Rust under rear bumper

Hey everyone, just bought a 2005 4Runner, maybe was slightly impulsive in the purchase and didn’t give the frame a good enough look over. Anyway, while knocking around with a hammer under the rear bumper I discovered this.. anyone else have this? How structurally significant is this spot? I’ve read enough posts on here to know my options for treating the area, just hoping for some opinions.. thanks!

 

I'd say fairly crucial. The body mount is farther up, but your camera angle is right on the anchor/tow point mount, as well as the general area where your tow hitch connects to the frame. Dont need to risk that whole area coming apart due to stress when towing. Lastly we have boxed frame SUVs here... the box needs to remain a box and not rust away to be effective

 

Pretty common for the end caps to rust out. Mine is slightly more cancerous than that, so I'm going to probably cut it in front of the body mount, remake the body mounts, and fab a rear crossmember and bumper to get rid of all the swiss cheese metal. The inside corners of that rear crossmember are sorta gusseted to the side frame rails, so its not like the whole rear will fall apart.

If I were you, I'd remove the cover, cut off anything bad looking, and weld in new stuff

I'd also avoid towing with it.

 

Crusty, but definitely fixable! Weld in a new section, no big deal. I might try to get a frame section from a low mileage wreck to repair it with, but these pieces are easy to make. Even if you can’t weld yourself, this should be no big deal for a pro. Probably a good idea to descale the rest of the frame with a needle gun, and paint it with por15 semi gloss black and then fluid film the whole chassis.
Let us know how it turns out! I think Toyota’s get a bad rap for rusty frames. Ok, they do rust prematurely if neglected, but anything close to 1/2 assed maintenance will keep a Toyota underbody going just as long as the rest of the vehicle.

 

Thank you guys for the help and reassurance. The rest of the frame seems alright *fingers crossed* besides the front radiator support cross member could probably use a weld. I’m definitely going to get everything cleaned up and coated (not sure whether I’ll do it myself or not yet). All that aside, I’m so happy to finally have a 4Runner, and be part of such a helpful community. Here she is..

 

That 4 Runner looks great! I find with dirty jobs like coating a frame that it’s hard to find help that cares as much as you do! Maybe, though, good luck!

 

I have a 2005 4runner with 170,000 miles. I've read about others rust problems, but my bottom is virtually rust-free underneath, and has zero rust on the painted body. The front frame "bar" right behind the radiator had some superficial rust so I brushed it off and sprayed it with corrosion X a few years ago, and it turned the rust black and isn't an issue anymore?

4runner is one block from the ocean in the sunny tax-free Bahamas. I don't see rust as ever being a problem with my 4runner, but I've read of rust complaints by others. Could it have to do with the factory and materials used when it was newly built? I've owned mine since new from the dealer.

I've replaced a few starters, but the current one came with a lifetime warranty and I called the manufacturer and they told me if it ever fails they will send me another one. Amazon doesn't offer this lifetime (starter) warranty anymore. Is that strange?

My starters were all failing after 4 years(including the OEM). The current starter is 4-1/2 years old, and still cranks it up. I wonder still!

$112 DB Electrical 410-52161 Starter Compatible With/Replacement For Toyota Tacoma & Tundra 4.0L 4.0 05-09 2005-2009 & 4Runner 03-09 2003-2009 FJ Cruiser 07 08 09

Amazon.com: DB Electrical SND0491 Starter Compatible With/Replacement For Toyota Tacoma & Tundra 4.0L 2005 2006 2007 2008 2009 & 4Runner 2003 2004 2005 2006 2007 2008 2009 FJ Cruiser 2007 2008 2009: Automotive

I keep a backup new start in the garage just in case. It costs $90 at Amazon. The local dealer that sold me the 4runner new once wanted $900 to order a new starter from Japan. I live in the Bahamas. I thought that was outrageous since I bought the car from them new. Next time I'll buy a Ford.

 

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@captsolo - that’s interesting obviously the Bahamas are different than the Northeastern US and Canada. There are so many factors. It’s great your 4 Runner will last forever! I’m envious!
As for starters, that’s pretty strange. There’s no reason why you should ever need a replacement starter unless something is amiss in the electrical system or your vehicle starts hard and you’re winding it over too long. Modern starters are quite fragile, and will only handle relatively short bursts. If your engine doesn’t start for any reason, and you keep winding it over you risk burning it out. Modern fuel injected engines in proper tune should start right away.

 

In regards to timeline, how urgently do you think I should do this, obviously sometime soon, and definitely before the winter. But is it like a do it this week kind of thing, or do I have a little time to plan accordingly and get everything set up?

 

My engine starts the first turn - every time. Like I said, I get three times as many starts on my 4runner as a car in Miami because the longest trips are 2 miles. That's why they fail IMO (two million starts every 4 years / manufacturing quality not good enough for the Bahamas.) The current starter has a lifetime warranty (free replacement) and is 4-1/2 years in service.

When the starters failed you turned the key and you got nothing. It was the starter's solenoid's failing. There was never any trouble with the 4runner not wanting to start right away.

I think the solenoids were burning out. There's also excessive heat here in Nassau.

 

Everyone has their own strategy and work style, gelpen3, so I wouldn’t attempt to be prescriptive about the time it will take you. What’s that old saying - slow, cheap and good - you can only have two without the other, pick out any two. For myself, I’m slow as molasses. I had a Jeep up on Jack stands doing similar work on it for 5 months this past winter during Covid. It was relaxing, because there was no where to go anyway, so I just took my time. But probably your vehicle is a daily driver, so it will need to be done in a timely way. Break the work down into manageable sections, factor in some contingency time for the unforeseen, and go for it. Good luck! Let us know how it turns out.

 

Yeah, it’s not the number of starts, it’s the duration that fries starters. I don’t think the heat in Nassau is that excessive to cause premature failure of a starter. You have something else going on, and it will take a good mechanic/automotive electrician to figure it out. It’s not the starters or the Bahamas weather, that’s for sure.

 

It's the failing solenoids on the starters. A company has sold me a lifetime guarantee starter/solonoid that has been in their 4-1/2 years so far. Will it last another 10 years?

I do think it's the heat (rain getting to starter/solonoid which is at bottom of the engine); the excessive number of starts I go through as compared to a car with 1/3rd as many starts in the USA.

 

@captsolo You may be right, and if you are, all the other Toyota’s like yours in the Bahamas will be experiencing similar problems. This should be easy to check out.