broken front control arm bolt - B4 passat

Hi all - decided to do a full suspension refresh on the passat I picked up.

Tried to loosen the front control arm bolt and it broke about an inch below the head. This leave the bolt about halfway though the front control arm bushing, with no access to it.

Any ideas on where to do from here? I'm thinking about getting a sawzall on the bolt (between the control arm and frame) and cutting it to at least get the control arm out.

Thanks

Getting the control arm out to have access to the rest of the bolt sounds like the right place to start. Sawzall as needed to make that happen.

Yes - once you get the control arm out, use a torch to get the remaining bolt red hot. Then get some vice grips clamped to it and slowly work back and forth as it cools. Once you get one complete turn, things get easier.

starrd said:

Yes - once you get the control arm out, use a torch to get the remaining bolt red hot. Then get some vice grips clamped to it and slowly work back and forth as it cools. Once you get one complete turn, things get easier.

Click to expand...

To get the control arm out would involve cutting the bolt flush with the frame. Then it goes through to the captive nut on the inside (if its the same as my mk4)

I imagine I'll need to cut the subframe to get the bolt out - after it goes through into the subframe it there much to grab onto on the other side?

Drill it out with a left hand drill bit or use an Easy Out. Heat will help to break the rust free. I would avoid cutting into the subframe if you can, but if you have to, use a hole saw so you can easily patch it after.

I don't know how much of the bolt will stick through the back side, but I doubt there will be much.

Another option would be to sacrifice the control arm and cut it off around the bolt. That would leave something to grab with the vice grips. I generally don't have access to a welder or torch, so my repair methods would probably focus on trying to use penetrating oil, propane torch heat and a vice grips and maybe an air chisel if I could get it to bite. If not, I would take a hammer and chisel and try to get the bolt to turn counter clockwise. If that failed, then I would try a left handed drill bit (cuts when turning counter-clockwise instead of clockwise) and an easy-out.

lol, looks like Abacus snuck in here with the same advice while I was typing.

Hmm great ideas guys.

Sacrificing the control arm is something I had though about, but I think that the counter clockwise drill bit might be a better option.

I Had this happen on the LF forward bolt on my B4.

I pried the control arm as far forward on the broken bolt as possible, then sawzalled the bolt.

I pried the control arm out, and was left with about 3/16" of the bolt left in the captive nut.

I heated the metal around the bolt and vicegripped it out.

I had to beat the K-Frame metal back into shape slightly, but all was fine in the end.

A little update.

I ended up sacrificing the control arm cutting it off, then cut around the bushing to have access to it.

I removed the rubber, and the metal sleeve for the bushing had completely seized to the frame as well at the bolt.

I used to pairs of vice grip to turn it out, and it worked. Thanks for all the suggestions.


Now I went onto the other side, and that bolt seems just as stuck. Heating, oiling, hammering, impact wrench, nothing yet. I will be grabbing something to chill the bolt down and hopefully I'll be able to get it to move.

Sorry for the grief. Still better than the glued-on captive subframe nuts on the Mk4 though...

Dealing with the exact same scenario here - forward (horizontal) control arm bolt snapped, leaving a ~1cm stud that is still holding the bushing captive. It was heavily corroded, unlike the rearward (vertical) bolt that, other than its head, is shiny and looks brand new.

This inspired quite a rant about the so-and-sos in Wolfsburg, which I'll spare you. Just a quick question for now:

Is the rear bushing supposed to be able to come out before the front does? I can't tell but there might be somekinda groove in the subframe that makes it move only one way. If I can get the rear to swing out, I just might be able to pry the arm out - in spite of the captive stud - and deal with the stud with vicegrips, PB blaster, and heat.

Left-hand drill bits seem unnecessary if the stud falling into the subframe cavity is acceptable.

I have used a product called "freeze-off" by crc at work it has been helpful when all else fails. Might be helpful to you

Ended up welding a lug nut to the stud, letting it cool (important), and hammering loose with a boxed-end wrench. It took two welders, half a dozen nuts, several days of PB Blaster, and it fought hard until the very end.

From a maintainability standpoint, this part of the front suspension is a really bad design. They should not be TTY or use captive nuts, especially in such a corrosion-prone area.