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MG MGB Technical - Radiator expansion tank outlet

Hi,
The outlet from my radiator header tank for the expansion tank can twist in the header tank and consequently is leaking when the engine warms up. I haven't taken the hose off yet, it is tight and I do not want to force it or cut it off just yet. Therefore, my question, is the outlet plastic or brass? Is it brazed in or is it fitted some other way?

I guess what I am really asking is, is there an easy fix/seal it back up, or am I going to have to remove the radiator, cut off the hose and get the outlet brazed back up again? Any thoughts or information would be very welcome. I hope to have it back on the road by Friday for an MOT booking!

Many thanks,
David
David JM

It's easily brazed but you will have to remove the rad first - four bolts.
R Walker

Thank you,

Yes, I am very familiar with the 4 bolts. I have just had the rad out to replace fan motors. So the outlet is brass then? It is strange the way it can spin around, almost like a push in fitting.
David JM

David,

I think the nipple might be soldered in rather than brazed (maybe this is a terminology difference between the UK and USA). I had to solder mine back in on the expansion tank, and the tank was brass. So, it is a bit tough to braze thin brass since the melt temp is about the same as the brazing rod. The lower melt temp of solder makes it easier. I would think it might be possible to do it with the rad in place if you lower the coolant level, though it's not much trouble to remove the rad and it could allow a more favorable working position.

Charley
C R Huff

Hi David,

I would imagine that brazing a brass radiator tank would be disastrous, as the brazing rod is also brass, which means that to melt the rod the tank would melt as well.

Soft soldering would be much safer, and can be done with a heavy duty soldering iron.

Herb
Herb Adler

Thank you Charley and Herb, yes I realised not long after I posted the messages that I meant solder! It is certainly easier than brazing anyway. Thanks for the tips.

Btw, I am still a little puzzled by the way it turns without pulling out, I guess there must be a little bit of solder holding it in. The damage was done originally trying to remove a tight hose. A lesson for us all...

David
David JM

David,

I think the tube may be expanded on the inside of the rad tank to prevent it from coming all the way out if the solder fails.

Charley
C R Huff

Remove the hose, clean the pipe and header tank and seal with two-pack Epoxy Putty. 'Milliput' in UK.
Geoff F.
Geoff Farthing

All done, a jar of flux, a stick of solder and a blow torch. A good solid joint with a nice fillet of solder all around, now just waiting for the paint to dry!

Btw, I got the fitting pretty loose, but it would not come out. I think Charley is right, it is probably expanded on the inside before the tank is soldered to the core.

Thank you for all the input guys. Just to set the record straight, mine actually has 6 bolts, 3 on each side.

Cheers, David
David JM

This thread was discussed between 14/03/2011 and 15/03/2011

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