Sub frame bolt removal

[bvolks73]

Does anyone have any tricks for removing the bolts that hold the front sub frame on a MKII Jetta? The 2 that hold the control arms came out easily (since the control arm bushings have been replaced several times) but the other 2 don't want to budge. I've been spraying Liquid Wrench down into it every day but have no idea if it's actually getting to the nut and since the nut is inside the body there's no way to heat it. As a last resort I'm going to try my neighbour's impact wrench but figured I'd check if you guys had any tricks that might work. I really don't want to break those bolts off.

[dieselweasel]

The three things useful for loosening seized parts are penetrating oil, heat, and impact or shock force.  One you can't use, the other you've done.  
Definitely try the impact wrench.  Just go easy on it, and try spinning it alternately in forward and reverse to break the bolts free.

[jtanguay]

you might need a lot of patience too... i broke one off a car...  :lol: patience was running out!!! but i intended on buying a new bolt & using anti seize on it  :wink: if the old bolt is that crusted, it's only a matter of time before it gives.

[Dakotakid]

Use a blunt bolt or round-faced chisel and use a large ball peen to apply a shock wave into the head of the bolt a multitude of times. Yes, the car will have to be on a hoist or hire a midget for a day........

Try "rocking" the bolt slightly between tighten and loosen and smack it some more with the hard steel bolt. Take a pint under there with ya and make a day of it.

Sooner later....something's got to happen.

[Turbinepowered]

Torque. I dropped the subframe on the Fox by slipping a breaker onto the bolt, puttling a block underneath to keep the socket on the head, then used a 5' length of iron pipe slipped over the breaker handle. Gave me some 5' of leverage to push against.

Four extra feet of leverage = one unstuck bolt!

[VelocityConservation]

Be very careful with the impact gun.

I wrung the head off of one of my subframe bolts trying to get it out.

It soaked in penetrating oil for a week and I was shuttling between forward and back when the bolt broke.

I decided I really didn't need to take the subframe out.  Welded the bolt to the subframe and moved on.

VelocityConservation

[Turbinepowered]

Stuff like that is why I prefer just adding leverage when I can over using an impact gun. Leverage tends to be gentler and less shocking, which in my experience leads to fewer broken bolts.

[commuter boy]

In places where I couldn't get a torch into heat something I've used a large soldering gun to touch the tip of the bolt to heat it.

[bvolks73]

Got them out. I heated them up the best I could and they came out fairly easily with an 18" power bar. One of them looks like new but the other one is pretty thin in one spot. Threads on both were good though. I'll definitely be putting new bolts in when I put it back together.

[thomas m]

Just the thread I'm looking for !

Lots of questions, lots of ideas and the good judgement to exercise a lot of patience !!

A belated thank you !!

[fatmobile]

  Impact is a good idea but it's often better to hit them with a hammer, straight on the head, to break the rust in the thread.
 Turning with an impact wrench can break them off.