Top subframe bushing broke off in chassis. How to remove

[BaltimoreBimmer]

Hi. Have a convertible. Bushing broke off in my car. How the hell am I going to recover this?

[varg]

You can try to thread a big bolt into it (make it self-tapping by cutting angled slots into it) and pound on it from the inside with a drift, this is how I got mine out, though they didn't break off. Use a die grinder to get whatever is left out.

[BaltimoreBimmer]

You can try to thread a big bolt into it (make it self-tapping by cutting angled slots into it) and pound on it from the inside with a drift, this is how I got mine out, though they didn't break off. Use a die grinder to get whatever is left out.

Not really viable as I have a convertible. Practically no access from above. Perhaps something similar from below?

Is it a bad idea to slowly grind away the metal remains with a dremel? Is it realistic to do that and not mar the chassis? Or have they basically formed together as one now.

[varg]

Not really viable as I have a convertible. Practically no access from above. Perhaps something similar from below?

What? You don't have enough access to do this? I could've sworn there wasn't anything in the way of this hole in my stripped out convertible parts car.

Is it a bad idea to slowly grind away the metal remains with a dremel? Is it realistic to do that and not mar the chassis? Or have they basically formed together as one now.

Not a bad idea but it will take forever. Fairly easy to tell once you've broken through the aluminum to steel though. Yes, they're fused together, it's a perfect galvanic cell.

[ThatM20Guy]

I had to do what varg said to get my bushings out. Thread in a 5/8 (?) lag bolt into the bushing and then I dropped a 3/8 extension and pounded the shit out of it until it dropped.

If you have no access bushing from the top you could maybe use a slide hammer if you have enough room.

[gart]

Having gone through this in my convertible I'll chime in. What if did was start with a small drill bit from the bottom and drilled around the bushing stepping up in bits till I was close to the thickness of the bushing. Go slow and as varg said you will know when you are through the aluminum. Then I used a small screwdriver and pick to break out the pieces. Wasn't actually that bad and didn't mess up where the bushing sits. You may want to grind it flat and center punch to get a better start. Mine broke further up so I had a rough surface to start with. Let us know how it goes

[nrubenstein]

Carbide bits are your friends for this.

WEAR EXCELLENT EYE PROTECTION. I CAN NOT STRESS THIS ENOUGH. CARBIDE BITS PRODUCE RAZOR SHARP METAL SHARD DEBRIS.

[BaltimoreBimmer]

thanks for the input guys,

Here's what I am dealing with on the inside:



zooming in:



so as you can see, definitely a lot in the way compared to a coupe/sedan

I got my dad to give this a look and he also suggested perhaps a slide hammer. I think I will end up going with what gart said with the drill bits, however I can't see myself finding a drill bit that large (or a drill to hold it!) and my old man has the biggest of drill bit indexes (used to run a machine shop)

On second thought, first I will attempt to get a lag bolt screwed up in there from below, and then fish in a metal rod from above and try to hammer it down:





however, there is a significant bend required to make this work, so I am thinking the rod will give way before the bushing does - here is what the bend looks like:




So I'll attempt that, and then worst case scenario I will have to just drill it out I suppose. Very nervous about scoring the chassis side though

also nru, I always wear proper PPE, perhaps a bit overboard:



the other side came out clean, so I guess I can slowly drill it out and deal with the scoring :( I highly doubt the rod smashing method will work

[gart]

If you can't bang it out from the top and end up having to drill it out I wasn't saying use a giant bit to drill the whole thing out, most likely close to a .25 bit . Drill multiple holes around through the outer wall till it's only connected by thin pieces of aluminum. Like looking at a cylinder of a revolver. Once you get there they will just break out pretty easily

[BaltimoreBimmer]

If you can't bang it out from the top and end up having to drill it out I wasn't saying use a giant bit to drill the whole thing out, most likely close to a .25 bit . Drill multiple holes around through the outer wall till it's only connected by thin pieces of aluminum. Like looking at a cylinder of a revolver. Once you get there they will just break out pretty easily

that makes more sense, thanks for clarifying for my slow self. That would be a more desirable approach than a dremel. I will have to worry about going too far with the drill bit so that I don't go into the chassis. Luckily my other side came out clean so I can use that as a depth reference.

[Mook613]

The rod smashing is THE way to do it.
I used the method from the start and got both sides out without the bushing breaking at all.

Use a 1/2" threaded rod and a 5/8th lag bolt. Thread the lag bolt in as hard as you can and then smash with a BFH. I personally used a 4lb mini sledge hammer.
Took quite a few big hits and the subframe just dropped.

Yes I have a vert and had to bend the rod quite a bit, but no it didn't break.

[varg]

I guess I was mistaken. Wasn't the first time won't be the last.

[BaltimoreBimmer]

Not going well. Lag bolt plus massive sledge did not move it at all. Did manage to bash in my finger though...

Did several drill holes and stepped up the size however it's not wanting to collapse. It wants to fight me till the very end. I'm grinding and chisleing and grinding and hammering and grinding. Still have a ways to go. Need to buy different bits to make this work. Also it's incredibly difficult to tell where the bushing metal ends and the chassis begins.

It will come out. It's just being a huge pain

attempted lag bolt removal (actually not a lag but still bit):



here are some holes being drilled, I didn't start with toothpick sized like you gart, however I did find a hilariously small drill bit index of my dads. The index itself was no taller than my pinky and held maybe 10 bits. Quite cute, really.



and here is my mangled mess en route after realizing I have to shave it down. You can see the one (or two) point(s) where I possibly hit the chassis:



thanks for the encouragement gart, I need it. I look like a girl who has discovered glitter make up for the first time

[gart]

I feel your pain man. Had to do both of mine this way, they just wouldn't budge. I started with a toothpick sized bit and it wasn't hard to tell when you were through the aluminum. Keep at it, you'll get it.

[Northern]

I think I managed to chisel mine out. Second (much rustier) car I did the bushings on, I stuck an extension up through the hole and beat it fore/aft and it eventually worked the whole bushing/sleeve out intact.

If it broke off like yours, I'd probably drill/grind two holes 180deg apart and chisel the two halves toward each other.