Sunfire sub frame
spddmn1
12-21-2012, 08:14 PM
Hey everyone got a question. I've got a friend who bought his son a 2001 Sunfire. His wife emailed me & asked if i could replace the subframe. I do light auto repair in my garage at home. Never done anything like this & told them i'd have to see. Was wondering if anyone has replaced a sub frame before & what's involved. I'm 40 years old & have been working on cars since i was 20. Can do almost everything except rebuild a engine or tranny. Also what do you think it would cost labor wise? Thanks.
MagicRat
12-21-2012, 10:24 PM
My observations:
1. Whats wrong with the subframe? Rust? Accident damage? Both problems may have damaged the rest of the car, rendering it impractical to repair. The subframe mounts, where the frame attaches to the body are known for rusting out. You may find they have simply crumbled and are too weak to safely support the subframe.
2. Even if the damage is isolated to the subframe, I think this job is simply too difficult and dangerous for a home garage set-up. A mechanics shop lift is required to do this safely.
3. Even with a lift, this is a huge undertaking. It's complex and time consuming. The relative cost is probably more than the car is worth.
I think the easiest way is to remove the hood, place several 2x4 wooden rails across the top of the engine, between the fenders. The engine and transmission are securely chained to the rails. The car is lifted on a hoist and wheels removed. Then the engine and transmission mounts are removed. The idea here is the entire weight of the driveline is supported by the 2x4 rails. Then one would remove the control arms (the struts would remain bolted to the body), sway bar and steering rack.The Then the car is lowered towards the ground and the subframe is supported by jackstands. It is unbolted from the body, and the car is raised, leaving the subframe sitting on the jackstands. Reinstallation would be the reverse procedure.
I am sure there are steps I am missing, here, but for the first-timer there is plenty of risk, of heavy parts becoming dislodged and falling down, causing injury/death. You can see, without a hoist, the car would have to be raised on stands quite high for access, amplifying the risk of the car falling off. Access to the necessary components would be difficult.
So, generally I think the entire operation would be a nightmare outside of a well-equipped mechanics shop. IMO its easier to get another Sunfire and use this one for parts.
1. Whats wrong with the subframe? Rust? Accident damage? Both problems may have damaged the rest of the car, rendering it impractical to repair. The subframe mounts, where the frame attaches to the body are known for rusting out. You may find they have simply crumbled and are too weak to safely support the subframe.
2. Even if the damage is isolated to the subframe, I think this job is simply too difficult and dangerous for a home garage set-up. A mechanics shop lift is required to do this safely.
3. Even with a lift, this is a huge undertaking. It's complex and time consuming. The relative cost is probably more than the car is worth.
I think the easiest way is to remove the hood, place several 2x4 wooden rails across the top of the engine, between the fenders. The engine and transmission are securely chained to the rails. The car is lifted on a hoist and wheels removed. Then the engine and transmission mounts are removed. The idea here is the entire weight of the driveline is supported by the 2x4 rails. Then one would remove the control arms (the struts would remain bolted to the body), sway bar and steering rack.The Then the car is lowered towards the ground and the subframe is supported by jackstands. It is unbolted from the body, and the car is raised, leaving the subframe sitting on the jackstands. Reinstallation would be the reverse procedure.
I am sure there are steps I am missing, here, but for the first-timer there is plenty of risk, of heavy parts becoming dislodged and falling down, causing injury/death. You can see, without a hoist, the car would have to be raised on stands quite high for access, amplifying the risk of the car falling off. Access to the necessary components would be difficult.
So, generally I think the entire operation would be a nightmare outside of a well-equipped mechanics shop. IMO its easier to get another Sunfire and use this one for parts.
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