Replacing the curved lower control arm

**jfo** · 05-06-2018 04:19 PM

My curved lower control arm has a leak in the hydraulic bushing and a replacement is on order. I had a quick look at the bushing bolt and it looks tight for space, especially for a torque wrench. Any advice or comments on replacing it?

**flowhigh** · 05-06-2018 04:29 PM

You should still be able to turn full lock on the B8 and remove the CVjoint from the spindle. That should give you more work room. The challenge is getting the ball joint out of the spindle, most of the times it usually is seized on and you'll need a ball joint separator. You can do the work without removing the uppers.

Also, the curved bolt is on the bottom and is not as difficult as straight as the nut is on the bottom of the spindle. I'd start at the subframe side and unbolt there first as I support the spindle with a jack. You should be able to do it without removing the CV or the lower straight.

**jfo** · 05-06-2018 04:48 PM

I have a ball joint separator and I'm not too concerned about that end. It's the space at the subframe end I'm referring to.

**flowhigh** · 05-06-2018 05:17 PM

Yeah, now I see. The subframe might need to be dropped. Or you may be able to get two box wrenches from the topside of the subframe. You may have to remove some plastic undercover.

**Theiceman** · 05-06-2018 05:55 PM

Thats hydraulic ?

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**jfo** · 05-06-2018 06:46 PM

Originally Posted by Theiceman

Thats hydraulic ?

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Yes, that bushing was changed to hydraulic around mid to late 2010 production.

**choppstixxx** · 05-06-2018 07:10 PM

Just did this exact thing the other day on my 2013 B8.5. If your doing the passenger side you do not need to mess with the sub frame or even the X brace at all. Just remove the felt cover that goes over top the X brace and the plastic cover next to the pinch weld jacking point. Then remove the three bolts that attach the metal heat shield(one bolt is on the back side near the dp flex joint), slide that loose and move it out of the way so you can utilize a ratchet on the bolt end.
The ball joint end you will need a separator tool that looks like a massive “clip”. Pops right out with that tool, just make sure you lube the threads/bolt and tighten slow.
Make sure when you are installing the new control arm you put the arm under load before you tighten the bolt that attaches to the sub frame. I had the luxury of using a 2 post lift, so I used a standard jack/long piece of wood to jack up the control arm to the height when it’s on the ground normally. Then tightened the bolt/nut to spec.

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**flowhigh** · 05-06-2018 07:18 PM

Originally Posted by choppstixxx

Just did this exact thing the other day on my 2013 B8.5. If your doing the passenger side you do not need to mess with the sub frame or even the X brace at all. Just remove the felt cover that goes over top the X brace and the plastic cover next to the pinch weld jacking point. Then remove the three bolts that attach the metal heat shield(one bolt is on the back side near the dp flex joint), slide that loose and move it out of the way so you can utilize a ratchet on the bolt end.
The ball joint end you will need a separator tool that looks like a massive “clip”. Pops right out with that tool, just make sure you lube the threads/bolt and tighten slow.
Make sure when you are installing the new control arm you put the arm under load before you tighten the bolt that attaches to the sub frame. I had the luxury of using a 2 post lift, so I used a standard jack/long piece of wood to jack up the control arm to the height when it’s on the ground normally. Then tightened the bolt/nut to spec.

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Did you change the driver's side?

**choppstixxx** · 05-06-2018 07:32 PM

Originally Posted by flowhigh

Did you change the driver's side?

Only the passenger side, but I’d assume it’d be pretty similar. I don’t think the drivers side has the heat shield, so it should be theoretically easier.

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**jfo** · 05-06-2018 09:34 PM

Mine is the driver side. I've had a quick look and the bushing bolt is accessible to a wrench, but not a lot of room to get a socket on the nut for torquing and stretch. I would think the room would be the same on both sides. Did you have any issues torquing it? The manual say's to remove the X brace but I can't see why that's really necessary.
I need to get under the car and check out the access more closely.

**choppstixxx** · 05-07-2018 03:41 AM

On the passenger side I had no issues getting a 1/2 inch torque wrench with a deep socket in there. Again I had my car up high with the lift tho, you might need a swivel attachment on the socket if it’s at a weird angle on the drivers side.

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**jfo** · 05-07-2018 10:04 AM

Originally Posted by choppstixxx

On the passenger side I had no issues getting a 1/2 inch torque wrench with a deep socket in there. Again I had my car up high with the lift tho, you might need a swivel attachment on the socket if it’s at a weird angle on the drivers side.

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OK, thanks. I'll post back in a few weeks after replacing.

**choppstixxx** · 05-07-2018 11:01 AM

After looking at some pictures online, I believe there is a heat shield on the drivers side as well. Regardless, once you un bolt it and shift it out of the way you should have plenty of room to remove the bolt/get a ratchet in there.

**Spawne32** · 05-07-2018 12:13 PM

those bushings are hydraulic???

**jfo** · 05-07-2018 12:22 PM

Originally Posted by Spawne32

those bushings are hydraulic???

See post 6

**choppstixxx** · 05-07-2018 12:27 PM

I couldn't believe it until I confirmed with my buddy who is an Audi mechanic, guess they started using hydraulic bushings in the B8 series on. There is fluid in the bushing and if it gets pinched or ripped, all the fluid comes out. Gotta replace it or else you'll just slowly wear on other suspension components.

**mtroxel** · 05-13-2018 09:10 AM

I did all 8 front control arms this weekend. My notes:

You no longer have to tip the strut out to remove the upper arm bolts like you did in the B5 through B7’s. Saves some time. One of those bolts on the driver’s side hit a spring, so I just put a jack under the spindle and compressed the spring till it was out of the way.
Ball joint on the curved arms popped right off with a ball joint separator on both sides.
On the lowers, I could not get a triple-square on, or remove, the inside bolt for the front/lower arm with the inner tie rod in the way (see pic). So I removed the two bolts for the steering rack and raised it. Worked great on both sides. I felt like a genius till I spent an hour trying to get the rack to line up with its spot in the sub-frame. Everything is cast aluminum so leave your BFH in the basement.
I had a hydraulic bushing on my 2011’s curved arms. My new ones from Lemforders were still rubber. If there’s a difference, I don’t feel it. But then the whole thing feels more solid with 8 new control arms.
On the curved lower on the pass side, I did not remove that plastic pan behind it. You can get a box wrench in there. But that heat shield had to go before I could get near the other side of that outter bolt on that arm. And I spent about 5 minutes trying to get there with the heat shield laying around above the sub-frame cross brace. Gave up and removed the cross brace to completely remove the shield. I had a long 18mm that got me on the bolt. I have to confess, my torque spec was “good-and-tight”.

**flowhigh** · 05-13-2018 03:32 PM

Not looking forward to doing this down the road. Ugh

**tbroesch** · 08-20-2018 06:47 AM

Does anyone have a preference when it comes to the bushings? ECS has like 5 options for each.

**mtroxel** · 08-20-2018 06:56 AM

I think most guys here just replace the whole arm. I'd hate to put in all that labor to get that arm out, press in a new bushing, then have the ball joint end of that arm fail next spring. Then do it all over again and throw away the new bushing you pressed in 9 months ago....

**elscotto80** · 08-20-2018 08:20 AM

I went with 034's full kit. You may even get a discount and or free gift if you PM thier sales folks through AZ.

Originally Posted by tbroesch

Does anyone have a preference when it comes to the bushings? ECS has like 5 options for each.

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**Spawne32** · 08-20-2018 10:55 AM

i used meyle HD for mine, very high quality stuff

**captain_video** · 08-20-2018 01:04 PM

Originally Posted by mtroxel

I think most guys here just replace the whole arm. I'd hate to put in all that labor to get that arm out, press in a new bushing, then have the ball joint end of that arm fail next spring. Then do it all over again and throw away the new bushing you pressed in 9 months ago....

Amen. I imagine you could also replace the ball joints while doing the bushings, but unless you have your own hydraulic press it will probably end up costing you as much as buying the new arm with the labor involved. Plus there's the down time to consider. I think I'd buy a new set of arms and then look into replacing the bushings and ball joints on the originals to keep as a spare set.

**Archiz** · 08-24-2018 10:59 AM

Also one thing to consider is the diameter of the bush. I replaced my car's curved control arm the past weekend and upgraded from 65mm to 75mm. I believe they will last longer as well.

**cuda2000** · 08-30-2018 05:53 PM

Please forgive my ignorance, what were the symptoms you had to make you find the failed bushings on the control arms? I have a 2010 a4 b8 I have owned since new, now has 80k miles. The steering is not like new anymore. The car follows every groove in the road and seems to wander a little over bumps. I'm assuming ball joints or control arm bushings need to be replaced?

**jfo** · 08-30-2018 07:50 PM

In my case, the bushing failure was obvious since on MY 2011 onward, have a fluid filled bushing on the curved control arm. it was leaking and visible. But I have also been experiencing gradual increase in "tram lining" on certain roads this past year and a feeling that the front suspension/steering is not as tight as it was. I plan to keep the car and don't like to wait until components have totally failed or the driving experience has deteriorated badly, so it's time to refresh the control arms and shocks. It's 7+ years old with about 60K miles...not a lot, but I live in the mountains with salty winters and more wear and tear in general than someone driving on flat, straight freeways.
Other than an obvious tear in a rubber bushing or a very sloppy ball joint, it can be hard to pinpoint a worn control arm visually. They may not have failed outright, but cumulative wear on all those bushings and ball joints( 8 arms in total) will affect performance at some point. The inner and outer tie rods are also subject to wear.
Depending on your driving style and expectations, this may become an issue earlier for some than others.

**mtroxel** · 08-31-2018 04:25 AM

I'm like jfo. I do em all at once. First of all, a complete kit cost less than buying the arms and parts piece-meal. And at your mileage, there is zero chance you're going to replace an arm and the car will be great for another 20,000 miles. How often do you want to jack the car up and remove the front wheels? Buy a kit, do it all at once. Or, do the left front one weekend and the right front the next. They're all going to go. Just do 'em.

**cuda2000** · 08-31-2018 05:27 AM

Sounds like I should do them all at once, I agree. Now I just need to figure if I do it myself or pay a shop. Probably a lot of hours, I'll have my independent audi/vw shop give me an estimate. Thanks for the info!! :)

**Smac770** · 08-31-2018 06:26 AM

I replaced my front dampers and control arms and it cleaned up the car's tracking down the road a lot. My upper control arms actually seemed to be fine, but ball joints on the lowers were shot. My tie rods seemed fine; didn't mess with them.
I used the 034 kit for the front control arms. Not likely the most economical option, but it included everything and worked well.
It's all 16mm and 18mm bolts/nuts, and 21mm nuts on the pins. There is one M12 triple square bolt. And 034 used a 15mm nut for whatever reason for the pinch bolt, so one 15mm too.
You're going to want some longer length torque adapters of 16mm and 18mm; I only have crow feet and it was really annoying to torque the uppers. I got by with a swivel joint on the curved to subframe. Make sure you torque the nuts on the lower arms to subframe, not just the bolt heads.
It's a pretty decent DIY, unless the nut for the curved arm bearing pin gets stuck and the pin starts free spinning and you don't have heat, .... Then hopefully you have a second car and a friendly mech down the road. :-) My pinch bolt was very easy to remove, but I'm not in northern winters or ocean views.