cracked subframe - should i worry MUCH?

[shobikes]

Howdy y'all-

Yesterday while replacing my rod bearings and y-pipe, while the starter was out and all that, I noticed a crack in the subframe adjacent to the forward engine mount. It looks like it propagates from the trailing edge of the subframe, where the reinforcement crossmember is welded to the main subframe. The crack runs from that weld point upward and around toward the motor mount bolthole, stopping about 1-1/2" from the hole. It hasn't opened up, not showing any signs of deformation. I can't tell whether it's cracked from the stress of the motor mount or the tension arm of the lower control arm assembly.

So my question: Next Wednesday, it's going to the muffler shop for custom catback. The exhaust guy is a master welder and has already said he can run a bead up the crack to allow me to ignore it for a little while. I have an extra subframe I was hoping to not have to pull off the parts car, so now I guess I will, but I need to get another daily driver together before attacking this task. Do you think if I get the crack welded before it propagates further, that I'll be OK to drive it another 10-15K before it cracks again? Is this common for these cars? I'm pretty sure it's recent - since the AL SFB's. Is this a side effect of the stiffer SFB's? Should I consider SFC's & would they prevent this type of occurence?

TIA, as always-

 

[jelloslug]

I would say any crack in the sub frame is somthing that should be address immediately. The stresses that are plced on the subframe by the engine, suspension, and the weight of the car are only going to make it fail sooner than later. I doubt that the AL bushings were the cause of the crack but they may make add more stress to the sub frame. I would go ahead and swap the sub frame since you have one at your disposal, just check that one out since there was obvious front end damage to that parts car. I'll give you a call later when your store opens.

 

[GEN1SHO]

I had the SHO Shop install a new subframe in my old 1990 because the prior one had been bent from an accident before I acquired the car. I also had the full canyon carver suspension package and engine support package. On one of my periodic visits they noticed a crack in the subframe and welded it up and said it would be ok for a while, but did recommend I eventually have it replaced. The car was totalled a few months after so it was replaced... with a new SHO
Good luck!

 

[MyFirstSHO]

I got alot of heat from this forum when I discovered my broken subframe (ALOT!). My break "sounds" (by the way you described it) like it was in the same vicinity as your crack is. (no pun intended )

Get some pics up if you have the ability. Mine was completely severed right where the stock welds were, next to the front motor mount. Looking on the drivers side on my car shows the stock welds and a nice gap, (I WILL get a pic up for this thread) while Ive looked at 2nd gen subframes in the same spot, without the gap.

I welded mine back up more than 6 months and 4000 miles ago with alot of hard pulls. It is as solid as the day it was welded.

Good luck,
Ryan

 

[shobikes]

My First SHO - If you're the guy I remember with the broken subframe, you've chilled out ALOT. Thank you.

So it seems this is perhaps not frequent, but at least not uncommon, to happen to the Gen I's. I'm gonna get it welded, perhaps reinforced, and keep an eye on it for awhile. I will also pull the extra subframe I have from the parts car, maybe even reinforce it before swapping them, and plan on changing it out before I make my big roadtrip this summer.

Thanks y'all!