Crossmember rusted out -- yikes!!!

T

thumper300zx

Member
Location
Utah
Car
2003 FX35
I had to get under the car to replace the rear camber and toe adjusted bolts. You have to remove the center-mount bolts for clearance on those. You also have to remove a couple plastic splash panels to to get to the ASB bolts. While removing the splash panel bolts, they pretty much all busted off (the bottom side of the entire car is a rusted mess). But worse, removing the rear-most 10mm bolts, a very large portion of a crossmember that sits between the gas tank and the rear suspension completely broke away -- the bottom side of that whole crossmember is rusted out, very crumbly and easy to break apart. I'm not even sure which part it is from a diagram, but I'm assuming it would be quite a PITA to replace. Anyone have experience with this kind of stuff on an FX35 (2003)? Nightmare...

I was thinking maybe it was:
[TABLE="width: 100%"]
[TR]
[TD="class: redText, colspan: 2"]74510 - BOARD ASSYREAR FLOOR [/TD]
[/TR]
[TR]
[TD="class: part, colspan: 2"] Part Number: 74510-CG000 [/TD]
[/TR]
[/TABLE]

http://timdahleinfinitimurrayparts....01&partnumber=Part+Number&description=Keyword

---------- Post added at 04:08 PM ---------- Previous post was at 03:42 PM ----------

Here are some pictures...as I said, it's between the rear suspension/axle and gas tank. I'm thinking it's probably there for protection more than anything. Doesn't seem horribly important structurally. You tell me :)

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honestly where was this car stored? In the f*cking ocean? that's just crazy, i have never seen that before on a car that's not 30+ years old
 
Wow that's insane!! But there's an easy explanation for this..where is this car stored? Is it anywhere near grass?

Nevermind, he's in Utah and they get tons of snow. With that being said, the roads must get salted pretty heavily. That's why its this way. Was the car ever rust proofed? If not...you better start now or you'll be replacing sub assemblies...like that one that's eaten already.

Nissan/Infiniti is pretty known for rusting fast, they don't secure the undercarriage all that well.
 
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I can't wait to get away from snow and salted roads here in Toronto, just waiting on a few things to setup in Cali and i'm outta here!! then I'll get to hang with cool guys like Dracula ;)
 
I believe the car was in *gulp* Cleveland before it came to Utah -- Utah might've been an upgrade. I have a 2004 Nissan Quest and it's not nearly this bad. It's been in Utah for 150,000 miles (bought new) -- this FXalso has 150K. I think it's been in Utah maybe 3 or 4 years.

Every 'under the car' job I've done so far has been absolutely hell because of rusted on bolts. I feel a little stupid for not looking under the car better when I bought it -- the outside and interior were just so near perfect I didn't think it would be an issue. Luckily it looks like it's a few specific parts and the bolts that are really bad, but not everything.

Anyway -- if anyone can confirm the part, let me know.
 
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Ah, it hit me now, I remember this part..mine was just starting to rust on some of the edges. This is a multi use piece that protects the fuel tank, adds some strength to the floor and I think there were other uses for it. I wish they had this part undercoated from factory, would at least keep it from rusting to that degree.

I would still try to rust proof it so the rust doesn't continue into the flooring.
 
Ok -- yeah, it doesn't seem overly critical -- I don't know what rust proofing will do at this point. But I'll try to get under there again and chip away until it's solid. It looks like a real PITA to replace. It looks like it just gets the brunt of anything flying up from the road toward the back -- should've used aluminum. Also, much like you said -- it has some kinda 'rough' edges, corners, etc, for stuff to really gather up. It curves up over the exhaust and driveshaft, then comes back down and connects to each side of the car. I just have to hope, assuming I do replace it at some point, that the bolts and other parts it mounts to aren't rotting away.
 
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Sometimes I question the things Infiniti does, at least they could coat it with something to prevent rusting. I would chip away as much as you can without killing yourself, watch your eyes, rusted debris is pretty bad, and wear a mask, it does get airborn too. Then just spray it with rustproofing oil, it will stop it and prevent it from continuing. That way you can buy some time. The oil will wash out slowly, but its better than nothing. When I bought my 2nd gen, that's the first thing I did was climb under the car and check the undercarriage.. The differential and exhaust is the only two things rusting on my car..and its leaving rust spots on my garage floor..can't wait to get an Invidia exhaust and I'll have to paint the differential
 
Yeah, Infiniti's do seem to corrode fast. Mine was from NY but it was only there for less than 2 years and 12K before I bought it. Rust wasn't too bad visually, but every bolt was corroded or frozen. Exhaust was rusty and had to be cut off and I had to replace a swaybar end link because the bolt was stuck on. And there were rust spots on the engine cradle which is somewhat weird since it's mostly covered by the splash shields.
 
What I did when I got my ride was I had it washed clean underneath, dropped all the liners, shield, skirts and undercoated the entire underneath. So my bottom end is secured. That was last year, and now this year i'm going to be checking to see if I missed anything then rustproofing it. Rustproof sticks really well to undercoating and dust then stick really well to the rustproofing oil.What it does it creates this paste that is hard to come off, so you'll have a nice barrier from that level.
 
SCY7H3 said:
What I did when I got my ride was I had it washed clean underneath, dropped all the liners, shield, skirts and undercoated the entire underneath. So my bottom end is secured. That was last year, and now this year i'm going to be checking to see if I missed anything then rustproofing it. Rustproof sticks really well to undercoating and dust then stick really well to the rustproofing oil.What it does it creates this paste that is hard to come off, so you'll have a nice barrier from that level.
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you guys in Toronto get that salty air and lakes and they put salt on the roads. We don't have that problem in Alberta, air is dry, no salt water anywhere close to us, and they don't put salt on the roads, only sand (which destroys the paint from all the rocks flying everywhere).
I know a few people trying to sell their Ontario cars in Alberta, and everyone is running away, no one wants to touch them
 
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