Slowly working on fixing some issues with a R52 S JCW that I bought in 2023. This summer I am tackling replacing very worn bushings on the front control arms. While I am at it I figured I would replace the sway bar bushings, and power steering hoses that have a bit of a leak, as well as replace the struts from the factory orginals with 235K km on them. I bought the car basically to teach myself how to fix a car, so it is a learning experience, and every 2 hour job usually takes me the better part of a week it seems.

All going well, lots of good information out there on how to drop the subframe to get to all the parts. I probably should have been more patient and let a few of the bolts soak with some penetrating oil overnight, but long story short I busted one of the two bolts that holds the rear bushing on the driver side front control arm. I figure I am not the first to have run into this problem, but I can't find anything online with any tips or tricks on where to go from here. Maybe people who snap bolts don't admit it online, I don't know.

Any advice on how to get the last bit of a snapped bolt out of the subframe. It is snapped off within the subframe itself, nothing sticking out. So far I am just going to keep blasting it with penetrating oil until I have an idea how to tackle it.


Green circle of where the bolt is snapped off inside the subframe.

 

If you have a welder you could weld a nut on and wrench it off. The heat from welding will likely burn off the rust, and it should come off easily. If you don't have a welder or someone to take it to weld, you will probably need to drill it out and tap it. I've never had much success with easy-outs, but others have, so you may want to try that before drilling it out. To drill out, start with a small bit and then work your way up. It's important to stay on the center of the bolt when drilling the hole.

 

Thanks. It is snapped off inside the bolt hole, and welding isn't something I have tackled yet. Going to try to give it a good soak with penetrating oil (which I should have done in the first place) and then give it a go with an extractor bit, hoping not to have to drill it out entirely and try to fix the threads.

 

I'd give it a coating of penetrating oil once a day for a few days, then heat up the surrounding area with a torch. Then try the extractor.

 

Upload a pic of the snapped bolt. This could give us some kind of idea how to approach it.

 

I had to extract a bolt I snapped off in my engine block a couple of months ago, so as you can imagine I was sweating bullets to ensure I did this process correctly. Thankfully I work with a machinist who extracts broken off bolts every day so I went to him for advice. This is what he told to me and I followed his instructions exactly and it worked like a charm:

1. Get the right diameter extractor and drill bit for the diameter of the bolt you are trying to extract. The machinist recommended the coarse spiral fluted style of extractor, not the fine threaded type. If this is an M14 bolt, you will want about a 6mm drill bit and a #4 extractor, depending on the style of extractor you use.

2. Center punch the exact center of the broken bolt to provide your drill bit a spot to start in, if you don't then your drill bit will wander. You need to drill down the center of the bolt pretty precisely so cannot skip this step. If the top of the bolt is ragged you might want to use a Dremel or other tool to grind the surface flat first. You said it snapped within the subframe so grinding the surface flat is probably not possible for you.

3. Use a center drill to start the hole. This is not a required step and most people don't have center drills so you might skip this. But center drills don't wander or flex and they are less prone to snapping off like a standard drill bit which has the same diameter from end to end. Take your time, patience and moderate pressure is what is needed to do this without breaking bits and making the situation worse.

4. Tape the drill bit at the depth you want to drill to and drill it to that depth, being very careful to check that you are not drilling at an angle to the bolt (check the angle of the bit from multiple positions). Again, take your time, don't put too much pressure and keep it centered.

5. Once you have it drilled properly lightly tap the extractor into the hole with a hammer and then twist it out.

I hope this helps.

 

Any update on the extraction?