73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Fuel Systems and Drivability => Topic started by: philo_beddoe on June 16, 2018, 06:10:18 AM
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Ever seen this? What caused it? It may have been like this for a while, i'm not experiencing any problems. Used JB weld for a quick fix, will replace asap.
(https://uploads.tapatalk-cdn.com/20180616/222f95103226acefe70387137396ae4c.heic)
(https://uploads.tapatalk-cdn.com/20180616/c245f21bfe3a55f8603e086fe1b9ca9f.heic)
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Hard to tell from the pic but it looks like it's mushroomed on the corner. Did someone pry on it or hit it? It looks like external damage. Nevertheless, replace it.
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The dreaded fuel pump borer...…….
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Hi Philo:
From your photo it appears that something broke from the inside to the outside. What should be right below the place where the casting broke out is the diaphragm shaft of the pulse diaphragm...so either the top end of the shaft pushed through the casting or something came apart and then got stuck on top of the main shaft which then proceeded to squash it (and then through the cast wall) on the upstroke. Since your pump still works, it is most likely not the shaft that went through the wall but something that came between the top of the shaft and the wall. Although I am not very familiar with the inner workings of the standard Chevy 350 pump, I do know there is one or two springs on the drive lever...maybe one of these springs broke and a piece got stuck on top of the diaphragm shaft. I believe the pump can still work when one of these springs breaks. What would be interesting is that while you are replacing your pump is if you remove the JB Weld and take a look down the hole with a flashlight while the engine is idling and see if you see the end of the shaft moving up and down.
Regards,
Henry
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Ok, thanks Henry and others. As VZ stated. Will be replaced.
Havent had the hood open in a while, nothing from the outside could have done that...like something physically hitting it. I think something protruded from within. Weird thing is, engine runs great and not a drop of fuel comes out. Drove around all day with the jb weld on it. Already ordered a new AC Delco replacement. Good for another 40 yrs.
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After a long procrastination period, finally installed the new ac delco fuel pump. No problems except a bruised rib leaning over the fender. Weird..truck runs even smoother, makes no sense.
(https://uploads.tapatalk-cdn.com/20180919/7c2ba45aec60f95696cbbe30fd6be6de.jpg)
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Hi Philo:
Good to hear you installed a new pump and everything is kosher. If it runs smoother now I would expect that was because your old pump was working, but probably not delivering spec amount of fuel, so the carb was a little bit starved. Do you still have the "holed" pump?...I bet it was just a return spring that broke inside that prevented the pump from delivering a full charge. Sometimes it amazes me the things that can go wrong on a Chevy 350 and it still runs.
Regards,
Henry
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Why the rubber hose? What happened to the steel line?
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Why the rubber hose? What happened to the steel line?
I never changed any hoses at all. Just swaped the pump only. When you installed the new engine, thats how you had it. Why? Should i replace the rubber with stainless steel?
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i noticed there appears to be thread sealant on the fitting that goes into the pump. Is this necessary?
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You've got something going on there. A hole appeared in the pump, steel line became rubber hose. Did you take it somewhere for work? I would never replace the steel line with a rubber hose, use teflon tape etc.... hence the question.
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Vile,
What type of sealant, if any, would you recomend instead of the teflon tape?
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You've got something going on there. A hole appeared in the pump, steel line became rubber hose. Did you take it somewhere for work? I would never replace the steel line with a rubber hose, use teflon tape etc.... hence the question.
Looks to me that rubber hose connects the steel fuel line from the frame to the pump. Teflon tape is not needed on the other fitting.
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When you installed the new engine, thats how you had it.
In the first pic there is a steel line, in the replacement pump pic it is a rubber hose attached to the steel line. I'm assuming whoever replaced your pump tweaked the steel line.
Vile,
What type of sealant, if any, would you recomend instead of the teflon tape?
No sealant is required
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Flare fittings seal through the fit and crush of the flared faces against one another. The threads of the fittings have no bearing on the seal of the connection. However, if the shape and fit of the flares are imperfect, a good seal can be compromised. Typically, tightening the flares sufficiently will overcome minor imperfections causing the faces to conform to one another - one of the advantages of soft steel tubing. In difficult cases, lapping or replacement of the flares becomes necessary. Before going to that extreme, two wraps of Teflon tape around a tubing nut lubricate the threads decreasing friction, thus, the required torque to seal the flares. This allows the line nut to be tightened sufficiently to compress the flares together with greater force without distorting the hollow line nut.
So, the application of Teflon tape to the threads doesn't seal anything. It simply helps to prevent crushing of the line nut.
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Ok, with all that said:
I would never take this kind of job to a shop, i used a couple wraps of teflon tape probably out of force of habit on threaded stuff that fluid flows through, i never added or removed rubber or metal lines..just swaped the pump as is. I did however cut the long rubber hose from steel line to carb to neaten it up a bit, and maybe very slightly bend the line for a neat better fit. No leaks-runs superior.
Oh, and i painted the line black so it looks much better now.