Anyone brazed a brass radiator before?

[Bushman5]

1990 Mazda B2200, over 1, 373, 345 plus KM’s on it. 75% highway, 15% off-road/FSR, 10% city. Has never had short trips under 50 Km . Redline 5W40 full synthetic or LiquiMoly synthetic all it’s life, coolant change every year, etc etc

I got the original brass / aluminum radiator, the top brass cap is soldered / brazed to the core. The mounting brackets on the top left have come off and I need to braze / solder it back on.

Is this easy to do? Propane torch and flux / solder? Or do I need heavier welding gear ?


Thanks in advance

 

[71Chevyguy]

I hate to say it but I have done this with a torch and solder before. I was impressed that it worked, not sure if I would recommend it as a "fix" though.

 

[oldcodger]

If it was attached by soldering I would use that. It is not hard. A propane torch and solder.

 

[bullwinkle]

Acid flux, 50/50 lead solder, roughen up the parts first to improve solder adhesion, be sure to use soap & water afterwards to get all the acid off. A coat of black engine paint over the repair helps stop corrosion of the bare metal. Done it lots of times in the old days, along with pinching bad tubes & soldering them shut. Not many brass ones left anymore.

 

[JimPghPA]

A good radiator shop would be the best way to go with this. It probably does require evaluation of: whether it is clogged? if clogged can it be flushed? if not clogged can it be fixed?

Good radiator shops are not as common as they use to be, so finding one may or may not be possible.

 

[Bushman5]

A good radiator shop would be the best way to go with this. It probably does require evaluation of: whether it is clogged? if clogged can it be flushed? if not clogged can it be fixed?

Good radiator shops are not as common as they use to be, so finding one may or may not be possible.

Radiator internals are clean as new. I take the rad off every couple of years and soak in white vinegar for a few days, then hot flush it. It’s just the upper mounting bracket that’s worked its way loose. It was brazed/soldered in from the factory.

 

[Bushman5]

Thanks everyone! Didn’t expect this much support so fast !

 

[ripcord]

Flux is the key. Brush or sand the contact area and apply flux (get the type that plumbers use) to the contact surfaces. Hold the parts together and heat with a propane torch until the solder will wick in between the surfaces. Use enough solder so that it's coming out all the way around.

 

[dishdude]

Radiators still had brass in 1990?

 

[Bushman5]

Radiators still had brass in 1990?

The Canadian Mazda 1990 B2200’s did

I’m still on the original rad

I’ll get pictures in the AM when I’m at the truck yard

 

[Timmastertech]

Back when we used to solder radiators and gas tanks on a regular basis we used a 200 watt soldering iron rather than a torch. Much more controllable

 

[SC Maintenance]

I watched my dad do it. My dad was good at such things. Its really easy to over-heat the tubes he told me - like heat the brass or tank too much and other bad things happened. He used low heat, kept it on for a very, very short time, would plunge in the solder and remove the heat immediately, and often had to re-do it, often multiple times.

The only suggestion I have is go slow and plan for many redo's. Better to start with too little heat and move up than overheat.

 

[shortyb]

I watched my dad do it. My dad was good at such things. Its really easy to over-heat the tubes he told me - like heat the brass or tank too much and other bad things happened. He used low heat, kept it on for a very, very short time, would plunge in the solder and remove the heat immediately, and often had to re-do it, often multiple times.

The only suggestion I have is go slow and plan for many redo's. Better to start with too little heat and move up than overheat.

All of this. That tank is probably thin as heck too, so overheating can be not good. As stated, clean/sand contact areas, acid flux and 50/50 lead/tin with lower melting point ~400F. You can use a torch (smaller one), but for something like that an adjustable high watt electric might be better/easier for a novice.

 

[bullwinkle]

Radiators still had brass in 1990?

Seen GMT400 6.2 diesel ones in both brass & aluminum, depending on the age. My '89 F-450 still has the original brass radiator in it, although I have a Spectra all AL one for it in the attic.

 

[Donald]

This kind of thing was common for radiator shops to do.

 

[MasterSolenoid]

If possible, practice .... practice .... practice.
When I do a small plumbing job at home (soldering copper pipes),
I'm always surprised at how easy it is .... when I get to the 'last' joint.

 

[vwmaniaman]

I have soldered on radiators before used a thin point propane torch and good lead solder. Be careful with the heat and don't stay on one spot too long or it will oxidize and not stick. Does that truck have the 2.3L and the timing belt?

 

[Bushman5]

I have soldered on radiators before used a thin point propane torch and good lead solder. Be careful with the heat and don't stay on one spot too long or it will oxidize and not stick. Does that truck have the 2.3L and the timing belt?

2.2L iron block, custom heavy duty crankshaft, forged iron con rods, custom milled pistons, aluminum cylinder head, hydraulic lifters, high grind cam, Pacesetter header, Weber 32/36 2 barrel carb, and yes, a timing belt. 15 min swap

 

[vwmaniaman]

Sounds like you have it setup right.

 

[Chris142]

No! I worked at a radiator shop for 20 years. Never braze one. You can solder it with 60/40 solder or 15% silver solder only. Brazing one is too hot.