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Frame Rot by gregr75
Started on: 08-16-2022 09:19 AM
Replies: 20 (679 views)
Last post by: zkhennings on 08-24-2022 03:13 PM
gregr75
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Report this Post08-16-2022 09:19 AM Click Here to See the Profile for gregr75Send a Private Message to gregr75Edit/Delete MessageReply w/QuoteDirect Link to This Post
Jacked up the Fiero for a brake job and found some awful corrosion in a bad area, about 6 inches forward of the rear sway bar on the driver side.
I think this is the engine cradle?
I'm wondering what the best thing to do is.

1) Drop the whole rear suspension + tranny out, remove control arms, struts, etc, and rebuild with a junkyard cradle. I do have the tool that spans the rear and allows the engine to remain installed.
2) Do the same thing but perform a weld repair on that section of the engine cradle and rebuild
3) Do some kind of weld repair on the cradle while everything is still installed.
4) Something else?

BTW, I have zero welding skill.

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Raydar
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Report this Post08-16-2022 10:03 AM Click Here to See the Profile for RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
I would replace that cradle. I think it's pretty much done. Probably the easiest option.

But then, I live in the south, so I seldom see rust like that.
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Report this Post08-16-2022 10:19 AM Click Here to See the Profile for IMSA GTSend a Private Message to IMSA GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
There may be a bigger hidden picture here to where the car is not worth saving.....or maybe just the engine cradle needs to be replaced. Remove the rear wheels and wheel well liner and see if the entire frame has rusted away like this:

[This message has been edited by IMSA GT (edited 08-16-2022).]

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theogre
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Report this Post08-16-2022 10:35 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yes, is the cradle at minimum.

Replacing is your only option when rotted so bad like pic above.

Just there alone, Welding needs enough good metal to stick and you don't have enough after sanding/grinding. You likely have more places that are rotted that just don't tell as easy as above.

When I look to find "hidden" rot areas, use 2-3 lb hammer, and gently hit a lot of areas and listen and watch. "Gently" like hit small to normal nail w/ big hammer. you quickly hear, see or both hitting in big rot frame areas etc because have different sound or "metal" will bend easy.

Replacing the cradle can be done without dropping engine etc but need special tools etc to hold the engine up safely. Even w/ right equipment shown in Fiero and other FSM, no-one should be under the engine and rest of drivetrain. MORE SO w/ HF etc "universal" engine supports that are easy to slip or outright Fail. I would use the support and add extra chains etc to backup the support. Chains don't need to be pulled tight but not let engine to drop on you either.

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gregr75
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Report this Post08-16-2022 11:24 AM Click Here to See the Profile for gregr75Send a Private Message to gregr75Edit/Delete MessageReply w/QuoteDirect Link to This Post
Good idea on checking the other frame components.

I'm never gonna buy another 32 year old new england car at night. Should have looked underneath better. Hopefully its just this cradle.
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zkhennings
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Report this Post08-16-2022 11:47 AM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Replace that cradle, I have repaired rot in mine but that is excessive and there is probably way more hiding. Also since you have the setup to support the motor and trans it will be an easy job, I would drop cradle with the suspension attached and take it off once out of the car so you have super easy access to everything. I have a feeling you will be chopping the bolts out.

I like using a slag hammer for finding rust, has a very pointy end and you can really pin-point where the weak metal is hiding.

Oh and one more tip is you can remove the rear bumper and the crash beam underneath it for a straight shot to the cradle nuts that like to rust and then spin freely when trying to remove cradle. No need to cut holes in the frame to grab them which you so commonly see.

[This message has been edited by zkhennings (edited 08-16-2022).]

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Patrick
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Report this Post08-16-2022 04:00 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by IMSA GT:

There may be a bigger hidden picture here to where the car is not worth saving...


Exactly. It's hard to imagine that the frame rails aren't rotted away when the cradle is that far gone.
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sanderson231
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Report this Post08-16-2022 05:18 PM Click Here to See the Profile for sanderson231Send a Private Message to sanderson231Edit/Delete MessageReply w/QuoteDirect Link to This Post
I can probably gets you a parts car with a good frame for next to nothing if you want to haul one back from Texas

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gregr75
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Report this Post08-17-2022 09:29 PM Click Here to See the Profile for gregr75Send a Private Message to gregr75Edit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks for the offer @ sanderson231, I am looking at some used cradles on ebay for $350,400.

I am looking at whats actually involved in getting the cradle out. It appears after I get a low profile dolly underneath the cradle, and disconnect everything, I can lift the rear of the car over the cradle/trans/engine using a floor jack and 4x4 spanning the width of the car. Instead of using a cherry picker (which I don't have) to lift up the car. And then take apart all the crap to get to the cradle. I am looking at the following picture from skitime in the FAQ thread. https://www.fiero.nl/forum/Forum9/HTML/000024.html

After reading the thread, my only question, is, wouldn't this method crush the metal coolant lines running down the length of either side of the car. There doesn't appear to be much structure here too, just the floorpan?

I took a picture of me holding where I think the 4x4 is supposed to go, right by the spare tire jacking points. Of course it would span the width of the car, but again, I dont see this as a good support point to jack up the car. What am I not understanding?
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Patrick
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Report this Post08-17-2022 09:49 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by gregr75:

I am looking at some used cradles...


Have you looked at the rear frame rails yet? All your preparation could unfortunately be for nothing.
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zkhennings
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Report this Post08-17-2022 10:32 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
I have pulled the cradle in and out many many times from that 4x4 in that notch. Never damaged a coolant line in the slightest. A jack would mess it up, but a long 4x4 spanning the entire distance spreads the load out no problem.
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gregr75
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Report this Post08-17-2022 10:37 PM Click Here to See the Profile for gregr75Send a Private Message to gregr75Edit/Delete MessageReply w/QuoteDirect Link to This Post
I want to do it for the learning experience either way, there's some oil leaks around the engine/tranny so I'd like to get it out anyway and inspect closer
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Report this Post08-17-2022 10:41 PM Click Here to See the Profile for gregr75Send a Private Message to gregr75Edit/Delete MessageReply w/QuoteDirect Link to This Post

gregr75

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quote
Originally posted by zkhennings:

I have pulled the cradle in and out many many times from that 4x4 in that notch. Never damaged a coolant line in the slightest. A jack would mess it up, but a long 4x4 spanning the entire distance spreads the load out no problem.


BTW is it ok that the 4x4 wont even contact the notch at either side of the car? the notch sits above the level of the floorpan, possibly because of corrosion on my car? does it look like its missing material?

[This message has been edited by gregr75 (edited 08-17-2022).]

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Patrick
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Report this Post08-18-2022 07:14 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by gregr75:

I want to do it for the learning experience either way...


I'm not suggesting that you may be considering this... but please don't be tempted to install a solid cradle into a car with rotted frame rails, especially if you were to then turn around and sell it to an unsuspecting buyer. That would be totally uncool.

[This message has been edited by Patrick (edited 08-18-2022).]

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gregr75
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Report this Post08-19-2022 10:16 AM Click Here to See the Profile for gregr75Send a Private Message to gregr75Edit/Delete MessageReply w/QuoteDirect Link to This Post
I would NEVER do that.. if the frame rails are rotted I would be selling this as a parts car or find some expert welding shop. Back to my question, it seems the notch where the spare tire scissor jack goes sits about half an inch higher than the plastic and floorpan, therefore a 4x4 spanning the width of the car at this location wont be supported by the notch. Is this normal on fieros. The notch is fairly corroded on mine so I'm wondering if it "receded" upwards.

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willyt
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Report this Post08-19-2022 10:47 AM Click Here to See the Profile for willytSend a Private Message to willytEdit/Delete MessageReply w/QuoteDirect Link to This Post
I believe this is normal, at least my car looks the same, with less rust

I just lifted the car with this method - I used 6x6's, only because that's what I had laying around. 2 surprisingly small trolly jacks lifted the car as high as I needed to remove the engine with the struts still attached.

If you are planning on building your own dolly to set the cradle on I would suggest making sure you have sturdy enough wheels.... Trust me, that's not fun to learn the hard way.
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Report this Post08-19-2022 10:59 AM Click Here to See the Profile for willytSend a Private Message to willytEdit/Delete MessageReply w/QuoteDirect Link to This Post

willyt

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This also did not crush the coolant pipes on my car. The load is spread evenly over the floor pan which takes the weight.
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gregr75
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Report this Post08-19-2022 03:43 PM Click Here to See the Profile for gregr75Send a Private Message to gregr75Edit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks! This gives me the confidence to do it.
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Patrick
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Report this Post08-19-2022 04:16 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by gregr75:

I would NEVER do that.. if the frame rails are rotted I would be selling this as a parts car or find some expert welding shop.


Glad to hear it.

This is where to look at the rear frame rails behind the plastic wheel well liners...

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unplugged1981
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Report this Post08-19-2022 06:49 PM Click Here to See the Profile for unplugged1981Send a Private Message to unplugged1981Edit/Delete MessageReply w/QuoteDirect Link to This Post
I Agree with everyone here, welding the cradle could bring you major problems on the short or long time it’s better to find one on some scrapyard that it’s not rotten.
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zkhennings
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Report this Post08-24-2022 03:13 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
4x4 is not actually retained by notch, notch is just there so all the weight the 4 x 4 is supporting is not going through those areas. I would not lift the car from there with the engine installed in it, but it is perfect for lifting the chassis off of the subframe.

[This message has been edited by zkhennings (edited 08-24-2022).]

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