Spun threads out of gas tank. Anyone reinstall them successfully?
03-27-2017, 07:58 PM
#1
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Spun threads out of gas tank. Anyone reinstall them successfully?
Welp, the worst happened in regards to fuel tank issues. The threads came loose while reinstalling. Apparently 19ft/lbs is too much for my 28y/o tank.
Anyone successfully reinstall the threads back into the tank and if so, what did you use and what was your technique?
Thanks,
Rich
Anyone successfully reinstall the threads back into the tank and if so, what did you use and what was your technique?
Thanks,
Rich
03-27-2017, 08:23 PM
#2
Rennlist Member
Welp, the worst happened in regards to fuel tank issues. The threads came loose while reinstalling. Apparently 19ft/lbs is too much for my 28y/o tank.
Anyone successfully reinstall the threads back into the tank and if so, what did you use and what was your technique?
Thanks,
Rich
Anyone successfully reinstall the threads back into the tank and if so, what did you use and what was your technique?
Thanks,
Rich
A search for "fuel tank insert" works pretty well. Here's a start:
https://rennlist.com/forums/928-foru...al-thread.html
https://rennlist.com/forums/928-foru...-pointers.html
https://rennlist.com/forums/928-foru...t-be-done.html
https://rennlist.com/forums/928-foru...l#post11611542
https://rennlist.com/forums/928-foru...er-or-not.html
03-27-2017, 10:03 PM
#3
Chronic Tool Dropper
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Recovered from another thread:
Some thoughts from the experience with Jim Chambers' car here a month ago.
-- Inspect through the level sender opening. If the screen is intact (and yours appears to be intact) and there are no external leaks, be happy, live long and prosper.
-- If you do decide to remove the strainer, follow Jim Corenman's advice with the socket, at minimum. Using a Crescent or even the "proper" box wrench applies a lot of lateral force to the connection, when you really want just twisting. Lateral force adds to the chance of distorting or straining the bond between the plastic and the threaded insert.
-- Follow the guidance on freezing the strainer insert. Easy options include "canned air" with the can inverted, same but with refrigerant or other freeze spray, or dry ice per the previous suggestions.
-- Confirming GJB's info, that "gap" between the tank neck and the screw-in fitting is supposed to be occupied by a rubber-like seal. In Jim Chambers' car, that seal had completely disintegrated and scattered as orange dust. That seal is what's supposed to keep the fuel inside the tank, although the corrosion in the threads often seems to supplement that sealing.
-- Contrary to GJB's info, we did not find any holes or plastic pins designed to retain the screw-in piece to the tank insert. The steel tank insert itself has holes in it that are filled with plastic from the tank molding process, probably to keep it from turning. Those holes and the plastic in them are deeper in the insert than the threads on the screw-in piece will reach, so won't interfere with removing or installing the thread-in piece.
----
The aluminum screw-in piece on Jim Chambers' tank was corroded quite well to insert. Impact and long-handled bar with socket ended up spinning the insert in the tank, so both pieces were removed together for more work on the bench.
The tank itself was fine with the pieces removed. Jim did a bunch of cleanup of the tank, including the nose where the insert lives. While he worked on that, I made a clamping fixture to hold the insert piece in the vise without distorting or collapsing it. The corrosion bond was so strong that even with a week of soaking in ATF/Acetone mix, it wouldn't budge. I ended up twisting the hex and rounding it, even with a six-point socket. The aluminum hex parts sheared off, leaving an ugly torn area that guaranteed that replacement was the only option. At that point I drilled out the hole in the middle, big enough to push a hacksaw blade through. Fitted the blade to a saw frame and carefully made radial cuts in the aluminum out to the steel tank insert threads. A couple intersecting cuts allowed me to collapse the aluminum from the steel, and from there extraction was no problem.
The steel insert was given a bath in a rust remover for a bit to get all the obvious corrosion removed. The sleeve was then cleaned thoroughly in prep for reinsertion.
I made a small "press" tool from a piece of 3/8" all-thread and some nuts and washers. I found that a 3/8" fender washer in my collection has the same OD as the tank insert, while a 1/2" USS flat washer OD is a perfect fit inside the steel tank insert. Some other hardware-bin bearing-retainer washers happened to be the right ID to fit over the flange lip at the end of the tank nozzle/neck, so we had a way to keep the sleeve square to the "puller", plus a way to keep the pressure at the outside end limited to the area around that flange lip without collapsing the lip or the nozzle flange area.
With everything clean, we applied a thin but continuous coating of J-B Weld to both the inside of the tank and the outside of the insert. I added some mechanic's wire to each end of the all-thread rod, secured with wire ties, then passed the tool and the insert into the tank via the level sender hole, after threading the pull wire out through the bottom opening. The wire on the back end was used to guide the insert into position in the tank outlet nozzle. Then nuts were tightened on the all thread and washers stack to draw the sleeve in, perfectly square with the face and firmly up against the flanged end of the tank nozzle. We left the tool in there with tension on it for a day while the epoxy set up, then removed it by pulling on the back-end wire and out through the sender opening.
The new strainer and fitting were carefully prep'd with Teflon-based pipe sealing paste on the threads, and Hylomar sealer on the neoprene seal itself and the tank flange and lip. The strainer went in painlessly. We snugged it up enough to seat the gasket well but not much more, then leak-tested by putting a little fuel back into the tank after installation. After a leak-free day, Jim added more fuel to further the test, and again no leaks for a few days of observation. We called it good and finished the installation with new GB hoses, a new pump and filter, and finally the pump cover, down from the lift, and a test drive. Success!
---
Marine Sta-Bil has some good features, including mopping up moisture from ethanol-added fuels that will otherwise corrode aluminum and some steel parts in the fuel system. I strongly recommend that folks use that, especially for cars that are driven less than regularly. The water settles out over time, and ends up puddling under the fuel right at the strainer connection in the bottom of the tank. Anyway, some simple care with the right fuel preservative can help you avoid this and other corrosion-related fuel system maladies.
I'll add pictures and a more complete write-up to Jim Chambers' fuel tank thread soon.
I don't remember if I actually updated his thread as promised. I'm not near the garage right now so no pics of the little tool we made to pull the sleeve back in. It worked really well, if you can go by the description.
Originally Posted by dr bob
Some thoughts from the experience with Jim Chambers' car here a month ago.
-- Inspect through the level sender opening. If the screen is intact (and yours appears to be intact) and there are no external leaks, be happy, live long and prosper.
-- If you do decide to remove the strainer, follow Jim Corenman's advice with the socket, at minimum. Using a Crescent or even the "proper" box wrench applies a lot of lateral force to the connection, when you really want just twisting. Lateral force adds to the chance of distorting or straining the bond between the plastic and the threaded insert.
-- Follow the guidance on freezing the strainer insert. Easy options include "canned air" with the can inverted, same but with refrigerant or other freeze spray, or dry ice per the previous suggestions.
-- Confirming GJB's info, that "gap" between the tank neck and the screw-in fitting is supposed to be occupied by a rubber-like seal. In Jim Chambers' car, that seal had completely disintegrated and scattered as orange dust. That seal is what's supposed to keep the fuel inside the tank, although the corrosion in the threads often seems to supplement that sealing.
-- Contrary to GJB's info, we did not find any holes or plastic pins designed to retain the screw-in piece to the tank insert. The steel tank insert itself has holes in it that are filled with plastic from the tank molding process, probably to keep it from turning. Those holes and the plastic in them are deeper in the insert than the threads on the screw-in piece will reach, so won't interfere with removing or installing the thread-in piece.
----
The aluminum screw-in piece on Jim Chambers' tank was corroded quite well to insert. Impact and long-handled bar with socket ended up spinning the insert in the tank, so both pieces were removed together for more work on the bench.
The tank itself was fine with the pieces removed. Jim did a bunch of cleanup of the tank, including the nose where the insert lives. While he worked on that, I made a clamping fixture to hold the insert piece in the vise without distorting or collapsing it. The corrosion bond was so strong that even with a week of soaking in ATF/Acetone mix, it wouldn't budge. I ended up twisting the hex and rounding it, even with a six-point socket. The aluminum hex parts sheared off, leaving an ugly torn area that guaranteed that replacement was the only option. At that point I drilled out the hole in the middle, big enough to push a hacksaw blade through. Fitted the blade to a saw frame and carefully made radial cuts in the aluminum out to the steel tank insert threads. A couple intersecting cuts allowed me to collapse the aluminum from the steel, and from there extraction was no problem.
The steel insert was given a bath in a rust remover for a bit to get all the obvious corrosion removed. The sleeve was then cleaned thoroughly in prep for reinsertion.
I made a small "press" tool from a piece of 3/8" all-thread and some nuts and washers. I found that a 3/8" fender washer in my collection has the same OD as the tank insert, while a 1/2" USS flat washer OD is a perfect fit inside the steel tank insert. Some other hardware-bin bearing-retainer washers happened to be the right ID to fit over the flange lip at the end of the tank nozzle/neck, so we had a way to keep the sleeve square to the "puller", plus a way to keep the pressure at the outside end limited to the area around that flange lip without collapsing the lip or the nozzle flange area.
With everything clean, we applied a thin but continuous coating of J-B Weld to both the inside of the tank and the outside of the insert. I added some mechanic's wire to each end of the all-thread rod, secured with wire ties, then passed the tool and the insert into the tank via the level sender hole, after threading the pull wire out through the bottom opening. The wire on the back end was used to guide the insert into position in the tank outlet nozzle. Then nuts were tightened on the all thread and washers stack to draw the sleeve in, perfectly square with the face and firmly up against the flanged end of the tank nozzle. We left the tool in there with tension on it for a day while the epoxy set up, then removed it by pulling on the back-end wire and out through the sender opening.
The new strainer and fitting were carefully prep'd with Teflon-based pipe sealing paste on the threads, and Hylomar sealer on the neoprene seal itself and the tank flange and lip. The strainer went in painlessly. We snugged it up enough to seat the gasket well but not much more, then leak-tested by putting a little fuel back into the tank after installation. After a leak-free day, Jim added more fuel to further the test, and again no leaks for a few days of observation. We called it good and finished the installation with new GB hoses, a new pump and filter, and finally the pump cover, down from the lift, and a test drive. Success!
---
Marine Sta-Bil has some good features, including mopping up moisture from ethanol-added fuels that will otherwise corrode aluminum and some steel parts in the fuel system. I strongly recommend that folks use that, especially for cars that are driven less than regularly. The water settles out over time, and ends up puddling under the fuel right at the strainer connection in the bottom of the tank. Anyway, some simple care with the right fuel preservative can help you avoid this and other corrosion-related fuel system maladies.
I'll add pictures and a more complete write-up to Jim Chambers' fuel tank thread soon.
I don't remember if I actually updated his thread as promised. I'm not near the garage right now so no pics of the little tool we made to pull the sleeve back in. It worked really well, if you can go by the description.
03-27-2017, 11:18 PM
#4
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03-27-2017, 11:46 PM
#6
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Welp, the worst happened in regards to fuel tank issues. The threads came loose while reinstalling. Apparently 19ft/lbs is too much for my 28y/o tank.
Anyone successfully reinstall the threads back into the tank and if so, what did you use and what was your technique?
Thanks,
Rich
Anyone successfully reinstall the threads back into the tank and if so, what did you use and what was your technique?
Thanks,
Rich
Except there is no glue or epoxy that will "melt" the plastic and actually bond the insert to the tank.
Just never park your car in a building that is attached to where you sleep and you will be fine.
03-28-2017, 12:06 AM
#7
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Good job, Eric... your post made Dr Bob's appear for me (as well as yours).
IB didn't do a recent update, did they?
IB didn't do a recent update, did they?
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03-28-2017, 12:26 AM
#9
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Same thing happened to me a few years ago when I first started working on my 928 project (still ongoing). I spun the insert trying to remove the clogged up strainer.
I did lots of reading on this forum and others and the general wisdom is to use epoxy and cross your fingers. The problem is that these tanks are made of HDPE ("Lupolen 4261 A"), and nothing sticks well to it, even epoxy. I searched and searched for a suitable HDPE adhesive but never found anything I could be confident would hold in the long run. Some guys have had success with PC7/11 epoxy but I did not get good results when I tested it.
I thought about it for a LONG time and then it hit me...HEAT! These tanks are plastic and the HDPE flows at a fairly low temp (about 200-ish degF iirc). Some guys have successfully plastic welded a crack or scratch, but I didn't have luck just heating the plastic around the insert.
The thing about HDPE is you can't just heat and weld it because HDPE only mixes and flows correctly when it's under pressure. So I heated up the tank outlet and the insert and reinstalled it, using a jig to hold everything together and a clamp to apply some pressure to the outside of the outlet to cause the plastic to flow.
There were a couple of kinks in the process as I figured out what to do, and some things I would probably do differently, but in the end it worked like a champ and is nice and firmly held in place again (going on 3+ years).
But you MUST BE CAREFUL! Heat + Gas = Bad. My tank was out of the car and had not had any real (ie - volatile) gas in it for a very long time. Plus I rinsed and washed it out a ton before doing anything. So in my case there was no chance of gas vapors igniting because there weren't any.
I don't think I would try this if the tank were still in the car because of access issues. Maybe on a lift would work, but only if I could be 100% sure all the fumes were gone.
And most important...knowing what I know now I would try some of the well-documented tricks and techniques to try and loosen up the insert before removing it (See the links in Jim's post above). (hindsight = 20/20)
But if it does spin I like my fix best of all the ones I've read about so far. I took some pix...I'll try to find them and post them.
-Ted
(My first post after several years and lots of reading and learning. Many thanks to everyone here for all their wisdom!)
I did lots of reading on this forum and others and the general wisdom is to use epoxy and cross your fingers. The problem is that these tanks are made of HDPE ("Lupolen 4261 A"), and nothing sticks well to it, even epoxy. I searched and searched for a suitable HDPE adhesive but never found anything I could be confident would hold in the long run. Some guys have had success with PC7/11 epoxy but I did not get good results when I tested it.
I thought about it for a LONG time and then it hit me...HEAT! These tanks are plastic and the HDPE flows at a fairly low temp (about 200-ish degF iirc). Some guys have successfully plastic welded a crack or scratch, but I didn't have luck just heating the plastic around the insert.
The thing about HDPE is you can't just heat and weld it because HDPE only mixes and flows correctly when it's under pressure. So I heated up the tank outlet and the insert and reinstalled it, using a jig to hold everything together and a clamp to apply some pressure to the outside of the outlet to cause the plastic to flow.
There were a couple of kinks in the process as I figured out what to do, and some things I would probably do differently, but in the end it worked like a champ and is nice and firmly held in place again (going on 3+ years).
But you MUST BE CAREFUL! Heat + Gas = Bad. My tank was out of the car and had not had any real (ie - volatile) gas in it for a very long time. Plus I rinsed and washed it out a ton before doing anything. So in my case there was no chance of gas vapors igniting because there weren't any.
I don't think I would try this if the tank were still in the car because of access issues. Maybe on a lift would work, but only if I could be 100% sure all the fumes were gone.
And most important...knowing what I know now I would try some of the well-documented tricks and techniques to try and loosen up the insert before removing it (See the links in Jim's post above). (hindsight = 20/20)
But if it does spin I like my fix best of all the ones I've read about so far. I took some pix...I'll try to find them and post them.
-Ted
(My first post after several years and lots of reading and learning. Many thanks to everyone here for all their wisdom!)
03-28-2017, 12:48 AM
#11
Rennlist Member
My original tank was cracked when I bought the car and I had success in repairing it with plastic welding only to have the threads start leaking later same as yours.
I never repaired the threads since I found a used tank.
My plan was to put a hose clamp over the thread area and heat it up with the plastic welder until the plastic get soft and let it cool with some "pressure" applied with the hose clamp. I'm 100% sure this will work but haven't tried it yet.
I never repaired the threads since I found a used tank.
My plan was to put a hose clamp over the thread area and heat it up with the plastic welder until the plastic get soft and let it cool with some "pressure" applied with the hose clamp. I'm 100% sure this will work but haven't tried it yet.
03-28-2017, 02:11 AM
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ps, dear Rob, I plan to renew a new two year membership soon, please be patient., thanks.
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03-28-2017, 11:44 AM
#13
Chronic Tool Dropper
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So the epoxy for the sleeve into the tank isn't to seal it there, only to hold the sleeve in place so you can install and remove the strainer (or in-tank pump) fitting. When installed, the sleeve needs to support the lip at the end of the tank nozzle opening, since that's where the sealing is actually done. There's a soft round gasket that fits in the groove in the screw-in fitting, seats and seals to the lip on the tank there. Having the sleeve in the right place means that a small amount of tension on the threads will seat that gasket correctly, square to the face of the nozzle and the lip formed at the end.
-----
When I first posted a reply, Jim C's post from a couple hours earlier wasn't visible.
-----
When I first posted a reply, Jim C's post from a couple hours earlier wasn't visible.
03-28-2017, 11:48 AM
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03-28-2017, 01:32 PM
#15
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I find the best way to fix this is to have the tank out of the car, then heat the collar back up with a torch, and put it back in hot. This will allow the plastic to reattach to it. Not easy to do. But the best way to do it IMO.