Tips/Tricks on Replacing Radiator Push Nipples....

AdmiralYoda

So I finally removed my leaky radiator and plan to split the sections where it is leaking. To split them I will cut four wooden wedges, lie the radiator on its side and put two wedges at the top and two at the bottom. Just keep driving the wedges in until the section splits.

What I don't know yet is how to get the push nipples out once the to sections are split. Chisel and hammer? The radiator is cast iron and probably as old as the house, about 120 years old.

I've thought of buying a used radiator in unknown condition but the asking price is usually $200+ and for the cost of some push nipples ($15-30) I figure its worth a shot.

Jamie Hall

You may find that the leaking nipple is so shot that you can just collapse it, then pull it out.

If you do resort to a chisel, use it to try to collapse the nipple. Be very careful to avoid knicking the seat in the radiator section if you can.

Separating sections.... you can also use the type of expander used in auto repair to loosen ball joints.

AdmiralYoda

Thanks! Here is a newbie question... I assume there are two push nipples right? One at the top and one at the bottom? Or is the top one something else?

Jamie Hall

Two. The one at the top is probably OK, though -- though no harm to getting a spare.

Hap_Hazzard

Don't use a chisel! I pulled mine out with a slide hammer, but it doesn't take much. They're tapered, so they just pop right out.

AdmiralYoda

Thanks again. I'll just gently clean it since its not leaking and just replace the bottom one.

I'll put a little high temp automotive RTV in between the sections and cross my fingers.

Jamie Hall

If you put RTV in there, make sure that it doesn't get on the nipple or its seating surfaces. I've use it, though, that way, as a ring around the outside of the nipple (not touching) and inside of the outer ring cast on the radiator section. Shouldn't need it, but...

AdmiralYoda

Just planning for the worst. I am usually confronted by surprises and am also Captain Overkill at the same time. Just don't want to do this twice.

If the radiator plate surfaces are in good shape I'll leave it alone. I have a feeling its been leaking for a couple decades anyways, so who knows what I'll find.

retiredguy

If you need to clean the mating surfaces use only fine steel wool or crocus cloth and not a wire wheel or wire brush. If you are using new nipples or reusing the old nipples I would use grease on the mating surfaces. To remove a nipple when you can access the opposite side use a drift punch with a flat end and not a chisel or anything with an edge.

AdmiralYoda

Its been almost a year since I posted this thread and am just getting around to fixing the radiator.

Why is it a bad idea to use RTV again? It stands up to high pressure + temperature in the automotive world, just wondering if it would help in this situation.

Jamie Hall

It's not a bad idea, if you really need it. But not on the mating faces of the nipple and its seats. Those are closely machined and, if they are in decent shape, should need no sealant at all. But see my earlier comment -- in some cases creating a ring gasket around the nipple -- but not on it -- may solve problems which are otherwise difficult.

flat_twin

I had success by cleaning the nipples / mating surfaces thoroughly with steel wool and then a smear of gray pipe dope for reassembly.

AdmiralYoda

I plan to take this radiator apart tonight (hopefully). 10 years ago I tried packing the joint with JB Weld to try and seal up the leak from the outside. Actually held up for a couple of years.

I'll post some pictures when I get into it.

The mechanic in me really wants to smear RTV on it and put it back together if the nipples are still good. We'll see, its my house so if I screw it up I can just do it over free of charge!

Hap_Hazzard

I'd try hi-tack copper instead of RTV.

AdmiralYoda

Hap_Hazzard said:

I'd try hi-tack copper instead of RTV.

Like Permatex Ultra Copper or some other thing I'm not familiar with?