how far the pin is out, upper left view of pump to engine flange. I didn't notice this until he sent me the second photo.

This was taken a hour later. Engine was not run between photos. It seems like it walked out further, by itself. This must have been his fuel delivery problem. Maybe this was his problem all along, but he may have had a intermittent hot coil problem also.


So be aware of this Airtex Pivot Pin issue. You may want to check your fuel pumps next time your hood is open.

BTW, this is his AC 40083 he took off 11 years ago. Notice the pivot pin is a swedged rivet. I believe this is a original pump.


Rich

[Dave S.]

Re: Airtex Fuel Pump Faults - Pivot Pin

Rich,
Why not send his old A/C 40083 to Arthur Gould in Massachusetts. For about $100 plus shipping he will completely rebuild it with modern ethanol gaskets etc. It will look and function better than new.

[Richard M.]

Re: Airtex Fuel Pump Faults - Pivot Pin

Rich,
Why not send his old A/C 40083 to Arthur Gould in Massachusetts. For about $100 plus shipping he will completely rebuild it with modern ethanol gaskets etc. It will look and function better than new.

Dave, When I talked to him I mentioned about rebuilding it too. Definitely a better solution.

Rich

[Leif A.]

Re: Airtex Fuel Pump Faults - Pivot Pin

Rich,
Unfortunately, the Airtek fuel pump pins are infamous for "walking out". He might consider a Carter replacement pump. See below.

https://www.rockauto.com/en/moreinfo.php?pk=295919&cc=1322132&jsn=489

Or, fabbing up a piece of sheetmetal, as shown, to install with the Airtek pump with pin.

[Richard M.]

Re: Airtex Fuel Pump Faults - Pivot Pin

Rich,
Unfortunately, the Airtek fuel pump pins are infamous for "walking out". He might consider a Carter replacement pump. See below.

https://www.rockauto.com/en/moreinfo.php?pk=295919&cc=1322132&jsn=489

Or, fabbing up a piece of sheetmetal, as shown, to install with the Airtek pump with pin.

Leif, Thanks for the link.

I've seen that mod too. It's too bad this problem is so common.

Rich

[David L.]

Re: Airtex Fuel Pump Faults - Pivot Pin

Rick,

I agree with Dave S. Have the original AC 40083 pump rebuilt. There is no question in my mind that the pump is original as it has the "AC" casting, the "40083" stamped part number, and the very important gussets which are very visible.

Dave

[Don H.]

Re: Airtex Fuel Pump Faults - Pivot Pin

I have had this happen twice, not fun. Don H.

[Joe L.]

Re: Airtex Fuel Pump Faults - Pivot Pin

Rick,

I agree with Dave S. Have the original AC 40083 pump rebuilt. There is no question in my mind that the pump is original as it has the "AC" casting, the "40083" stamped part number, and the very important gussets which are very visible.

Dave

Dave-----


Yup. I agree, too. For the "screw type" (i.e rebuildable) pumps, rebuilding is the way to go. It's the best of both worlds---an original and correct appearing pump with modern internals ( since restoration is not a religion for me, using original internal parts is unimportant and definitely inadvisable). The thing I don't know, though, is whether current rebuild kits contain a pivot shaft which is any different than the "Airtex" shaft.

[Richard G.]

Re: Airtex Fuel Pump Faults - Pivot Pin

Great article, much appreciated.
It is interesting to me that much of the R&D work GM did for reliability didn't transfer to many of the modern sourced parts. We have become a country of the only thing that matters is cost. The manufactured saved .02 cents. What does a flatbed cost now? Sometimes it's a Crazy world.
Rick

[Richard M.]

Re: Airtex Fuel Pump Faults - Pivot Pin

Rick, So true. I read some reports over on corvetteforum that several folks talked to Airtex and they allegedly corrected the problem, but nothing other than more Loctite on the pin. As others stated there, once the pot metal gets worn, nothing will keep the pin installed.

After more searching and no comfort, my friend decided to send his original out to Arthur Gould for rebuild. He was told 2-3 day turnaround plus ship to/from time. Cost plus shipping apx $100.

Rich

[Joe L.]

Re: Airtex Fuel Pump Faults - Pivot Pin

Rick, So true. I read some reports over on corvetteforum that several folks talked to Airtex and they allegedly corrected the problem, but nothing other than more Loctite on the pin. As others stated there, once the pot metal gets worn, nothing will keep the pin installed.

After more searching and no comfort, my friend decided to send his original out to Arthur Gould for rebuild. He was told 2-3 day turnaround plus ship to/from time. Cost plus shipping apx $100.

Rich

Rich-----


I don't know the OD and length of the pivot pin offhand. However, I think the best solution for the pin retention problem is to use a clevis pin with external retaining ring groove and external retaining ring. These pins are usually case hardened and are even available in stainless steel. McMaster-Carr has a wide selection of sizes available.

If the pin bores in the pump casting are worn or enlarged and one wishes to use the casting, I think the casting could be machined out and bushings installed. Using oilite bronze bushings might make the casting "immortal".

[Richard M.]

Re: Airtex Fuel Pump Faults - Pivot Pin

Good idea Joe. I think that's exactly what Airtex should have done!

There must be hundreds of their pumps out there failing.

Rich