Map bronze solder a car radiator?

[Sebculb]

Hola everybody,

Anyone got any insight as to this would work (well)? My buddy that does refrigeration work was showing me how to braze or solder copper tubing with bronze stick and a map torch. My first time playing with it. Seems pretty straightforward, at least for the easy situations, just like welding.

So would this work to plug up a hole in the top part of the radiator on my 87 Toyota 4runner? It's right next to the cap and squirts water so it's easy to find and id prefer to not have to pay a professional to do it. Epoxy didn't work. I think it's made out of steel, there's rust in the water at least.

Thanks for any advice,

Sebastian

 

[Stimw]

The trick to soldering is to CLEAN very well.

 

[flyerdan]

The radiator should be brass, the leak is on the top tank, by the filler neck, correct? Since it's probably painted black, scrub the paint off with some scotchbrite and see if it's the brass yellow. You could solder it with plumbing solder as that requires less heat than brazing, and less likelyhood of the hole getting bigger as you chase it.
If the hole is above the cores, make sure that there is coolant above the seam where the tank meets the core to avoid heat transfer melting that solder joint.
The rusty coolant is due to the cast iron engine block, radiators traditionally are brass, or aluminum with plastic tanks; that vintage of Toyota should still be brass.

 

[Sebculb]

Thanks! Brass, eh? Does That mean bronze solder is NOT recommended, in that it melts too hot and will poke holes? Would plumbing solder be the way to do it "properly"?

Thanks again

 

[yomax4]

Be very careful on the solder you choose for the repair. The neck is probably soldered on with something like 50/50. If you get a solder that has a liquidus higher than the neck solder you will have things falling apart while you try to fix the hole. That being said, How large is the hole or is it a crack? There are several sure fire fixes. Plumbing solder will work with the proper flux but try to get something that melts around 430 or less. You need to find out if it' Steel ( doubt it ) Brass or Aluminum. None of the Plumbing solders will work on aluminum but there are some Aluminum solders out there. We can get into that when we know for sure what the base metal is.

 

[TractorGuy]

Buy a new radiator. If it has one hole it will develop another.

 

[Sebculb]

Thanks​ everyone! Pretty sure it's not aluminum, I'll check with a magnet when I get home if it's steel or brass

 

[ultrarunner]

I used plumbers solder to fix a radiator on a Model A in 1975... still holding up fine.

I think bronze or brazing like used for HVAC would be problematic since it requires more heat... just my opinion.

 

[TractorGuy]

I used plumbers solder to fix a radiator on a Model A in 1975... still holding up fine.

I think bronze or brazing like used for HVAC would be problematic since it requires more heat... just my opinion.

I agree that brazing would be too hot. I'm pretty sure the flues are soft soldered to the header. Same with the tank.

We had a whole building generator develop a leak on the radiator tank. Repair guys had it soldered instead of replacing it. Tank cracked two inches from the repair and ran all the coolant out. Overheat safety shutdown failed and fried the V8 engine. I don't know how much the engine rebuild was but it didn't last and the whole generator had to be replaced. Lost years of research samples because someone saved $400. Car radiators are even cheaper.

 

[ultrarunner]

Not a lot of old fashioned radiator shops around here anymore... there were a few artists that could build what ever you needed.

A friends was doing engine swaps and always needed a custom radiator... no problem.

I towed a lot with my 318 Valiant... in the mountains the temp would push the needle... mentioned it to the owner of the shop and he said lets build one with a truck core... never had another issue and I have owned this vehicle 40 years now...

Some of the classic cars can have radiators well over a thousand dollars...

 

[dragoneggs]

I say try to fix it first... sand it down locally and get it clean. If brass you will know by the color. Can't hurt to try typical plumber or general metal acid core solder. Cheap fix to try on your own. If it doesn't work you can take a gamble on a radiator at a junk yard but you learned along the way.

 

[dfkrug]

I thought Toyota trucks already went to aluminum/plastic radiators by the mid-80s. Maybe that is just in the US. New replacements are under $100.

I love the older brass radiators since they are easy to fix. My '80 Toyota PU had a brass radiator. I have re-soldered the top tank and hose connections on several rads. If one part gets a leak, it is easy enough to re-solder the whole periphery of the tank. I always used lead/tin plumber's solder and Kester paste flux with propane torch.

The aluminum rad cores can be repaired, but it is not nearly as easy. The plastic tanks, fugeddaboutit.

 

[Sebculb]

Thanks ultrarunner and JD 855, that was the information I was looking for, that brazing isn't the right thing. I'll get some plumbers solder and start experimenting tomorrow. Hopefully won't screw anything up worse, but the truth is it can't get much worse than it is.

So bronze Rod's the wrong stuff, does anyone know if a map torch would be too hot also? Is propane or butane better? Was reading elsewhere that more heat is good to a point because it heats up the area of interest fast before nearby joints get affected.

 

[Sebculb]

Thanks Dragon eggs and Dfkrug! I will try to fix it tomorrow good to know the propane works, would a mapp torch work better by any chance? Cuz my buddy's​ is at work right now, and​ I'd have to buy the propane torch. Should probably have one anyway, but I dunno if tomorrow's​the day

 

[dfkrug]

I will try to fix it tomorrow good to know the propane works, would a mapp torch work better by any chance? Cuz my buddy's​ is at work right now, and​ I'd have to buy the propane torch.

MAPP is fine, if you have a brass rad. Be sure the top is not plastic.

 

[dragoneggs]

MAPP is fine, if you have a brass rad. Be sure the top is not plastic.

I'm no expert but MAPP or propane is fine. It's about the amount of heat you apply. That is in your control. Watch a couple youtube vids on 'soldering a radiator'. There are lots of them.

 

[Sebculb]

Thanks! I'll see if I get to it today and post up how it works

 

[Sebculb]

Sooo, my wife and my dad heard I was going to start experimenting on the car with a blowtorch and got a lot more proactive about​ dropping me off at work and taking it to the radiator shop. So I guess some good came out of my asking questions cuz the things fixed now, for better or worse.

So I guess I'm sticking to burning the 6013 for now, all day every day. Thanks again for all the advice! I'm sure I'll apply it sometime.

 

[Jeepnford]

A friend of mine has been fixing radiators for years. He always uses silver bearing solder. I have seen it at some of the box stores near the welding wire/rods.

 

[fried1765]

Thanks Dragon eggs and Dfkrug! I will try to fix it tomorrow good to know the propane works, would a mapp torch work better by any chance? Cuz my buddy's​ is at work right now, and​ I'd have to buy the propane torch. Should probably have one anyway, but I dunno if tomorrow's​the day

MAPP will certainly work, but you need to be very careful with the amount of heat you apply, or you will melt a spot on your radiator.
Propane (blue tank) really is the best option, with 50/50 solder. Be sure to clean the area thoroughly, and use soldering paste.