Bummer!
Builds The Architect's '77 FJ40
- Thread starter GA Architect
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Doesn't Toyota offer a parts warranty? You will have to strip paint and solder.
middlecalf
SILVER Star
A bit of a guess but from my experience that sort of seam failure is a result of the radiator fatiguing from flex. So maybe the mounting is too stiff (lack of rubber mount isolation allows frame/support flex to get transmitted to radiator) or not enough bracing on the support (so again that flexing gets transmitted to the radiator), or both. I struggled with two aluminum radiator replacements as those have less tolerance for flex than copper ones.
GA Architect
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- Thread starter
- #1,784
Yep, I figured it could possibly be fatigue from flex, when I replaced it last year. Thus I replaced all items of the OEM set up with all the rubber bushings. Maybe I'll double up the rubber bushings....I ponder this for a bit before I replace it again.
I’m sure you’ll research extensively, then execute an innovative and enviable solution..... At which point, all of Mudd as well as Toyota’s engineering division will go:
“Damn, why didn’t I think of that!”
“Damn, why didn’t I think of that!”
merbesfield
SILVER Star
Sims Radiator in Chamblee can fix it.
GA Architect
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- #1,787
What was your fix?
The radiator resides in the support, which is bolted to the frame (+/-) below in two spots with nylon pads as spacers. The support also uses two bracing rods connected to the frame with rubber bushings at the support for movement. Which of those locations would some additional movement be needed?
I'd do all of them. Some soft poly bushings and pads would probably help.
Maybe a silly question but is the support true? If it is warped or twisted out of plane that would put a stress into the unit when you tighten it down and all the isolating in the world wouldnt solve the issue. Given you have isolated it and this has happened twice I would check the U.
Something else to consider and that I have dealt with first hand is stray current flowing through the radiator from electrical components. Usually the radiator acting as a ground. The electrolysis causes oxidation and eventually a leak. A good test would be to isolate the radiator from its mounts and conduct a current test via multimeter from rad mounting point to ground, anything more than a few millivolts is cause for concern.
Damn....the knowledge available here is almost freaky.
The way a 40 is built, at least my 77, the radiator pretty much can't be electrically isolated. It's bolted into the u-shaped frame with bolts holding it in at the bottom (albeit over little pads). In any case, that u-shaped frame isn't intended to be electrically isolated, it provides the ground connection for the horns to work.
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GA Architect
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- #1,793
Dang, didn't cross my mind about the "U support bracket" possibly being untrue. It is very possible that could be the case, as it was modified to install the AC condenser.
Did you modify your bracing rods at all when you installed your AC? I did. And I've wondered if that has contributed to the little weeping I'm getting at the top of my rad... not enough support and flexing accordingly. My weeping/crystallization has been pretty consistently minor. Enough that I keep it wiped up now and then and it's never been enough to drip or get blown around by the fan.
GA Architect
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- Thread starter
- #1,795
I did modify the support rods. However, I trued those up by removing the welded stop washer and adding additional threads. Thus I'm able to give 100% adjustability to the U support & rods. I'll go back and check all pieces for trueness and mobility before I button-up & refill the new radiator.
I think the support bracket would have to be quite a bit untrue to affect the radiator... and if it was that bad it'd be similarly harmful to your condenser (if not more so since the condenser is aluminum).
I'd suspect too much flex or too much rigidity would be the answer...
Also, I've chalked it up to the use of the AC in summer. Honestly, we are putting these OEM radiators through the paces when we run AC condensers in front of them. That's partially why I moved my condenser out from the front of the truck. I've installed AC's in 4 FJ40's now... and all of them ended up with a weep somewhere that really only manifests when the AC is used in the heat of summer. Granted, the summers I've experience were in Abu Dhabi and now Phoenix... pretty brutal.
I knew I remembered you doing something to them... tried to find the post but gave up. We need a table-of-contents for your build thread...
Indeed, but in the stock configuration there isn't much if any stray current looking for a path to ground. The OEM electrical systems are simple. Add in an electric fuel pump, EFI, Lights, winch, etc. and you've got some serious electron movement to deal with.
Current goes where it's demanded. IF he was grounding his fuel pump, EFI, lights, winch, etc. to the radiator I'd agree their could be a problem.
The radiator, radiator support, and for that matter the entire engine block are all part of the vehicle's ground path. If you put a multimeter on the radiator or support to check voltage you ought to see a value pretty close to battery voltage (positive lead on battery positive, negative lead touching exposed metal on the rad or support). Alternatively, checking resistance between the battery's negative lead and exposed metal on the rad or support should give you a nice low resistance level. Both of these must be true for the horns to work.
Did you mean milliamps here, not millivolts?
If so I may understand what you're getting at... I think.
