Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 15-08-2015, 07:29   #1
Registered User

Join Date: Dec 2011
Location: Boston Area
Boat: Beneteau 423
Posts: 223
How can I stop diesel leak at sender unit?

I have a plastic diesel fuel tank that has developed a leak at the sender. The problem seems to be caused by one of the screws that has stripped the hole in the tank and won't bite. Other screws are secure. I saw some suggestions of creating a backing plate but I'm not in a position to do that at this point so am looking for an interim solution.

I am thinking of
1. Using a small amount of 4200 to seal the screw hole.
2. Apply 4200 around the sender to seal the leak between the tank and the sender plate.

Is 4200 the right stuff to use? Will it seal from the outside? I'm concerned about the 4200 coming off the screw and ending up in my fuel line, though hopefully the primary filter would pick it up.

Do you have any other alternative approaches?

Thanks,
Harry
__________________

__________________
hlev00 is offline   Reply With Quote
Old 15-08-2015, 09:13   #2
Guy
Registered User

Join Date: Feb 2013
Location: So. Oregon, USA
Boat: Seafarer36c
Posts: 4,308
Re: How can I stop diesel leak at sender unit?

Use a tooth pick or something small and spread the sealant evenly inside the threaded hole. This should keep any excess from falling off the end of the screw inside. With a plastic tank you choice of sealant is a bit more tricky. I think you should make sure it's a polysulfide of some sort.
One trick is to make a small seal from a washer and an O ring. It's called a Lock O seal. You can make your own by using a flat washer that is bigger than the screw and put a small O ring in the middle. When you tighten up, the oversize washer keeps the O ring from squishing out. The sealant should keep the screw tight and the seal will keep it from leaking.
__________________

__________________
Guy is offline   Reply With Quote
Old 15-08-2015, 10:01   #3
Senior Cruiser

Cruisers Forum Supporter

Join Date: Mar 2014
Location: Anacortes
Boat: previous - Whitby 42 new - Goldenwave 44
Posts: 1,735
Re: How can I stop diesel leak at sender unit?

Good luck with any sealant if diesel is already present. And I don't think 4200 will work on your plastic tank material. Do a search on repairs to poly tanks. There was just a long thread on that. The diesel just complicates things.
__________________
exMaggieDrum is offline   Reply With Quote
Old 15-08-2015, 12:16   #4
Moderator
 
cabo_sailor's Avatar

Cruisers Forum Supporter

Join Date: Mar 2008
Location: Tarpon Springs FL
Boat: Cabo Rico 38
Posts: 1,905
Re: How can I stop diesel leak at sender unit?

Can't you just replace the stripped out screw with a slightly larger one?


Sent from my iPhone using Cruisers Sailing Forum
__________________
cabo_sailor is offline   Reply With Quote
Old 15-08-2015, 12:49   #5
Senior Cruiser

Cruisers Forum Supporter

Join Date: May 2013
Location: Oregon to Alaska
Boat: Wheeler Shipyard 83' ex USCG
Posts: 1,708
Re: How can I stop diesel leak at sender unit?

Most auto supply stores have rethreading kits that include a tap, drill and a bushing that has threads that are the same thread as the screw inside and threads to match the tap on the outside. You drill the hole oversize and then tap and install the threaded insert. Use loctite or similar to adhere insert to tank. Diesel shouldn't be a problem unless tank is full. Use acetone to clean threads of diesel if necessary. Insert is usually stainless and lasts the life of the tank.
__________________
Lepke is offline   Reply With Quote
Old 15-08-2015, 12:56   #6
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,365
Re: How can I stop diesel leak at sender unit?

Quote:
Originally Posted by cabo_sailor View Post
Can't you just replace the stripped out screw with a slightly larger one?


Sent from my iPhone using Cruisers Sailing Forum
This. Run the next size tap drill thru. Tap the hole, put a screw with the seal on the screw head in from the inside out. You now have a stud sticking up thru the tank top. Put a nut on the stud on top of your sender.

or if the old screw bites at all, just put it in from the inside of the tank out as a stud.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 15-08-2015, 13:20   #7
Moderator
 
cabo_sailor's Avatar

Cruisers Forum Supporter

Join Date: Mar 2008
Location: Tarpon Springs FL
Boat: Cabo Rico 38
Posts: 1,905
Re: How can I stop diesel leak at sender unit?

Quote:
Originally Posted by Cheechako View Post
This. Run the next size tap drill thru. Tap the hole, put a screw with the seal on the screw head in from the inside out. You now have a stud sticking up thru the tank top. Put a nut on the stud on top of your sender.

or if the old screw bites at all, just put it in from the inside of the tank out as a stud.

If you're installing a bolt, why do you need to tap the hole. I can also see the possibility that due to baffles or some such access to the tank interior may be problematic.

Your choice or mine might work. Frankly I like yours better. Just a question of access I guess. I don't know where his sender is located.

Rich


Sent from my iPhone using Cruisers Sailing Forum
__________________
cabo_sailor is offline   Reply With Quote
Old 15-08-2015, 13:43   #8
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,365
Re: How can I stop diesel leak at sender unit?

Quote:
Originally Posted by cabo_sailor View Post
If you're installing a bolt, why do you need to tap the hole. I can also see the possibility that due to baffles or some such access to the tank interior may be problematic.

Your choice or mine might work. Frankly I like yours better. Just a question of access I guess. I don't know where his sender is located.

Rich


Sent from my iPhone using Cruisers Sailing Forum
So it doesn't fall into the tank when you take the nut off! Hopefully there is an access plate, but could be done thru the sender hole too.
I made a tank once and did it this way on the access cover, if the bolt threads strip it's replaceable. If the hole strips on the other style of tank... more trouble.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 16-08-2015, 08:46   #9
Registered User

Join Date: Dec 2011
Location: Boston Area
Boat: Beneteau 423
Posts: 223
Re: How can I stop diesel leak at sender unit?

Thanks for all the suggestions. I am trying Cabo's suggestion of the larger self tapping screw. I might have needed to drill out the top metal ring as i'm not sure if the screw is drawing the tank up to the sender unit. I don't have an inspection port but might still be able to try Cheechako's stud idea. We had lots of rolling and bouncing beating yesterday. I will check the tank later today to see how the screw worked.

Thanks all!



Sent from my iPad using Cruisers Sailing Forum
__________________
hlev00 is offline   Reply With Quote
Old 16-08-2015, 10:29   #10
Registered User

Join Date: Jul 2015
Location: Ft. Lauderdale, FL
Boat: various over the years
Posts: 53
Re: How can I stop diesel leak at sender unit?

For a sealant on fuel system items, try Permatex no 2. available at auto parts stores.

Permatex is resistant to gasoline and diesel. Many other "marine" grade sealants are not.
__________________
ex-12m-guy is offline   Reply With Quote
Old 16-08-2015, 11:17   #11
Registered User

Join Date: Jun 2015
Location: Houston
Boat: Beneteau Cyclades 51.4
Posts: 213
Images: 1
Re: How can I stop diesel leak at sender unit?

Careful using sealants in diesel tank. I chased when in Grenada a couple of years ago a ghost of lack of diesel flow to my genie It ended up been a sealant plug in the sending unit. Easy to fix expensive in money and time to find it. Find a larger screw no sealants
__________________
sailon46 is offline   Reply With Quote
Old 16-08-2015, 14:10   #12
Senior Cruiser
 
Jim Cate's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 11,461
Re: How can I stop diesel leak at sender unit?

Quote:
Originally Posted by ex-12m-guy View Post
For a sealant on fuel system items, try Permatex no 2. available at auto parts stores.

Permatex is resistant to gasoline and diesel. Many other "marine" grade sealants are not.
Agreed! Good old Permatex sealed just such a leak for us at sea in nasty conditions some years ago... simply slathered on from the outside.

Sometimes the old stuff is the good stuff!

Jim
__________________
Jim and Ann s/v Insatiable II , lying Port Cygnet, Tasmania once again
Jim Cate is offline   Reply With Quote
Old 16-08-2015, 14:18   #13
Registered User

Join Date: Oct 2011
Location: St Petersburg, FL
Boat: Kanter Yachts Steel Spray 38
Posts: 56
Re: How can I stop diesel leak at sender unit?

Quote:
Originally Posted by Lepke View Post
Most auto supply stores have rethreading kits that include a tap, drill and a bushing that has threads that are the same thread as the screw inside and threads to match the tap on the outside. You drill the hole oversize and then tap and install the threaded insert. Use loctite or similar to adhere insert to tank. Diesel shouldn't be a problem unless tank is full. Use acetone to clean threads of diesel if necessary. Insert is usually stainless and lasts the life of the tank.
You can search for either "Threaded Inserts" or Helicoils for the product...
__________________
TKDSailor is offline   Reply With Quote
Old 16-08-2015, 16:04   #14
Registered User

Join Date: Dec 2011
Location: Boston Area
Boat: Beneteau 423
Posts: 223
Re: How can I stop diesel leak at sender unit?

Quote:
Originally Posted by TKDSailor View Post
You can search for either "Threaded Inserts" or Helicoils for the product...

I have a plastic tank. I wouldn't have thought the thread inserts would be useful.


Sent from my iPhone using Cruisers Sailing Forum
__________________
hlev00 is offline   Reply With Quote
Old 16-08-2015, 16:21   #15
Registered User
 
sanibel sailor's Avatar

Join Date: Feb 2013
Location: Sanibel FL
Boat: 1979 Bristol 35.5 CB
Posts: 978
Re: How can I stop diesel leak at sender unit?

Threaded inserts are designed for metal, doubt it would work on plastic. A riv-nut works on plastic, but would stick up and prohibit a good seal. Permatex #2 is a godsend. The only stuff it does not work well for is alcohol. Probably not much help if the screw does not bite however. Goop outside the leak is rarely successful. If using a bigger screw (easiest approach), you will need to drill the plate on the sender a bit oversize so the screw will compress the gasket. Do not drill down into the tank with that bit. Also, if you are removing the sender, make sure you know which is the correct hole. The pattern is an SAE standard and only lines up one way. Good news is that you can pick up a new gasket at any auto part store.
__________________

__________________
John Churchill Sanibel FL
NURDLE, 1979 Bristol 35.5 CB
sanibel sailor is offline   Reply With Quote
Reply

Tags
diesel

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Wanted: Yanmar 2QM20 Tachometer and Sender Unit (or replacements) wilrog Engines and Propulsion Systems 2 20-07-2014 16:44
Isotherm Freezer - Run, Stop, Run, Stop... Cruisin Cat Electrical: Batteries, Generators & Solar 8 24-04-2014 19:06
What islands to stop at and what islands not to stop at that is the question?Carib- Ram Atlantic & the Caribbean 11 21-05-2012 18:57
Perkins 4.108 Oil Pressure Sender Unit Alan B Engines and Propulsion Systems 3 06-07-2010 17:20
Perkins 4.108 Formosa 41 Oil Sender Unit Alan B Engines and Propulsion Systems 4 02-06-2010 17:23



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 08:51.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.