Drain plug holes rusted...
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=10796
Printed Date: September-29-2024 at 7:23am
Topic: Drain plug holes rusted...
Posted By: kraftchick
Subject: Drain plug holes rusted...
Date Posted: June-10-2008 at 2:22pm
| The drain plug holes including the exhaust manifold plug holes are all rusted out on my '91 SN. Each year when I put the plugs in, I have to wrap them with teflon tape to get any kind of bite on what's left of the threads (barely any) on the drain plug holes to get them to seal. Any idea on how to repair this and get the correctly sized drain plugs ? |
Replies:
Posted By: 79nautique
Date Posted: June-10-2008 at 2:35pm
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if they are stripped in the block then you have major troubles fixing those, the ones in the exhaust well you have to replace them, hadr to tap castiron and I don't know if there is enough area to inlarge then to the next size.
Now you do need to stop using galvinized plugs and start using brass like youe suppose too. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: kraftchick
Date Posted: June-10-2008 at 2:49pm
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I'm still using the brass plugs on both the block and the exhaust...unfortunately both the hole threads and the plug threads are in bad shape. Is there any possible way to fix the ones in the block ? Any when you say replace the ones in the exhaust, are you meaning replace the manifolds completely ?
Thanks for the quick replies. |
Posted By: 79nautique
Date Posted: June-10-2008 at 2:58pm
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it's unusual that the block drains have issues, but in the future I wouldn't use teflon tape but pipe dope instead this will seal much better and helps prevent water rusting out the threads since it will seal ten times better than the teflon tape ever can. I would get a thread chaser and start there your only possible fix is enlarging the holes and taping new pipe threads. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: 8122pbrainard
Date Posted: June-10-2008 at 3:08pm
Brian, The first thing I would try that Chris mentioned is to try and tap the existing holes deeper. Since pipe threads are tapered, this will usually give you new threads. The down side to this is now the plugs will go deeper into the wall of the engine and manifolds. So the plugs can go deeper, you may want to get some brass socket head plugs.
Manifold replacement is not needed at this time. When tapping the threads, only go deep enough to clean up the threads. Do use teflon tape and don't over tighten the plugs. You are not looking at very much pressure in the cooling system. If this doesn't work, then you would want to re drill and tap to the next size pipe plug if there is enough boss area (the thicker section of casting around the hole) in the casting. Chris, You really must have had a hard time with the tapping of cast iron at one point. I mentioned it before that it really isn't a problem and is done daily. A small amount of kerosene or a very light oil works best to aid the tapping. Edit: Brian, Make sure you have enough depth behind the hole for the tap to go into. If shallow, you may have to make a "bottoming" tap by grinding off some of the tip (length). ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: 79nautique
Date Posted: June-10-2008 at 3:13pm
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it's just brittle stuff and with the teflon tape that will not seal like the pipe thread sealent will and that is why it is rusting because water is wicking up the threads some and rusting them out, using thread sealent aka pipe dope prevents that. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: 8122pbrainard
Date Posted: June-10-2008 at 3:32pm
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Brian, Are you running in salt or brackish water? Has the boat ever been in salt? I'm just trying to figure out why you are having this problem! Chris has a point with the pipe thread sealant possibly giving the threads more corrosion resistance. The very best sealant that I have found is Slic-tite. It's more expensive than others but it does contain Teflon which makes dis assembling pipe a lot easier. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: kraftchick
Date Posted: June-10-2008 at 3:43pm
| No salt or brackish water ever. The only thing I can think of is and this may have been my own doing (or not doing enough in this case)...is at the end of the year, I remove the plugs to let the block drain. I watch it to make sure nothing clogs it up while draining. Once it was through, that was it. There was always a small amount of water that you could still still see inside (just barely a little though)...and over the years that's what has seemed to create the rust in the hole threads. It's also rusty inside their, always has been...I just always thought that was normal. I've always seen rust in there. |
Posted By: 8122pbrainard
Date Posted: June-10-2008 at 3:53pm
|
Brian, It sounds like you just drain the block and manifolds. Although this was common practice for many years, it is now more common to put the plugs back in after draining and get anti freeze down into the block. Since it does have corrosion inhibitors in it, it would help. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: kraftchick
Date Posted: June-10-2008 at 4:00pm
| Pete, you described my practice exactly...that's what I was told...just drain it and you're done. I haven't ever used anti-freeze. With seeing that rust in there, it makes me feel like the lifespan shorter than something that was more well taken care of...just wondering when I'll have issues because of the internal rusting in the water jackets ? Scary ! But, this winter after I get a detached garage built, I'm planning on doing the hull restoration and interior restoration as well. Just waiting till I have somewhere nice to keep it before putting the money into it. Any chance there is anything that might could be run through it to help clean it out some and maybe slow down the death process ? |
Posted By: 8122pbrainard
Date Posted: June-10-2008 at 4:05pm
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Brian, You'll be fine with the internals. It's just the threads that got eaten up because of the small metal cross section (the tiny peaks of the threads). ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: kraftchick
Date Posted: June-10-2008 at 4:12pm
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Thanks Pete ! And Chris ! Strange...after finding this site and all the wealth of info out here, this may be the first time that I'm looking forward to winter for boat reasons...HA ! Can't wait to get this '91 looking like it should !!! I almost sold it a couple of years ago, knowing that I wouldn't be using it that much for a few years...have a 2 1/2 yr. old and another one on the way due in August. Definitely want them growing up on the lake, so I decided to keep it. Now I can take my time over the next couple of years getting it back in tip top shape for when they are ready to be dragged around the lake !
|
Posted By: starbucksdad
Date Posted: June-11-2008 at 5:47pm
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Sounds like it has been a rough winter on drains. I have a 1986 2001, getting ready to tow to local dealer and have block drain redrilled. All threads rusted, have tried everything with no luck. Really hope this cures problem. It the future I have been told to pyt grease on the plugs and put them back in for winter. Good luck... ------------- starbucksdad |
Posted By: 8122pbrainard
Date Posted: June-11-2008 at 7:47pm
What did you end up trying? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
starbucksdad wrote:Posted By: starbucksdad
Date Posted: June-11-2008 at 8:28pm
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I tried rethreading existing hole, new brass plugs,new steel plugs,tape on old plugs, small hammer...... ------------- starbucksdad |
Posted By: 77stang
Date Posted: June-14-2008 at 7:55pm
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hey guys,
good to be logged back on and see all the familiar users. well, i too have a rusted thread drain plug problem. it makes me mad at myself because i've seen it coming for a couple years now and never did change my winterization method to just keeping the plugs in and running antifreeze though the motor. i finally got a new set of plugs to tighten up about 1 and 1/2 turns but thats it - just ran of of taper. guess i'll see what happens ------------- http://correctcraftfan.com/diaries/details.asp?ID=1360&yrstart=1971&yrend=1975 - '77 Mustang 17 |
Posted By: Behl
Date Posted: June-14-2008 at 10:18pm
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I installed the brass and plastic ball valves from skidim. My threads were ok but only have to install one time. Easy to drain and replace with antifreeze ------------- Steve in Indy http://correctcraftfan.com/diaries/details.asp?ID=1702&sort=&pagenum=1&yrstart=1976&yrend=1980" rel="nofollow - Redone 1977 Ski Tique |