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Suggestions on how to remove 1-1/4 pipe plug on 1972 Cadillac engine

Started by colorado4x4, September 24, 2022, 01:18:48 PM

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colorado4x4

Wanting to remove the water outlet plug on the back of the passenger side cylinder head on this 1972 Cadillac 472 engine. and replace it with the water outlet hose fitting so that I can reconnect my heater hoses.  This 1972 engine is from a 1972 Sedan Deville, it is currently in my 1970 Deville. Between 1970 and 1972 they changed where the heater water outlet is routed. In 1970 the outlet was below/near the thermostat housing on the front passenger side of the engine. In 1972 the water outlet was on the back side of the passenger side cylinder head.  The pipe plug has a 1/2 inch female socket, the threaded portion is 1-1/4 inch, so kind of big, relatively speaking.

I put my car up on ramps to get access from underneath to the backside of the passenger side cylinder head to try and remove the water outlet pipe plug.  Have an SKS 1/2 pipe plug socket and a breaker bar, but to no avail was I able to loosen the plug. Tried an impact wrench, still no go.  Called some classic car repair guys I met at an car show a few weeks ago, and took the car to their shop and put it up on the lift to see if a big, longer breaker bar would do the trick with more room for leverage, still no go.

Kind of at a loss of what to do next.... induction heater tool? then wax or acetone/trans fluid soak? As you can see, there are only about three threads from the plug sticking out of the cylinder head, (so the plug is about halfway in, judging by the outlet fitting I want to but in) so not sure if an induction tool would have enough surface area for the coils to wrap around to heat it up.

Remove the head from the engine and try getting the pipe plug out while on a workbench with more room to work? still not sure how to get it out with it on a workbench,...acetylene torch and then wax or acetone/trans fluid soak? Grind a notch in it and try to pound it around with a chisel and hammer?

Any suggestions out there on how to get out of this conundrum?
Rocky Mountain Region Membership Chair & Treasurer
1970 DeVille Convertible Chateau Mauve Firemist
1970 DeVille Convertible Lanai Green Metallic

CadillacFanBob

Could you post a photo of the area you are talking about.

Possibly use a Venum H.P.heat mini ductor and insert the coils inside the fitting of the plug.

Bob
Frankfort, Illinois

Bronze

I personally like heat better than magic oils. They never seem to creep very far in and they don't dissolve the rust. If you can get a torch there remember to heat the block around the plug rather than the plug itself. You want the hole to expand not the plug. The nice thing is that it has a female socket, let the tool you use lie in cold water before so it is as cool as possible, with some luck when you insert the tool in the plug the temp difference might make the plug shrink just a thousand of an inch which may be enough to break the bond. I have also always had more luck with impact rather than a long breaker bar. Banging on the handle of the wrench (in both directions) could help to "shock" it loose. Persistence and patience over brute force is the trick...

dochawk

after struggling with a lugnut on my '72 convertible for years (a couple of chemicals, a breaker bar stressed to flexing, etc.), I doused it with WD-40 Rust Remover (*not* the same thing as regular WD-40!).

48 hour later, it was just another tough lugnut removal.

Also, having recently received some ancient tools of my grandfather, I was introduced to an intriguing ratchet driver.  It is a cylinder, and is activated by *hammering*.  You pound it's end, and it turns the bolt!
1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

colorado4x4

sorry, here are two photos, (uploading photos is now a two step process, in which I missed the second step !

First, the view from underneath looking up to the passenger side cylinder head. The pipe plug is seen with its square socket.
1972 Engine Water Outlet plug Passenger side cylinder head.jpgWater outlet hose fitting 472.jpg 
Second, the water outlet fitting I want to put in.
Rocky Mountain Region Membership Chair & Treasurer
1970 DeVille Convertible Chateau Mauve Firemist
1970 DeVille Convertible Lanai Green Metallic

Dave Shepherd

If you can do it safely, heat the area around the plug, as hot as you feel comfortable with, then get right on it.

CadillacFanBob

Another possibility is Snap-On, 36 inch breaker bar 1/2" drive # SN36

Bob
Frankfort, Illinois

"Cadillac Kid" Greg Surfas 15364

I take exception to that  "ancient"
Comment. I have one of those I needed to work on my Honda Super Hawk in 1965. They are actually still available.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

35-709

I somehow ended up with two of those in my toolbox, comes in handy every so often.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

signart

Looks like you could at least get a small torch with a pencil flame in there. If you don't have a torch, a mapp gas torch will do it. With some care, you won't hurt anything with the heat on the outside of the pipe plug. Try enough heat to get it the first time.
Art D. Woody

fishnjim

It's probably NPT so that's tapered, so it's wedged in there and no one put pipe dope on it when it was installed.   It's now "rust welded" at the thread.  Penetrant has no place to penetrate.
My suggestion is to pull the head.  Take it to a machine shop and let them  drill out the plug and retap the threads and put the hose barb on.   

Your mechanical advantage is lost with an allen type plug on a tapered thread.  They usually have a protruding square head and you put a pipe wrench on them and then you can use a big pipe wrench or wrench with a cheater(pipe extension).  A 1/2" may twist off before the 1 1/4 budges.
I had a antique well pump (cast) come in, a friend wanted me to restore.  We never did get the threads apart, and heat eventually melted the cast.  It'll burn if you get it too hot, because of the high carbon content.  So if you heat cast, you can warp or crack the head. 
 

The Tassie Devil(le)

#11
I agree with the suggestion from Jim, "My suggestion is to pull the head.  Take it to a machine shop and let them  drill out the plug and retap the threads and put the hose barb on."

Trying to do it cold, or even with trying to heat the cylinder head with any flame is fraught with disaster, as there is very little room to swing a long bar, without removing the hood.

I tried to remove a similar fitting with a breaker bar and an extension, and succeeded in snapping the male fitting from the bar.   This was the same breaker bar that I had successfully used many times with a 2 1/2 foot tubular extender that I made.

The problem with breakage under pressure, is that when the snap occurs, one isn't prepared for the continued movement of the broken handle.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Scott Nellis

   I work in the heavy equipment field and have dealt with removal of stubborn plugs in awkward places on many occasions. All suggestions I have read are excellent, but as mentioned you have to break the bond of rust before that plug is coming out. The 1/2" plug socket with a long Johnson bar and possibly a pipe slid over the end of the Johnson bar for more leverage are obviously the appropriate tools needed. To break the rust bond you need to put a small heating tip on an oxy/acetylene torch and carefully heat the plug itself until it gets very hot. Have a spray bottle with cold water ready to zap the plug with water when you are satisfied that you have heated the plug sufficiently. You have a perfect target in this situation by spraying into the female socket well. The idea here is that you expand the plug by heating it, then you shrink the plug by cooling it. This process should break the rust bond and you should be able to remove the plug with far less effort. Patience and accuracy with the torch tip as well as the water stream are important. If you have a narrow stream of water you can try to only cool the plug and the head will remain warm to further help the cause of heat differential between the two components. If it doesn't work the first time, try a few more times. This process will be far less effort than removing the head. Keep in mind that cylinder heads are designed to get hot. By heating the plug itself I can't see you doing any damage to the head. It is important to get the plug very hot or the process won't work, that is why I suggest using oxy/acetylene instead of propane. That would be like bringing a knife to a gunfight. You have to scare the hell out of that plug.
1957 Eureka Hearse
1965 Miller-Meteor Hearse
1968 Miller-Meteor Hearse
1968 Fleetwood Brougham
1970 Superior Hearse

dochawk

Quote from: "Cadillac Kid" Greg Surfas 15364 on September 24, 2022, 05:59:16 PMI take exception to that  "ancient"
Comment. I have one of those I needed to work on my Honda Super Hawk in 1965. They are actually still available.


it's not that the *type* of tool is ancient; it's this particular toolbox and contents.

It was my grandfather's, and I'd really be surprised if it's as late the 50s. 

My father is in his 80s, snd I think this box and contents is older than he is . . . I'd believe 30s, but maybe 40s.

Just the *weight* of the box itself . . . and there sure aren't any *metric* bits here!

meeting that tool was a "where have you been all my life?" moment . . .

assuming I get back home in the next few days, I'll post pictures.

1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)