Welch Plugs, Freeze Plugs - a Primer
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=17461
Printed Date: 05 Feb 2025 at 11:03pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Welch Plugs, Freeze Plugs - a Primer
Posted By: CJohnS MI
Subject: Welch Plugs, Freeze Plugs - a Primer
Date Posted: 30 Aug 2010 at 10:18pm
|
Welch Plugs. Expansion Plugs, Freeze Plugs, Disc Expansion Plugs, Cup Expansion Plugs - even sometimes misspelled as "Welsh" plugs. They came about as an answer for the need to cheaply and reliably seal the ends of bore holes, and do it without taking up a lot of room, or requiring exotic materials. On the WD 45 for example, they can be found at: 1. The sand cast ports in the bottom of the head (famous for rusting out) 2. Back of block where the rearmost camshaft bearing sits 3. Transmission cover where the shift rails fit. Welch plugs get their "Freeze Plug" nickname because they are used so often to seal the holes left behind that are needed to extract the sand from engine block castings. This usually is a problem where the water jacket around the cylinders is formed. And when someone makes the mistake of using no antifreeze - or too little of it - those plugs will pop right out with the first cold snap. The Wd 45 engine doesn't use freeze plugs for the water jackets, because it uses "wet sleeves". There's no cylinder bore to get in the way of extracting the casting sand when the engine block is poured. But its OK to call them "freeze plugs - they been carrying that nickname for about 100 years now - much as circular saws are called "Skil Saws". The more important thing to remember is that the guy at the parts counter likely will not know what the heck you are talking about, so it may be a good idea to memorize ALL the possible name choices. Welch Plugs are a truly American Invention. Not only that, but they are a Michigan invention, first made in Pontiac, and now Oxford. Fact is, the original company still produces them and are located about 1500 hundred feet from my favorite breakfast joint. Here's the the facts, as told by the Great Grandson of the company that originally manufactured them: Brief History of the Welch Plug by Nevin Hubbard of www.hubbardspring.com A brief bit of totally obscure history that I am one of the few living persons who knows. My family business, established in Pontiac, Michigan in 1905, is the original manufacturer of the "Welch" plug. The Welch brothers had a motor car company at the turn of the century that was later bought by General Motors - the Welch Motor Car company. They would run the cars around Pontiac to "break them in." At that time core holes in the engine blocks were fitted with pipe plugs. During one of these run-ins a pipe plug backed out. In order to get back on the road one of the brothers drove a quarter or half dollar into the hole. From this they developed the Welch plug, some with the help of my Great Grandfather Martin Hubbard. They then patented the plug and the M.D. Hubbard Spring Company become the sole manufacturer of the Welch plug for the life of the patent. To this day we have the largest range of sizes available anywhere. So the Welch plug in origin is an American innovation and name. Best Regards, Nevin Hubbard M.D. Hubbard Spring Company www.hubbardspring.com There's a couple of excellent sources for plugs: The best of course is Hubbard Spring, which has the broadest range and greatest experience in properly installing them. http://www.hubbardspring.com - http://www.hubbardspring.com A second, widely distributed product range is Dorman Products (they've been around since 1918) and their famous trays pf fasteners can be found in most quality, full-line hardware stores. http://www.dormanproducts.com/c-238-concave-expansion-plugs.aspx - http://www.dormanproducts.com/c-238-concave-expansion-plugs.aspx Whether you get expansion plugs from the tractor dealer or one of the sources above, do yourself a favor, go to the Hubbard Spring site and read the installation guides they provide. There are as many wrong ways to install these plugs as there are so-called "Experts". The most important things to remember (and there are only three): 1. You are working on a not-new piece of machinery, so clean, and clean again. And then inspect the bore. Make sure past leaks or damage caused by extracting the old plug haven't eroded or scored the seating surface. 2. Use a sealant - and use the CORRECT sealant. Permatex #2 works well, and so does Permatex #1 (hardening) in most water environments. Materials like RTV - are NOT good - they actually will help that plug to pop out. Just the slightest coating on the side wall of the bore where the shoulder of the disc meets it will do. 3. Use the right driving tool. Hubbard Spring goes to great length to accurately describe the proper tool for use in a manufacturing process. BUT - you are not a manufacturer. The best "tool" it turns out is often the drive side of a socket that is slightly smaller that the diameter of the expansion plug. Take your time to set the plug into the bore and make sure it is bottomed, set the "drive tool" squarely to it, and rap it hard enough to cause that disc to compress to nearly flat. Don't bother trying to use something much smaller and "tapping all around it" - you'll end up with a disc that looks like it lost a war, and will just drop out of the hole. Well, there you go - a bit of enduring American history and technology - and still relevant today. |
Replies:
Posted By: Coke-in-MN
Date Posted: 30 Aug 2010 at 10:44pm
|
On the convex plugs (disc) they set into a slight counterbore in casting and when installing them I use a large ballpeen hammer set in center of plug , then strike with another hammer to seat plug to counterbore of hole , this expands disc to seal tight. ------------- Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something. "Challenges are what make life interesting; overcoming them is what makes life meaningful." |
Posted By: GlenninPA
Date Posted: 31 Aug 2010 at 3:00pm
|
Did Allis source from Hubbard or Dorman? or both? Anybody know?
My guess is probably both, that was the thing to do in the day.....
|
Posted By: Chris/CT
Date Posted: 31 Aug 2010 at 7:29pm
| I just removed one from the end of the PD cross bar in the torque housing on WD-45. |
Posted By: LouSWPA
Date Posted: 31 Aug 2010 at 7:37pm
|
As far as "popping" out to save engine block in the event of water in jacket, it's been my experience that they do pop out right after the block cracked! In fact, I always half joked that it was the block cracking that relieved the grip on the plug ------------- I am still confident of this; I will see the goodness of the Lord in the land of the living. Wait for the Lord; be strong and take heart and wait for the Lord. Ps 27 |
Posted By: CJohnS MI
Date Posted: 31 Aug 2010 at 7:43pm
Lou, I'm with you on that! |
LouSWPA wrote: