Which Subframe Bolt to Loosen to Remove Lower Control Arm Bolt?

[arjun90]

I'm having a little trouble removing the front passenger rear lower control arm bolt. The fuel lines come in the way, and wiggling them doesn't help. Which subframe bolt(s) do I need to loosen (~1 inch) to get enough clearance (pictures below)? Thanks again

[Jesse_Boyer]

In my opinion, I'd at least loosen the front bolts a turn or so and turn the rear bolts several turns (enough to get your suspension bolts out.) If you only loosen the rear bolts, the subframe will almost have to be bent/tweaked as it's held firmly by the front bolts. There are four main bolts that hold the subframe to the chassis, but there are brackets you've identified as well. Those are 13mm heads and I'd just take them out entirely.

[arjun90]

I'm only able to count three discrete bolts--According to this user's thread ( http://www.audiforums.com/forum/diy-...l-arms-173211/ ), he only partially loosened the front 18mm bolt, is that approach with tolerance?

[glennda5id]

Is the ball joint separated from the upright? Once it's separated you should be able to twist the control arm and remove the bolt without releasing the subframe.

[arjun90]

That worked for the Driver Side, but on the Passenger side, the Fuel lines and Brake lines come in the way. I released the retaining clip which holds the lines. The ball joint was separated from the upright, I tried angling and wiggling / twisting the rear lower control arm to try to get the bolt out, but the lines are in the way--by a tiny fraction. It appears it will be equally difficult to fit the new bolt through. Almost no flexibility in moving the lines either.

Is the ball joint separated from the upright? Once it's separated you should be able to twist the control arm and remove the bolt without releasing the subframe.

[a4kamila6]

I loosen all three, leave a few threads in.

[arjun90]

Thanks!
I'm still stunned by how the placement of those lines are placed there. Still interested to know the reasons why Audi chose to go that route. Lol

I loosen all three, leave a few threads in.

[arjun90]

Also, aren't the subframe bolts torque-to-yield, thus one time use only? Would I need to replace them?

[a4kamila6]

Technically yes, they are stretch bolts and should be replaced. To each their own.

[Bordom]

I reused mine multiple times with no ill effects

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[arjun90]

Hey everyone, I overtorqued one of the M8x25 bolts while tightening them last night. The head of one of the bolts broke off and I need to use a screw extractor to replace it. Is it still safe to drive with one of the bolts not secured? The main subframe mounting bolt is still intact. Its odd when the two M8x25 bolts aren't really that tight, perhaps its just to protect the subframe from the elements or keep it stabilized against the body of the car?

[rgtorque]

probably dont need an extractor. once the subframe is out of the way you should be able to grab it with your hand and turn it out. the tension or friction keeping the bolt from spinning is on the seat of the head. once the head is broken off the bolt is actually loose. this is of course unless its cross threaded.

[arjun90]

Problem is that I can't remove the subframe. A bunch of others things are attached to it and the motor/trans are being supported by it as well. Is that bolt supposed to feel loose after over-torquing it? Is it suppose to wiggle? If that's the case shouldn't it be as simple as grabbing a tool (applying some adhesive to it) and slowly turning the broken bolt counter-clockwise?

probably dont need an extractor. once the subframe is out of the way you should be able to grab it with your hand and turn it out. the tension or friction keeping the bolt from spinning is on the seat of the head. once the head is broken off the bolt is actually loose. this is of course unless its cross threaded.

[Bordom]

So you broke on of the 13mm bolts on that bracket? Just take out the other 13mm, loosen the 18mm main subframe bolt enough to swing the bracket out if the way.

From there you should have all the space you need to drill/tap/extract the body of the bolt. No need to overthink it

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[arjun90]

Thanks, I'll definitely look into that, I should be able to get a pair of vise grips and just loosen once the shield is out of the way-- no need to drill and tap it seems. I would assume part of that bolt is still sticking out (without the head of course). It didn't take much torque to overtorque.

So you broke on of the 13mm bolts on that bracket? Just take out the other 13mm, loosen the 18mm main subframe bolt enough to swing the bracket out if the way.

From there you should have all the space you need to drill/tap/extract the body of the bolt. No need to overthink it

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