Question regarding the AVO Rear Stabilizer Mount Brace

About a month ago I installed the AVO rear stabilizer mount braces as part of my car's mid-life suspension refresh (2008 2.5i Sedan).

 

During the install it dawned on me that the braces actually lock the rear subframe in place: the braces attach to the subframe (via the stabilizer bar mounts) and then bolt onto the rear chassis-to-subframe mounting points thereby locking it to the chassis. Am I mistaken about this?

 

Assuming this is the case, has this caused any issues for those of you who take your vehicles mild off-roading once in a while? (Bumpy forest service roads, gravel roads, etc)

 

BTW, the difference in handling by just installing the AVO braces was huge. The rear end of the car is so much more predictable on curvy highway sections. And, this is with the stock 15mm rear sway bar. In fact, the improvement is so pronounced that I just might call it "good enough" and live with the skinny 15mm sway bar.

The rear sway bar mounts are all part of the subframe...so the AVO brackets are just adding another bracing point for the swaybar. There is not locking of two independent parts happening with the addition of the brace. The point of it is because the swaybar mounts are flimsy and not supported very well for how cantilevered they are off the subframe.

That's true for the two points where the AVO brace mounts to the flimsy swaybar mounts. But the third mounting point, the cylindrical section, mounts using the same bolt that appears to mount the subframe to the chassis.

 

 

Have a look at the photos in this thread:

 

 

https://legacygt.com/forums/showthread.php/did-install-my-avo-sway-bar-brackets-correctlyi-147933.html

 

 

The large mounting bolt in the first picture clamps the cup/stop (the part that was inverted in that thread) and the AVO brrace to the center sleeve of the rubber isolation bushing to the chassis. So we are essentially nullifying the effects of that rubber bushing which probably explains the large improvement in rear end stability I'm experiencing despite not (yet) changing the rear swaybar.

Edited February 21, 2020 by dk1604

The addition of the braces make little difference to the mount isolation. The subframe can still move as intended, but the bracing just keeps the sway bar properly in place. The sway bar works based on twisting, not so much the flex of the mount. Edited February 21, 2020 by Chocoholic005

I guess I'm missing something. To me, it seems the cylindrical mount of the AVO brace is securely fixed to the chassis by the large bolt: (1) in the diagram. At the same time, the AVO brace is securely attached to the subframe via the sway bar mounts: [A] in the diagram. I just don't see how the subframe can move freely after that.

you're right. in a very small amount, it holds the subframe in place through the sway bar mount, but in actual function the front of the subframe will still be able to shift and pitch, and the bushings in the subframe are solid rubber --- they're more there for vibration dampening than actual function of shifting.

 

I wouldn't consider it a problem by any means.

The original sway bar mount flexes much more than the subframe mount moves. Your assessment of how things are connected is correct.

I’m thinking that the subframe isolation is for nvh more than anything else so even though you’re essentially fixing 2 points to the chassis all you may be doing is adding some nvh and remoing some play between suspension and chassis. Stiffening up the mounts may be why you feel a difference more than fastening the back of the subframe to the chassis. Or maybe its a combination of both.

Thanks for your comments everyone. I was just amazed at how much of a difference it made so it definitely eliminated some flex somewhere. I'm very happy with the result but was worried about what might happen when I take the car on some rougher roads. It's good to know that nobody seems to have had any problems.

 

Of all of the things that I've done so far in the car's mid-life suspension refresh: new KYB struts on all corners, new sway bar end-links on all corners, new sway bar bushings on all corners (new oem rubber in the front, polyurethane in the back), new aluminum front control arms with the solid mevotech rear bushing, installation of a strut tower brace; the AVO braces probably had the most noticeable effect on the precision of how the car handles through curves (on Highway 99, Vancouver to Squamish and back). Before that it was hard to "feel" the curves and the rear would seem to wander. The tail still feels like it sticks out a bit in curves at higher speeds but it's much more predictable and consistent. (Would a thicker rear sway bar help with that?) I suppose it's possible that the AVO braces were the last piece of the puzzle needed to get the car's suspension back to a respectable state and that's why it felt so dramatically better.

 

BTW, the rubber subframe bushings on my 2008 2.5i are actually similar to to the OE rear bushing on our front control arms in that they have voids in them. They looked OK but I do wonder how much they have softened up with age. I purchased the car used (with about 60,000 miles on her; now she has about 130,000 miles) so I never experienced how the car handled when new.

Edited February 23, 2020 by dk1604

You should get a beefier rear sway bar if you feel like the AVO mounts made a nice difference. Even a JDM rear sway bar upgrade makes a HUGE difference in cornering, especially if you've already done all the mounts, bushings and links. No negative consequence whatsoever either in my opinion.

I felt the 20mm rear sway made a huge difference. On a really hard corner I could feel the rear of the body rolling but not the front and it was a weird and uncomfortable feeling. New rear links and 20mm rear whiteline sway bar on the "soft" setting makes the rear of the outback feel like the front of the outback. And that was the only suspension change I've done so far.

Thanks all. Definitely can relate to that weird and uncomfortable feeling in the curves and that's what motivated me to do the suspension refresh.

 

I've been keeping an eye out on ebay for JDM rear sway bars. That and KTA124 are really the only things left on my original to do list.

The avo brackets are probably compressing the rear bushing a bit and thus functioning as void filling inserts.

 

Though with the tube design ones, for our cars, it shouldn't be too bad:

https://avoturbo.com/suspension-body-brace-liberty-2-5i-ej253-s1104m1ht001t/

 

I can see these doing a lot more compressing though:

https://avoturbo.com/suspension-body-brace-outback-2-5i-ej253-s2c08g1ht002t/

 

 

Also traildogck mentioned the same with the more flat design (perhaps that was the first version of AVO ones for our cars?

I felt the 20mm rear sway made a huge difference. On a really hard corner I could feel the rear of the body rolling but not the front and it was a weird and uncomfortable feeling. New rear links and 20mm rear whiteline sway bar on the "soft" setting makes the rear of the outback feel like the front of the outback. And that was the only suspension change I've done so far.

 

Nonamedude, I forgot to ask earlier, did you install the AVO braces along with the 20mm rear sway bar? Or, are you running only the 20mm bar on the stock mounts?

Interesting, I didn't even realize there were other options for sway bar braces for our cars.

 

The AVO braces shouldn't be compressing the rubber mounts. Well, at least not anymore than they were originally. The bushing setup is exactly the same as the rear bushing on our front control arms (20204AG011). Their overall diameter is smaller but it appears to be the same inner sleeve, rubber with voids, outer sleeve arrangement. The AVO brackets mount to the bushing's inner sleeve and bump stop (20176) with bolt (1). Bolt (1) then gets torqued to the factory spec of 129ft-lbs so it's not compressed anymore than it was before.

 

I have been thinking about alternate ways of reinforcing the mounts without restricting the motion of the subframe but the car is so much more pleasurable to drive with the AVO braces. (And that's with snow tires installed! Really looking forward to getting back onto the all-seasons.)

No reinforcements. I hadn't realized they were a thing when buying parts. Kart boy end links.

 

 

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In my opinion, if you are willing to live with extra NVH, there is no problems with restricting the subframe motion/slop...

 

Having slop in the subframe adds to camber loss and changing toe during a turn, which leads to instability and loss of traction. Thus there are ton of fully solid subframe mods (from aluminum to poly) out there for other cars and those cars are still safe/fine. Heck I'm going to do that on my G20 here in the near future, but with the front subframe.

 

I think what traildogck was referring to is, having only the rear be "solid" and the front be stock. But at the same time I'm not sure I agree that it would cause any issues, having even the rear be "solid" would compensate for the front's slop and net overall gain, like you saw .

The #1 goal of the brackets is to reinforce the actual rear sway bar mounting tabs, just to be clear.

 

With a bigger bar and solid endlinks that tab can snap as a result of the extra force compared to the flexible OEM links and spaghetti noodle sway bar. Doesn't matter your path, but the benefits of the brackets should be minimal compared to the primary parts being upgraded.

Thanks for this thread. AVO bracket reinforcement does lock up sub frame isolation. Just purchased the AVO bar but made my own reinforcement brackets. AVO bar paint is dissapointing - ended up clear coating the bar with Spray max 368 0061. Too bad my pics fail to upload (less than 6mb and 6400x6400)

Presentation1.pdf

Edited February 17, 2022 by mjtct

Thanks for this thread. AVO bracket reinforcement does lock up sub frame isolation. Just purchased the AVO bar but made my own reinforcement brackets. AVO bar paint is dissapointing - ended up clear coating the bar with Spray max 368 0061. Too bad my pics fail to upload (less than 6mb and 6400x6400)

 

 

Thanks! Please let us know what your impressions are of your new sway bar on a non-locked sub frame. FWIW, I'm still running the AVO braces with a 19mm JDM sway bar, but I did the braces first and then the sway bar. Each made a noticeable improvement but I'm curious how much an improvement just the bar would have made.

Anybody know the specs for the longer bolts that came with the brace kit? I need another set of bolts

It's been a few years now that my memory of the installation is a bit foggy.  I may very well be mistaken but I don't think the braces came with additional bolts and I just reused the factory bolts.  I've attached the instructions and from what I recall, what is pictured is what came in the kit.

Hopefully someone with better recollection can chime in.

S1303G1HT001T.pdf

These braces sorry https://avoturbo.com/rear-underbody-support-brace-subaru-liberty-gt-spec-outback

I have the avo sway bar reinforcement and avo rear sway bar

Edited March 31 by Shawn16

11 hours ago, Shawn16 said:

These braces sorry https://avoturbo.com/rear-underbody-support-brace-subaru-liberty-gt-spec-outback

I have the avo sway bar reinforcement and avo rear sway bar

Those bolts are 8.8 approx 4" long and 12mm or .46" in diameter. Thread pitch doesn't really matter, just need to match the nut.