Those rusty eccentric bolts in the rear

[SlickFix]

I spoke to the highly regarded Alignment shop today, and he told me that if the rear eccentric bolts are rusted solid, that they would either not be able to align the rear(if that's even needed) or would have to order the bolts in and then replace them.

So my plan is to order new bolts this week and replace them myself before I even take it to them. Do you guys agree with this plan, or should I just hope that the rears are already in alignment and bring new bolts along just in case they need to move them. The eccentric bolts did look incredibly rusted when I was down there replacing stuff.

I'm planning on giving them a PB Blaster enema. Is it safe to use mapp gas on those bolts, or are the bushings too close?

The car does seem to be the slightest bit out of alignment after replacing the suspension last weekend.

[customa4]

Just take your wheel off and test it for yourself. Throw a ratchet on there and loosen it up, if it loosens just bring it to them and when they tell you it needs new bolts you call bull shit. Either way your going to be getting an alignment so it won't hurt to loosen them and tighten them back.

[agart]

I just replaced those a few weeks ago. One eventually broke free and I didn't need to replace the bolt. The other was seized into the bushing and I couldn't get it free after a lot of effort. Ended up having to pull the entire control arm out, pressing the bushing out and replacing it. You won't know what you're in for until you take a look.

[lookaught]

Exactly. Often it's corroded and frozen to the bushing... so you can turn it but it's just twisting the bushing. If this happens it is no easy task to remove, you basically need to remove it and drill out the old bolt, then press out or hammer out the bushing, and then replace. The bushings aren't expensive but this procedure is a serious PITA.

[SlickFix]

So, what you guys are saying is that even if the nut breaks free and is able to spin, the actual bolt itself can be seized into the bushing? And let me guess, there's not enough room to hammer the bolt out the other side, is there?

[evo_ski]

The rear toe bolt hits the gas tank if you try to remove it, so to remove the toe bolt you have to completely drop the subframe. Mine is stuck and I can't figure out a good way to fix it. The camber bolt will likely be a bit easier to remove since there is a lot more room to get at it.

[Steve Bassen]

Galvinic corrosion FTL... I did mine about 2 weeks ago as part of an ongoing suspension/driveline overhaul on my Avant. The upper (camber) eccentrics were completely seized to the bushing sleeves and had to be cut out with a sawzall and replaced with fresh hardware. The lower (toe) eccentrics were stuck at first, but a generous application of Kriol oil and a 3 foot breaker bar worked them loose, eventually. Rotating them a few times got me to the point that they could be pulled and have a tap run on them to clean up the threads, before reinstalling them (with antiseize on the shank). BTW, subframe removal helps for doing this :p

Subframe out


Rear upper arms cut out (the inner non-adjustable bolts needed the body nut re-welded, too)


Fresh bushings


All back together


And, yes, this is a pretty horrible procedure to do.

[dougyfresh]

The bolt that attaches the upper control arm to the subframe has a hidden nut. The nut is pressed into the subframe. Often this nut becomes loose and then you can not remove bolt. This becomes a problem if you have to replac the control arm due to the eccentric bolt breaking of frozen in the bushing.

I removed my subframe and welded the upper control arm nut to the subframe so it will not come off. I thought I created a thread about it and posted photos but I can not seem to find it via searching.


EDIT:
Found my post. It was on another forum and a year older than I thought (was looking in the 2011 timeframe)
http://www.euroaddiction.net/forum/b...html#post79812

[Steve Bassen]

The bolt that attaches the upper control arm to the subframe has a hidden nut. The nut is pressed into the subframe. Often this nut becomes loose and then you can not remove bolt. This becomes a problem if you have to replac the control arm due to the eccentric bolt breaking of frozen in the bushing.

I removed my subframe and welded the upper control arm nut to the subframe so it will not come off. I thought I created a thread about it and posted photos but I can not seem to find it via searching.

Yeah, your thread on the subframe removal and hidden nut working itself loose issue is what convinced me to just drop the whole subframe instead of messing with that crap while it was in the car.

[dougyfresh]

Yeah, your thread on the subframe removal and hidden nut working itself loose issue is what convinced me to just drop the whole subframe instead of messing with that crap while it was in the car.

Cool! Glad to hear it was informative and helped you

[evo_ski]

Any chance there is a possibility of lowering the subframe just slightly to replace the toe bolts on the rear, or does it need to come out completely to be able to get the bolt out and the new one in?

[87supraman]

It is possible to get to those out with just lowering the subframe. But you may have to drop the rear exhaust mounts at the mufflers and watch your brake lines (ebrake and fluid lines). And you will need to remove the rear shock bolt to allow it to drop far enough.

Sent from my SCH-I545

[JPC1.8t]

Would it be bad/dangerous to forego welding the hidden nut and instead replacing it with a standard nut and possibly a lock washer?

I don't know the exact purpose for it being pressed in, maybe diagnosticator can chime in, I suspect it's just for ease when making repairs at the dealer?

I pulled my subframe to replace all my rear alignment bolts and my pressed nuts are toast.

Also.. Is there a way to recondition or replace the horseshoe thing that holds the abs sensor wire and also contains the eccentric washer for adjusting the camber?

[easyAudi]

EDIT: Found my post. It was on another forum and a year older than I thought (was looking in the 2011 timeframe)
http://www.euroaddiction.net/forum/b...html#post79812

Sry to resurrect...but hoping for feedback specifically on re-installing the rear subframe, from those that have removed it.

dougyfresh - do you recall any major issues re-installing the rear subframe? Any problems getting a *good* alignment done afterwards? Any other insights you remember...from 10 years ago..(!).

SlickFix (if you're still around): anything you remember about your work? Did you end up dropping the rear subframe? Any insights or things to avoid?

Thanks in advance to all.
And for anyone else stumbling on this :
press/recessed nut: N91036002 / N-910-360-02

Direct link to the internet archive of dougyfresh's quoted original thread [ euroaddiction site is perhaps long gone.. ]
https://web.archive.org/web/20130603...html#post79812

[Dr.B6Banter]

Sry to resurrect...but hoping for feedback specifically on re-installing the rear subframe, from those that have removed it.

dougyfresh - do you recall any major issues re-installing the rear subframe? Any problems getting a *good* alignment done afterwards? Any other insights you remember...from 10 years ago..(!).

SlickFix (if you're still around): anything you remember about your work? Did you end up dropping the rear subframe? Any insights or things to avoid?

Thanks in advance to all.
And for anyone else stumbling on this :
press/recessed nut: N91036002 / N-910-360-02

Direct link to the internet archive of dougyfresh's quoted original thread [ euroaddiction site is perhaps long gone.. ]
https://web.archive.org/web/20130603...html#post79812

In trying to replace my rear control arm bushings and subframe bushings with poly for the track, I'm going through this same process this winter and running into the same findings described above. I should have everything back together in a month or 2 so I'll report back if I have any issues with getting a good alignment.
I know for certain that the front subframe has alignment points to the chassis in the wheel wells where you can use a VAG tool to confirm everything is in line but not sure if there is such a thing for the rear subframe.

[codemode]

Unfortunately there aren’t any alignment points for the rear. Don’t know why they did that.

[easyAudi]

...I should have everything back together in a month or 2 so I'll report back if I have any issues with getting a good alignment.
I know for certain that the front subframe has alignment points to the chassis in the wheel wells where you can use a VAG tool to confirm everything is in line but not sure if there is such a thing for the rear subframe.

one install tip - tighten and seat this press-nut before final subframe installation. (I'm assuming you're getting new press-nuts. sadly, only available from audi)
Tighten the bolt to make sure this fully sets in place. Mine tightened down fine, but a closer look and they weren't properly seated and started crushing the lip of the press-nut mounting hole. I would have never seen it if I first bolted up the subframe.

Thanks for adding to this, and let us know what you learn w/the alignment. Finished my rear subframe a while back, but I haven't done an alignment yet, as I'm finishing front control arms, shocks ,etc.

...the front subframe has alignment points to the chassis in the wheel wells where you can use a VAG tool to confirm everything is in line but not sure if there is such a thing for the rear subframe.

For the front alignment holes, you can use the stock lugnut wrench/handle. ..it's a really good fit. Not perfect, but no need to buy the tool. And 2nd what codemode said - no alignment holes in the rear.

[Dr.B6Banter]

Just got the rear end back together and got an alignment. I’m still trying to dechiper the alignment results but seems like they didn’t have any issues dialing it in.

Interestingly on the front passenger side of the rear subframe, there seems to be a grommet covering a hole in the body that lines up with something that looks like an alignment tab on the subframe. A similar alignment tab exists on the rear drivers end of the subframe but no such hole in the body to aid with alignment.











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