B7 Rear Upper Control Arm - Upper Bolt STUCK

[goneAUDIcrazy]

I'm in the process of replacing bushings, control arms, bolts, etc on my B7 Avant. As I was loosening the bolt where the Rear Upper Control Arm mounts to the chassis, the nut that I assume is supposed to be welded to the chassis bar on the other side popped loose, now I can't get the bolt out, even though it's loose enough for the control arm to swing on its own.

I have tried to get a socket onto the nut on the other side of the chassis bar but it's not visible, and I can't seem to get any size I have on there.

Does anyone have any guidance?

[Okedokey]

Do you have air tools? Either way you can place multiple open ended spanners on the bolt head side to lever it off as you turn it. Try using heaps of penetrating oil and may be a jack under the knuckle to lift the whole assembly up to take the weight off.

[JayDog747]

You will have to lower the frame about an inch on the side you are working on and use vise-grips on the nut. Replace, tighten up the sub-frame before moving on to the other side.

[goneAUDIcrazy]

Do you have air tools? Either way you can place multiple open ended spanners on the bolt head side to lever it off as you turn it. Try using heaps of penetrating oil and may be a jack under the knuckle to lift the whole assembly up to take the weight off.

No air tools, it's not the weight, the control arm is disconnected completely minus the upper bolt. I feel like you are talking about the lower bolt?

You will have to lower the frame about an inch on the side you are working on and use vise-grips on the nut. Replace, tighten up the sub-frame before moving on to the other side.

I was hoping this wasn't the case. Do you happen to know the nut size and if it was originally welded to the frame?

I'll have to finish the rest of the suspension first so that I can get all 4 wheels off the ground......

[mtroxel]

Yea that's a well known bitch. I fought this last fall. I had no chance on that bolt. Read this thead, and see Denio's post number 9 with pictures. I finally took it too a shop. He dropped the subframe, heated that nut red hot, vice griped, turned a few turns, then re-heated, turned a few more, blah, blah, blah.

http://www.audizine.com/forum/showth...light=subframe

I was hoping this wasn't the case. Do you happen to know the nut size and if it was originally welded to the frame?

I don't think you can just replace the nut. The factory nut has a collar on it that is pressed in at the factory. Once it turns years later, you have to fight to get it out, clean up the threads, and weld it back in place. That collar centers the nut, and consequently the bolt, in that hole. And that location is very important to your alignment. Do not sacrifice or replace that nut.

I wish I had a better way. But if you search around, others have come to the same point as I was.

[goneAUDIcrazy]

Tackling this task one day this week, thanks for the help everyone, not sure how I couldn't find more info on this, wrong search terms I guess.

[Tsinsta93]

Yea that's a well known bitch. I fought this last fall. I had no chance on that bolt. Read this thead, and see Denio's post number 9 with pictures. I finally took it too a shop. He dropped the subframe, heated that nut red hot, vice griped, turned a few turns, then re-heated, turned a few more, blah, blah, blah.

http://www.audizine.com/forum/showth...light=subframe



I don't think you can just replace the nut. The factory nut has a collar on it that is pressed in at the factory. Once it turns years later, you have to fight to get it out, clean up the threads, and weld it back in place. That collar centers the nut, and consequently the bolt, in that hole. And that location is very important to your alignment. Do not sacrifice or replace that nut.

I wish I had a better way. But if you search around, others have come to the same point as I was.

Bumped for the link to a helpful thread

[Jayz691]

Its a press-fit nut, no actual size. Not welded but pulled into place when tightened. Need to lower the subframe a good bit to get something on it, to hold it. I used a small pipe wrench to hold it, worked good.

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[Tsinsta93]

Its a press-fit nut, no actual size. Not welded but pulled into place when tightened. Need to lower the subframe a good bit to get something on it, to hold it. I used a small pipe wrench to hold it, worked good.

Sent from my LM-G710VM using Audizine Forum mobile app

Yeah with it cleaned up it seems to have about 8 sides. I tried holding it with a vice grips and crescent wrench but the threads have bound up terribly trying to loosen it. It travels about a 1/4" and then gets stuck. I'm just going ahead with ordering genuine nuts and bolts and am going to cut and split the nut to get around it. One of my knuckle-side eccentric bolts was also seized (the main reason I'm doing this project), so at this point I think i have spent as much on these nuts and bolts as I did on the replacement arms!

[Jayz691]

Yeah with it cleaned up it seems to have about 8 sides. I tried holding it with a vice grips and crescent wrench but the threads have bound up terribly trying to loosen it. It travels about a 1/4" and then gets stuck. I'm just going ahead with ordering genuine nuts and bolts and am going to cut and split the nut to get around it. One of my knuckle-side eccentric bolts was also seized (the main reason I'm doing this project), so at this point I think i have spent as much on these nuts and bolts as I did on the replacement arms!

I did the same, bought Moog arms, and low milage used lower A-arms. All new hardware, all 4 eccentric bolts were seized. Actually just did the 2 big arms a week ago. Worth the headache though, cuz now it drive beautifully, with fresh alignment. Heres a pic of that pressfit nut, believe it is 8 sided(prob special socket, frickin Audi). Good luck.Screenshot_20200922-115510.jpg

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