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Just purchased an unused 40083 ACDelco fuel pump to replace my leaking old repro one.
They look absolutely identical.
So why is it that the old inlet and outlet fittings do not have the same thread pattern as the old one???
Neither the inlet elbow or outlet fitting will screw into the new pump I just received! I cleaned them both with a wire brush and cleaner so there is no debris causing them not to thread in.
Are they different thread patterns for these fittings that I am unaware of?
When I google for replacement fittings, the thread pattern isn’t an option at all, just the fitting itself, which would lead me to believe there is no options.
The last thing I want to do is apply too much force, in an attempt to thread them in, then strip the treads, wasting the new pump!
Can someone please shed some light on my issue here. She’s been out of commission for a few weeks while I found a pump and had it shipped up to me. And now, as summer is passing the midway point, I have to wait longer while I figure this hiccup out.
If my memory serves me correctly the threads on the pump should be 1/4” PIPE THREAD, looking at the picture kind of hard to see but the threads in the pump look fine thread to me may be just the pic?
pipe thread are tapered & look more coarse like in your old pump, ( spacing of the threads thread to thread is wider, Sorry layman terms:-) I would call where it was purchased & see if they can give you some insight or return for another?
please let us know how u make out, Im always willing to learn
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16-'17-'18-‘19-'20-'21-'22-'23-'24
I agree with Chalie, the pump on the right has coarser threads, the one on the left is fine thread. EhWard, you did the right thing by not trying to force things, and your eyes are not deceiving you. Unless someone in the past used a tap to re-cut the threads on the old, I'd have to say they make the new ones differently. And again I ask why? If you are going to manufacture a part, it costs no more to make it the right way to start with. .
If my memory serves me correctly the threads on the pump should be 1/4” PIPE THREAD, looking at the picture kind of hard to see but the threads in the pump look fine thread to me may be just the pic?
pipe thread are tapered & look more coarse like in your old pump, ( spacing of the threads thread to thread is wider, Sorry layman terms:-) I would call where it was purchased & see if they can give you some insight or return for another?
please let us know how u make out, Im always willing to learn
Chalie
I contacted the seller but this a brand new, still in box fuel pump. Not refurbished.
Can you post better focused pictures of the threads of both pumps and post pictures of the fittings you want to transfer to the new pump. Sumpthin jes ain't right.
Can you post better focused pictures of the threads of both pumps and post pictures of the fittings you want to transfer to the new pump. Sumpthin jes ain't right.
Sure thing
Should be obvious which pump is the new one due to the cleanliness of the housing.
From the closeup pics, they certainly appear to be exactly the same, as far as thread is concerned
What don’t think? I agree, something ain’t right here because they are the exact same pump and the new one I got was new and not refurbished.
I believe both pumps are correctly threaded 1/4 NPS (maybe NPT, but I'm betting on NPS). In any event, with these clear pictures the threads look identical.
There is thread damage visible on the older pump.
Also, the threads on your hex fitting, notably threads #2 and #3 look slightly distorted.
It might be informative to obtain a brand new 1/4 MNPT fitting and try screwing it into the new pump. I'm betting it will thread in perfectly. If it does, I would stop trying to use the old fittings and go buy two new ones.
I believe both pumps are correctly threaded 1/4 NPS (maybe NPT, but I'm betting on NPS). In any event, with these clear pictures the threads look identical.
There is thread damage visible on the older pump.
Also, the threads on your hex fitting, notably threads #2 and #3 look slightly distorted.
It might be informative to obtain a brand new 1/4 MNPT fitting and try screwing it into the new pump. I'm betting it will thread in perfectly. If it does, I would stop trying to use the old fittings and go buy two new ones.
You know, that was an excellent piece of advice and I’m embarrassed that I didn’t think of it myself!
I happened to have some spare 1/4” fittings in my tool cabinet. Tried them out and they threaded right in, first try!
I will be ordering 2 new fittings tonight and hopefully have her up and back on the road in no time.
Gotta love this Forum, at least you weren’t under the car with the pump bolted up & ran into this issue, nothing more frustrating, glad you figure it out….
Rebuild the old one as a standby. Also, can't tell from your photos, is there a embossed AC on top?
Before doing that, I'd spend some time with a NPS tap to see if the fittings' threads could be salvaged. If they can't be, there'd be no point in rebuilding.
Rebuild the old one as a standby. Also, can't tell from your photos, is there a embossed AC on top?
All I ever wanted to do was rebuild my old one. It’s easy as pie to rebuild a fuel pump. However, rebuilding the old one is not even a possibility.
I searched and searched the internet from
one side to the other, top to bottom and absolutely no where is there a rebuild kit available. They are completely discontinued, just like the genuine 40083 fuel pumps.
I even came on here asked the forum where I could find a rebuild kit for the 40083 fuel pump…no luck at all.
If anyone seeing thing knows where to find a rebuild kit, please forward that info my way. Then I can return this pump and get the stupid amount that I paid for it back!
You may be able to get a kit from Then and Now Automotive. Fellow (Tom) there told me they make them but are waiting on some parts they need for the kits. https://www.then-now-auto.com/Then And Now Automotive
447 Washington St
Weymouth,Ma 02188
781-335-8860 781-335-1925 Fax
I recently purchased some kits from them to rebuild 4656 pumps. Good service and communications!
Just purchased an unused 40083 ACDelco fuel pump to replace my leaking old repro one.
They look absolutely identical.
So why is it that the old inlet and outlet fittings do not have the same thread pattern as the old one???
Neither the inlet elbow or outlet fitting will screw into the new pump I just received! I cleaned them both with a wire brush and cleaner so there is no debris causing them not to thread in.
Are they different thread patterns for these fittings that I am unaware of?
When I google for replacement fittings, the thread pattern isn’t an option at all, just the fitting itself, which would lead me to believe there is no options.
The last thing I want to do is apply too much force, in an attempt to thread them in, then strip the treads, wasting the new pump!
Can someone please shed some light on my issue here. She’s been out of commission for a few weeks while I found a pump and had it shipped up to me. And now, as summer is passing the midway point, I have to wait longer while I figure this hiccup out.
I appreciate it in advance.
Cheers.
Sounds like you’re back on track. May I ask where you purchased the new one?
I sent my original AC pump out to Oregon to be rebuilt on April 4, 2023 and it took over 4 months to get it back. Put it on (1st time) and it leaked between the middle body and bottom cap. They changed the middle for some unknown reason and the casting slag on the bottom edge was so bad that the bottom cap wouldn’t seal. I flattened the high spots on the surface, put the bottom back on and reinstalled (2nd time) with no leaks. Started the car and within .5 second the AC logo on the top shot off. The diaphragm that hooks over the top of the lever must have had a clearance issue. Called the “so called” rebuilder and they said send it back and we’ll replace it. They sent me another, this time the top was warped at every one of the 10 screws probably from over tightening at some point. I hoped it wouldn’t be a problem and installed for the (3rd time). Car won’t start, no fuel is getting the carb. Took it off again. Figured I’d rig up a bench test so I connected 12” of rubber line with a funnel at the top, filled with fuel and started pumping the lever to see if I could pump fuel up the vertical hard line that goes to the filter. Lever moved easily with no resistance other than the return spring. Im now figuring all of the warping on the top section they provided is letting air in and the diaphragm isn’t sealing.
I’m ready to give up on the correct AC pump but all I can find are cheap $30 pumps with a return line fitting that I don’t need or know what to do with. Does anyone have any advice? I didn’t want to do this job once or have my car down for 5 months so any help to get this right one last time would be appreciated.
Warped top section on replacement pump First rebuild, diaphragm blew through top housing.
Sounds like you’re back on track. May I ask where you purchased the new one?
I sent my original AC pump out to Oregon to be rebuilt on April 4, 2023 and it took over 4 months to get it back. Put it on (1st time) and it leaked between the middle body and bottom cap. They changed the middle for some unknown reason and the casting slag on the bottom edge was so bad that the bottom cap wouldn’t seal. I flattened the high spots on the surface, put the bottom back on and reinstalled (2nd time) with no leaks. Started the car and within .5 second the AC logo on the top shot off. The diaphragm that hooks over the top of the lever must have had a clearance issue. Called the “so called” rebuilder and they said send it back and we’ll replace it. They sent me another, this time the top was warped at every one of the 10 screws probably from over tightening at some point. I hoped it wouldn’t be a problem and installed for the (3rd time). Car won’t start, no fuel is getting the carb. Took it off again. Figured I’d rig up a bench test so I connected 12” of rubber line with a funnel at the top, filled with fuel and started pumping the lever to see if I could pump fuel up the vertical hard line that goes to the filter. Lever moved easily with no resistance other than the return spring. Im now figuring all of the warping on the top section they provided is letting air in and the diaphragm isn’t sealing.
I’m ready to give up on the correct AC pump but all I can find are cheap $30 pumps with a return line fitting that I don’t need or know what to do with. Does anyone have any advice? I didn’t want to do this job once or have my car down for 5 months so any help to get this right one last time would be appreciated.
Warped top section on replacement pump First rebuild, diaphragm blew through top housing.
Bought if on eBay, new and unused, still in box. Really the only place I could find the proper replacement pump.
A couple sites, and I mean only 2 other sites anywhere, were both wanting $450 for a refurbished pump.
08-07-2023, 05:24 PM
Fuel Pump inlet/outlet Fittings
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