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Calvinator

Swapping wheels today and I see front passenger subframe cracked, rusted.  This 1996 Grand Prix is too sweet to send to junk yard.  What repair should I be looking for ?  Frame shop weld-r-up?  Is there a reinforcement kit ?  Or a complete subframe replacement ?  THANKS

 

sideshot.jpg

cracked from side.jpg

cracked underneath.jpg

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I would probably just have it welded or swap it out.  Subframes aren't too difficult to remove, but you need something to hold the engine up while doing it.

Edit: yeah, I realize I didn't pay enough attention to the rust, lol.  Welding is obviously not an option

 

Edited by pwmin
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Swap it out completely with a clean one from a southern car. I see your old intro post says that's a Florida car(if this is the same '96?)...that subframe looks terrible if it's only been in Ohio a few years and was originally always a Florida car.

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That doesn't look very happy at all,  tell us, how long have you owned the car to only notice that now & how the hell did it pass Ohio safety inspection?

 

as suggested, look for a complete replacement. If there's rot there, where else is it?

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That front subframe is worthless.  It won't weld.  It'll just fall apart somewhere else.
As people said, replacing the front subframe isn't "too bad".  I've hand-rebuilt 3 rear subframes on my GM cars over the years.

With the front subframe,
1) Make sure you can get the rubber bushings.  They are hard/impossible to get for some years/models.

2) Get new bolts.  It's a good idea to get new nuts, if you don't want to risk an additional 1-3 weeks of down time.

3) Removing the old bolts may be easy (people in So-Calf often say "WTF are you talking about that a frame/body bolt is hard to remove").
Most of the times, it's very hard and requires the correct use of heat.
If you use heat, cut off the old bushings first (hence, why you need/want new bushings :)).  The smoke from burning bushing is very toxic.
Or "impossible".  And, I do mean impossible as per the correct dictionary definition.  The bolts and nuts can become fused(/one) through rust and electrolysis.  In those cases, the bolts get snapped, the old nuts removed, and new nuts(welded in) and bolts get used.


4) Finding a local rust-free front subframe may be very very hard, depending where you live.
For the rear sub-axle assembly on my Olds Achieva, I spent 9 months looking at every place withing a 2+ hour drive.
I strongly suggest that you check it out in person first.  Although, GM front subframes aren't as susceptible to rust.  Still, of the car/subframe sat for a long time in a wet area (mud, grass, snow, etc), then they can rust very quickly.

 

Btw, tranny shops in New England deal with the above issues every week.  It may add ~~1/2hour of time overall.  It's like dealing with exhausts here in New England.  The pros have the experience and the tools, and stuff like this is often quickly dealt with.  For the DYIer, it can be many hours/days, and a lot of money. 😪
For example, I now have a Mini-Ductor Venom Portable Induction Heater to help me remove rusted bolts/nuts.  What used to take me hours/days/weeks/forever, it now less than a few minutes. :)


Btw, I agree that the cost/effort to replace the front subframe is well worth it for a half decent car.

Good Luck!

 

 

Edited by Cutlass350
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pontiac6ksteawd

I thought there was a aluminum sub-frame that could be used in place of the steal one? From a 2005 or something Grand Prix.

Like this one.. I THINK

https://www.ebay.com/itm/05-07-BUICK-LACROSSE-Engine-Crossmember-Front-Cradle-Cross-Member-Control-Arms/283454114232?fits=Model%3AGrand+Prix&hash=item41ff2e89b8:g:lg4AAOSw4BBctgo3

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3 hours ago, pontiac6ksteawd said:

I thought there was a aluminum sub-frame that could be used in place of the steal one? From a 2005 or something Grand Prix.

Like this one.. I THINK

https://www.ebay.com/itm/05-07-BUICK-LACROSSE-Engine-Crossmember-Front-Cradle-Cross-Member-Control-Arms/283454114232?fits=Model%3AGrand+Prix&hash=item41ff2e89b8:g:lg4AAOSw4BBctgo3

I thought you had to swap knuckles and other things to get them to work, but I haven't really looked into it much.  The aluminum subframe on my old 06 was so much nicer and much lighter.

 

I've had these subframes out a bunch of times, too.   I have access to a lift and it's always been fairly rust-free cars, so I've never had a problem with bolts, but I know that's not the case everywhere.  The worst part to me has always been taking the steering pinch bolt off and getting it back on. 

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I learned you can hang a bungee cord from its midpoint off the master cylinder then hook the covering boot with both ends to hold it out of the way of that pinch bolt. I`d thought I`d have an issue getting it back on the R&P correctly but havent gotten that far yet.

Engine bay support bar is a must for getting one of these things off, $50 Harbor Freight one and a HD ratchet strap around the trans works great. I dont think getting your current one off will be an issue, it`ll be finding a suitable replacement without it having to be shipped. I recall the subframe swap thread as will and wished I would have paid better attention as to what needed swapped over to get them to work.

According to Crazy K and Jman093 from 2012 the 1st and 1.5st will NOT fit on a 2nd gen. 

 https://www.w-body.com/topic/49121-newer-impala-aluminum-subframe-compatibility/

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Raw deal on the subframe.  Like others have said it swap it out your ride looks pretty good otherwise.  I’ve never seen one that bad before even at the JY.  Rust free may be impossible to find but if you can find one in good shape it may be worth while to get a body shop to acid dip it to kill the surface rust inside and then coat it.   Hope the rear is ok?  

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