rear core freeze plug removal/install with engine in place : MGB & GT Forum : MG Experience Forums : The MG Experience

rear core freeze plug removal/install with engine in place #1
MGB 1976 Mark Turechek Central MA, USA 1976 MG MGB "The Never Ending Project"	Posted: April 10, 2012 08:28PM Registered: 5 years ago Posts: 221

Has anyone removed the rear freeze core plug with the engine in place? I found a lot of threads where the rear blew out and replacement was possible with the Betson Bolt. My rear plug is leaking slightly. I removed and refitted the engine after replacing the clutch last year and I don't have the ability to do this again right now. The engine sat around without antifreeze but a rebuild for about ten years and leaks showed up on 3 of 4 freeze plugs after about 1000 miles - the clutch (and my lack of time and resources) was keeping the car running and road-worthiness. Is it possible to get at the rear plug for removal and replacement with the engine in place?

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Re: rear core freeze plug removal/install with engine in place #2
danc Dan Cramp Menifee, Ca., USA 1971 MG MGB	Posted: April 10, 2012 10:04PM Registered: 8 years ago Posts: 3,102

Very possible. Keep searching.

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Re: rear core freeze plug removal/install with engine in place #3
ClayJ Clay Johnston Mt. Olive, MS, USA 1972 MG MGB	Posted: April 10, 2012 10:09PM Registered: 7 years ago Posts: 7,359

Yes. Some have posted a bolt, washer and nut arrangement thru a existing hole in the back plate to press against the freeze-plug.

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Re: rear core freeze plug removal/install with engine in place #4
mbarjbar Michael Barrera Winchester,California, USA 1967 MG MGB GT 1967 Pontiac GTO 1970 Datsun 240Z ""Nate The Z"" 1971 MG MGB "Gigi"	Posted: April 10, 2012 10:21PM Registered: 7 years ago Posts: 1,104

Removal will be very difficult with engine in place. Try the Betson bolt. It may cause the plug to seal once pressure is applied.

Mike

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Re: rear core freeze plug removal/install with engine in place #5
oily-hands Owen Frankland Stockton on Tees, Cleveland, United Kingdom 1937 MG TA "Numbum" 1971 MG MGB GT "The Bruise" 2002 MG ZR	Posted: April 11, 2012 01:36AM Registered: 3 years ago Posts: 5,179

We have a product over here called 'Plumbers Mate, made by Evo Stick. It will probably be available worldwide but maybe under a different name.

It's a two part product which, when mixed together will seal leaks, even when wet.

It sets hard and lasts like forever. I've used it on two plugs on the TA, initially as a temporary fix which has lasted two years.

Ideal for those hard to remove plugs.

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Re: rear core freeze plug removal/install with engine in place #6
ErnieY Ernie Y Nr Cahors, France 1970 MG MGB 1976 MG MGB GT 1978 MG MGB	Posted: April 11, 2012 02:33AM Registered: 1 year ago Posts: 2,864

I agree getting it out will be the biggest problem but if it's just weeping slightly then you should be able to use the hole on the adapter plate to jack a plate over the whole thing with a piece of thickish gasket material in between for a perfect seal.

I'd certainly try to do something about it though as if it's corroded to the point of leaking then it's possible that it could blow out altogether. Since you do want it out that's not necessarily bad however it's the sort of thing you want to happen under selected and controlled conditions and not when you're 1/2 way into a major road trip !

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Re: rear core freeze plug removal/install with engine in place #7
twigworker Jack Austin Blowing Rock, NC, USA	Posted: April 11, 2012 07:02AM Registered: 7 years ago Posts: 20,754

Just my take on the situation...

I understand that it is possible to deal with this when the engine is in situ but I never have. It just seems to be a way of sidestepping a proper repair.

The Lord knows that it is difficult enough to make sure that a plug being reset on the SIDE of the block is going to be secure and leak free, and trying to do the gymnastics at the back of the engine would be worse.

I suspect that what ever you must do to deal with the situation without removing the engine will be only slightly less that what you will have to go through in yanking the motor and doing the replacement out where you can see what you are doing.

Think of pulling the motor as a sleep aid, and doing the work with the motor in place as an anti-sleep aid. winking smiley

Jack

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Re: rear core freeze plug removal/install with engine in place #8
gooser Drake Myers Danville Va, USA	Posted: April 11, 2012 07:31AM Registered: 5 years ago Posts: 6,928

i've never done it but it seems to me that if you can open a bottle of wine you should be able to do it.

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Re: rear core freeze plug removal/install with engine in place #9
Sinewave T. Keith Vezina Kenner, LA, USA	Posted: April 11, 2012 02:27PM Registered: 7 years ago Posts: 1,218

I had to do the bolt trick on two different engines last year; one was a severe leak. They are both still leak-free. It's practically impossible to remove the plug with the engine in place. IMHO, if you did manage to get it out, you would not be able to seat a new one properly.

T. Keith Vezina
British Motoring Club New Orleans
1976 MGB, 1976 MGB Trailer & 1967 MGB MK. I

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Re: rear core freeze plug removal/install with engine in place #10
ErnieY Ernie Y Nr Cahors, France 1970 MG MGB 1976 MG MGB GT 1978 MG MGB	Posted: April 11, 2012 02:36PM Registered: 1 year ago Posts: 2,864

there seem to be two different types of core plugs used on the B engine, the cup type

and disk

If you have the latter then it may be possible to insert another disk on top of it compressed and then held in place by a Betson bolt arrangement.

Edited 1 time(s). Last edit at 04/11/2012 02:37PM by ErnieY.

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Re: rear core freeze plug removal/install with engine in place #11
dickmoritz Dick Moritz Philly 'burbs, PA, USA	Posted: April 11, 2012 02:39PM Registered: 3 years ago Posts: 7,253

Ernie,

I've never seen a cup-type plug used (properly...) on a B-series engine. Because of the step in the plug hole, a cup-type plug will not go in far enough to seat properly. I've only ever seen convex-type plugs used except, of course, for the bolt-in types currently under discussion. Perhaps you've seen shallow cup-type plugs used with success?

Dick

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Re: rear core freeze plug removal/install with engine in place #12
twigworker Jack Austin Blowing Rock, NC, USA	Posted: April 11, 2012 02:58PM Registered: 7 years ago Posts: 20,754

X2 on Dick.

I have SEEN cup type plug in the side holes, but their raised edges stuck out. The Lord only knows how well they stay or seal.

Again, unless it is an out and out emergency, why not fix the thing right the first time and sleep well from then on?

Jack

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Re: rear core freeze plug removal/install with engine in place #13
Derek70mgb Derek Gale Victoria bc, Canada 1970 MG MGB	Posted: April 11, 2012 03:15PM Registered: 6 years ago Posts: 552

you can remove the plug over the dizzy and tap out the rear pug with a long screwdriver , reached through the water jacket,
then replace the rear plug with the betson bolt proceedure which sets and holds the rear plug using a bolt and large washer.Then replace the plug over the dizzy.

good luck

.

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Re: rear core freeze plug removal/install with engine in place #14
ErnieY Ernie Y Nr Cahors, France 1970 MG MGB 1976 MG MGB GT 1978 MG MGB	Posted: April 11, 2012 03:38PM Registered: 1 year ago Posts: 2,864

In reply to # 2037384 by dickmoritz Perhaps you've seen shallow cup-type plugs used with success?

Define success Dick !

I have seen them on cars in regular use and have no personal knowledge of any failing.

I wouldn't use them though.

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Re: rear core freeze plug removal/install with engine in place #15
MGB 1976 Mark Turechek Central MA, USA 1976 MG MGB "The Never Ending Project"	Posted: April 12, 2012 12:42PM Registered: 5 years ago Posts: 221

Here's what I'm dealing with. I think the rear is about the same, but a bit less leakage. I can't get a good photo of the rear. The front is leaking, too. Is this a ticking time bomb?

Edited 1 time(s). Last edit at 04/12/2012 01:54PM by MGB 1976.

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Re: rear core freeze plug removal/install with engine in place #16
MGB 1976 Mark Turechek Central MA, USA 1976 MG MGB "The Never Ending Project"	Posted: April 12, 2012 01:48PM Registered: 5 years ago Posts: 221

The center plug seems to be OK but because the others are leaking I think it is a candidate for replacement. Is it possible they were not seated properly with the original installation?

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Re: rear core freeze plug removal/install with engine in place #17
ErnieY Ernie Y Nr Cahors, France 1970 MG MGB 1976 MG MGB GT 1978 MG MGB	Posted: April 12, 2012 02:43PM Registered: 1 year ago Posts: 2,864

That rear one looks very insecure to me but look on the bright side, if it does come out the water will instantly flood the distributor stopping you dead before you run any chance of overheating the engine cool smiley

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Re: rear core freeze plug removal/install with engine in place #18
MGB 1976 Mark Turechek Central MA, USA 1976 MG MGB "The Never Ending Project"	Posted: April 12, 2012 03:46PM Registered: 5 years ago Posts: 221

I guess I should fix it soon rather than running the risk of ruining my brand new Jeff Schlemmer 25D.

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Re: rear core freeze plug removal/install with engine in place #19
ClayJ Clay Johnston Mt. Olive, MS, USA 1972 MG MGB	Posted: April 12, 2012 04:13PM Registered: 7 years ago Posts: 7,359

So, you have three of 5 leaking? Wonder if the incorrect size was used.

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Re: rear core freeze plug removal/install with engine in place #20
MGB 1976 Mark Turechek Central MA, USA 1976 MG MGB "The Never Ending Project"	Posted: April 12, 2012 04:29PM Registered: 5 years ago Posts: 221

I can't remember if I put them in or if they were already in the block when I rebuilt the engine with my Dad in 1987. Unfortunately, he's not here to ask. I have a faint memory of assisting with the installation. Unfortunately, the engine sat idle for many years. Antifreeze wasn't always in the block, which could have lead to them rusting out. The leaking showed up soon after getting her street legal in August last year and then putting about 1000 miles on the car. I had the system pressure tested and the technician pointed out the leaks at the freeze plugs (I told them I was concerned about them when I brought the car to the Firestone shop last month). I won't have access to a lift, hoist or garage or wife's permission to pull the engine until after this summer.

Edited 1 time(s). Last edit at 04/12/2012 04:32PM by MGB 1976.

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