40083 Fuel Pump Spring

[George J.]

All,
I just pulled the fuel pump on my '65 for the second time in 10 yrs. Both failures have been due to the lever arm spring that has broken. It seems to me that this spring should last much longer than this. I have seen others post that they, too, have had this spring break causing fuel pump failure. Has anyone researched a stronger, longer lasting spring for this application. My guess is that the current rebuild spring is some cheap piece of junk from China. After I put this pump in I don't want to do this job for a long time as it really is a pain in the you-know-what. Thanks.

George Jerome Jr
#31887

[George J.]

Re: 40083 Fuel Pump Spring

Bump

I assume that since no one replied, that there is no information, opinion, etc. on this? C'mon guys, I know someone has to have some comment on this.

George

[Gene M.]

Re: 40083 Fuel Pump Spring

use a spring from another used original passenger car pump I think they are all the same (excluding current china s%@#). go junk yard shopping.

[William C.]

Re: 40083 Fuel Pump Spring

Actually, the spring for the 40083 was unique to that application, where virtually al the 59-66 smallblocks used spring P/N 5621566, which is 15 coils, with a 1 3/4 free length, the 40083 used P/N 6413206, with a 10 coil configuration. My bet is that all the repro vendors did not check this and have the incorrect spring. Check the coil count on your broken one.

[Joe L.]

Re: 40083 Fuel Pump Spring

Actually, the spring for the 40083 was unique to that application, where virtually al the 59-66 smallblocks used spring P/N 5621566, which is 15 coils, with a 1 3/4 free length, the 40083 used P/N 6413206, with a 10 coil configuration. My bet is that all the repro vendors did not check this and have the incorrect spring. Check the coil count on your broken one.

Bill-----


Yes, and the 6413206 spring was uniquely applicable to the 6440083 pump; I can find no other applications. It was discontinued without supercession in November, 1973.

The 40083 fuel pump remains available from AC Delco. Does it still use the 6413206 spring? That I do not know.

[Dan H.]

Re: 40083 Fuel Pump Spring

Bill, Joe, I looked at 2 'Delco' replacement fuel pumps I have as spares, they both had 10 coil springs on the lever, also checked my Paragon rebuild kit, it too had approx 10 coils. Maybe it's not an incorrect spring issue, just a bad spring?
Dan

[Stuart F.]

Re: 40083 Fuel Pump Spring

George;

This may seem like a dumb question, but did you by any chance find a greasy like substance around the pump arm?

Reason I ask is that I once had a pump in an 80 Caprice that was breaking springs every couple of months and I could not understand why. I found a greasy substance in the pump, and also started to notice some on the bottom of the oil fill cap (know where I'm going with this?). Then one day one bank of rockers all started to make noise and I knew I had a serious problem. It had turned a cam bearing, and even my Mobil 1 could not prevent it. I was running half oil and half antifreeze in my crankcase. I checked it in with my dealer who hadn't the foggiest idea how this could happen, and then I got the news from some friends in Detroit that a whole bunch of late 79 mfg. 5 liter blocks had porosity cracks. Sure enough on tear down, we found the block cracked in the valley from front to back. Apparently, the antifreeze attacks the springs somehow causing them to break - weird, I know. They figured if it wasn't for the Mobile 1, it probably would have crapped out sooner. As it was, it went about 5000 miles after the first symptoms were noticed.

Stu Fox

[George J.]

Re: 40083 Fuel Pump Spring

Stu,
No, I did not notice anything when taking the old pump off. It has been at least 5 years since the pump was installed. My impression is that the spring is just a poorly made piece. I have done some research and found others posting on other boards of the same problem. I am wondering if it is some combination of a poor quality spring and a high performance (6000+ rpm) engine.

I am very reluctant to put in a 40 yr old used spring as some have suggested.

Joe, do you think that there is any chance in finding an NOS spring? And I don't want to hear that you have 10 that are not for sale.

I thank you all for the information, so far. As stated in a newer thread, this job is a pain. If anyone comes up with more info or a different idea, please post.

George

[Joe L.]

Re: 40083 Fuel Pump Spring

Stu,
No, I did not notice anything when taking the old pump off. It has been at least 5 years since the pump was installed. My impression is that the spring is just a poorly made piece. I have done some research and found others posting on other boards of the same problem. I am wondering if it is some combination of a poor quality spring and a high performance (6000+ rpm) engine.

I am very reluctant to put in a 40 yr old used spring as some have suggested.

Joe, do you think that there is any chance in finding an NOS spring? And I don't want to hear that you have 10 that are not for sale.

I thank you all for the information, so far. As stated in a newer thread, this job is a pain. If anyone comes up with more info or a different idea, please post.

George

George----


Given that this piece was discontinued almost 36 years ago, I think that finding an NOS example will be difficult. I do not have any, for sale or not for sale.

[George J.]

Re: 40083 Fuel Pump Spring

More information.

Joe,
thank you. It seems that I didn't look closely enough when removing the pump. When I removed it, and the spring fell out in pieces, I didn't look any further. Upon a closer inspection, I found that the pivot shaft is completely missing. I am wondering if the shaft broke, which then caused the spring to break. The pivot arm on the rebuilt original looks fairly stout.

It is interesting that the spring on this rebuilt pump is long enough (10 coils) to actually have a slight arc as installed and in its extended position. That does not seem to be the optimal way for a spring to function. On the other hand I am just a civil engineer and not a mechanical engineer. Anyone have any opinion?

Thanks in advance.

George

[Stuart F.]

Re: 40083 Fuel Pump Spring

George;

Most every pump spring I have seen on Chevies has been arced. The pump arm is at one angle and the pump cavity is at another. The locating stubs do not point at each other. They are probably more closely aligned when under compression.

Stu Fox

[Joe C.]

Re: 40083 Fuel Pump Spring

More information.

Joe,
thank you. It seems that I didn't look closely enough when removing the pump. When I removed it, and the spring fell out in pieces, I didn't look any further. Upon a closer inspection, I found that the pivot shaft is completely missing. I am wondering if the shaft broke, which then caused the spring to break. The pivot arm on the rebuilt original looks fairly stout.

It is interesting that the spring on this rebuilt pump is long enough (10 coils) to actually have a slight arc as installed and in its extended position. That does not seem to be the optimal way for a spring to function. On the other hand I am just a civil engineer and not a mechanical engineer. Anyone have any opinion?

Thanks in advance.

George

George,

Here are a few photos showing an original 40083 pump which I rebuilt last year. I re-used the original return spring , which appears to have ten coils. I also re used the original pivot pin (top-center of last photo, along with "special" retainer washer which I made-up), and both follower and link arms which also appear in the last photo.
I hope these help you. I don't remember any issues with the return spring. It went in place easily after the pin was re peened into place. I don't recall any significant bend in the spring either, when compressed, it looked straight, to me.

[Stuart F.]

Re: 40083 Fuel Pump Spring

You're right Joe. That spring looks pretty straight in that model. I gues my recollections are of different ones over the years. Just looked at a new 5325 I have in the garage and the spring is a smaller diameter, and long enough to have some noticeable arc to it.

Stu Fox

[George J.]

Re: 40083 Fuel Pump Spring

Joe,
Thank you. Yours looks much better than the one I have. I will try and post a picture.

Stu, thank you, also, for the information on the spring. Looking at Joe's picture, though, it looks like I would have thought GM would have designed it.

George