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Discussion Starter · #1 ·
Here it is! After being told by Blau they were out of stock of their rear sway bar kit and might not have stock for several months, I set out on an expedition to build my own kit. Now for the hard part: I can't weld, so this was to be an entirely bolt-on setup.
The car is an early-build 1990 Audi Coupe quattro which did not come equipped with a rear sway bar. The process described will work on 80/90/Coupe quattro up to 92 and probably 4kq and UrQ, depending on tie rod shape. Late build typ89 have the advantage as they already have some of the parts required to do the swap. Here are the results, with a description to follow.





I'll describe everything I went through and give part numbers. A lot of these parts interchange with many, many models so I won't list them all here. If you need to know all the interchange, ask and I'll IM it to you. I'll list the donor car I got them from.
Subframe/sway bar mounts: 895 505 235 D. This is a LATE-BUILD typ89 subframe, from a 92 80Q. The late build is important because this subframe has sway bar mounts already attached from the factory. The 80 did not come with a rear sway, only the late build CQs, and it is very small, measuring I think 14mm. As my original subframe was cracked, replacing it was necessary anyway. This one cost me $26.50 and 2 hours at a junkyard. For additional strength, I had a friend seam-weld the subframe. Just from the way it goes "clunk" when you tap it with a hammer or set it on the ground I can tell it is stiffer. The mount clamps came from the front of the same car: 857 411 335 B quantity 2 and came with the subframe.
Tie Rods: 893 501 499 B quantity 2 from late-build typ 89. I had to buy new ones because the only used ones I could find were shot. $140 each!
My old ones were bent from an accident, so they needed replacing anyway. These are important because the tie rod mount got moved on the subframe with the late-build revision. These allow you to maintain proper toe on the rear wheels.
Sway bar: 857 411 309 D from 85 4kq. This is the front sway bar and measures 26mm. Stiffness of the sway bar increases with the 4th power of the diameter, so this bar is approximately 12 times stiffer than the 14mm bar originally equipped. $6.00 at junkyard.
Control arms: 893 407 147 C (left) and 893 407 148 C (right) from 85 4k FWD. These are the FRONT arms of that car. These arms are important because they will accept the 2-bolt sliding rear ball joints AND have a receptacle for the end link bushings. As the rear suspension of these quattro models is identical in geometry to the front, these are directly interchangeable. $12.50 each at junkyard.
End links: 855 407 469 quantity 2 from 90 FWD. These have the proper angle to clear the rear halfshafts and also prevent interference between the rear tie rods and sway bar. As I recall I "borrowed" these from the junkyard.

Bushings: all purchased new, 2 of each part number. Mount bushings 811 411 327 B, sway bar end bushings 857 407 473 A, metal sleeve 857 407 479 A, end link bushings 857 407 474, metal sleeve 857 407 480. Total cost was around $40 IIRC. You need 8 curved washers 857 407 477A and these are plentiful in the junkyard. Other hardware you'll need: 4 M8x20mm bolts for mounts, 4 M8x1.25 nuts for end links, and I recommend green penetrating loctite on the fasteners. It has a low break strength but a very high prevailing strength, which I think is ideal for suspension, plus it can be applied after assembly.
In addition I replaced control arm bushings, subframe bushings, and rear diff mounts. Other services performed: I sandblasted all of it, and it got powdercoated with 20% gloss black. The little parts got painted with Rustoleum exterior satin enamel which matches the powdercoating perfectly. There's no point in putting all this effort into the car if the stuff is going to rust in a few years!!
Installation: Bolt it together!! Drop the entire rear end at once. Transfer the rear diff to the new subframe and re-install. Then build the suspension around that. It helps to leave the control arms connected to the strut and loose at the subframe to mount the end links. End link bushings should be pressed in with a touch of lube on them to let them slide easier. Pressing those in was the most difficult part of the project.
Misc comments: Clearance is closest at full droop. I have .020" clearance between the tie rods and sway bar. Yes, thats right, 20 thousandths. I had to use the feeler gauge to measure. For reference, I couldn't fit a paper towel in this space. As the suspension compresses, they move away from each other. Properly centering the sway bar is crucial to avoiding clearance issues. Also, there is about 1/4" clearance between the sway bar and driveshafts, but this also increases as the suspension compresses. Rear spindles and ball joints are the OEM-specified piece for my car. No need to swap them. Ball joints were still in great shape so I am re-using them.
If you were to use all used components (I tried) you could get into this setup for around $120, including bushings/hardware. As I had to lay out $280 on tie rods, mine was more expensive than that, but my whole suspension is new and I'm in less than $500 including powdercoating.
Questions - feel free to post them up!!
[edit] Fixed broken URLs on pics... AGAIN


Modified by billzcat1 at 2:23 PM 2-21-2005
 

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Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (billzcat1)

WOW! Very impressive, where were you at with this stuff when I had my cq??
So exactly how close is the endlinks to the axles? They won't touch if everything flexes under a load? Looks great, I was wondering how you got everthing so clean. How bad was the car wrecked?
 

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Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (billzcat1)

Looks very nice, but for the most of us, it requires welding. The reason that your new rear frame had the mounts on your car is that many B4s had rear sway bar as stock equipment.
 

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Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (PerL)

That doesn't look anything like the underside of mine.....where's the rust, the crud, the dings??? - it's wayyyy to clean
. Nice job, now all you've got to do is get it off those stands and onto the pavement.
Non-sway bar question, on that shot looking up the center drive line, is that the proper angle for the shaft? bent to the right around the center bearing or is the motor and tranny out and the shaft is de-coupled??
 

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Discussion Starter · #5 ·
Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (blkaudicq)

The endlinks are right about 1/4" from the axle but its hard to get a picture to show the clearance. As the suspension travels upward, everything gains more clearance. I should set it down on the wheels and try to show the clearance under load. The car wasn't wrecked badly at all, but the impact was directly on the passenger side rear wheel. The old subframe had very small stress cracks from a bad rear diff mount clunking for a couple years (just never got to it) and the impact sealed the deal with a large crack and bent subframe, bent control arm, bent tie rods, a shattered bumper, broken Treser taillight, and a little sheet metal damage. The loss of the Treser was most maddening, but I found another one overseas and it got delivered Wednesday!
As for welding - not required if you are going to swap subframes. This is not a B4 subframe - those have totally different mount setups and a different rear differential, requiring a different center driveshaft. This subframe is for the late-build revision on the typ89 which is I think in late 1990.
As for your non-sway bar question: NO that's not the proper driveshaft angle. It is supposed to be perfectly straight back, both vertically and horizontally. There is an alignment tool you are supposed to use along with spacers. A friend of mine made the tool; I'll be borrowing it. Also note the passenger side rear half-shaft is disconnected at the inner CV. My favorite torque wrench broke and wouldn't click so I broke a bolt off in the output flange

Why is it still crooked?
I haven't mounted the motor yet, and I had to remake one of the transmission mount spacers (not thick enough the first time around). As of this shot, the transmission and engine are bolted together, but only have one mount and are suspended by the engine hoist (see pic).
When I mount the motor (requiring custom mounts, no 20vt swap for me
) I'll be aligning the driveshaft and ensuring subframe/oil pan clearance at the same time. As for the no-weld technique: I'm afraid I can't continue that on the mounts. I can make all the braces and I'll have a friend do the welding.



Modified by billzcat1 at 1:16 PM 2-16-2004
 

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Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (billzcat1)

I dont know if richard wrote this before but im guessing this mod isnt possible on a 90 20v sedan? or are there any other options that one could take. Looks clean rich.
 

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Discussion Starter · #7 ·
Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (Squanttro)

Quote, originally posted by Squanttro »
im guessing this mod isnt possible on a 90 20v sedan?

Quote, originally posted by billzcat1 »
The process described will work on 80/90/Coupe quattro up to 92
 

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Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (billzcat1)

If you don't mind me asking kind of a newb question, how does this setup differ from an '84 4KQ?
 

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Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro ([email protected])

wait im confused....my 87q rear subframe is the smae..i figured that out...now where did oyu egt the stress abr from then...waht car i mean...or is it just front the front subframe
 

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Discussion Starter · #10 ·
Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (glibobbo21)

George: the rear of the 4kq uses a one piece strut and inverted ball joint. I am not sure if the 4kq front control arms can accept the inverted ball joint. Also, the tie rods are of different shape (still might be compatible) and the pitman arms on the knuckle are a bit different.
Otherwise, the subframe itself is basically the same with slightly different tie rod mounts and the addition of the sway bar mount locations. This should answer your question Glibobbo - the sway bar and tie rod mounts are different from your 87 rear subframe.
The sway bar is the front 4000 quattro unit. The subframe is a late-build 80 quattro rear subframe. The front subframe cannot be swapped to the rear without adding the center mount for the rear diff and the tabs for hand brake cables. Otherwise the front would be interchangeable.
 

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Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (billzcat1)

hmmmmmmmmmmmmm nasty ideas in my head for the golf...since the rear subframe is in now
http://****************.com/smile/emthup.gif
it would be interesting to know if the mounting point on the subframe itself are the same as the 400 cuz id love to have 2 peice strut setups for camber


Modified by glibobbo21 at 1:47 PM 2-17-2004
 

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Discussion Starter · #12 ·
Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (glibobbo21)

yes, the subframe-body mounting points are the same for front and rear subframes for all 4lq, 88-92 80q/90q/Coupe-q, and Ur-Quattro. The suspension geometry didn't really change for these models, just a few variations and revisions.
I'd say go for it - pick up an extra set of front control arms and see if they are swappable to the rear. I don't recall offhand how the inverted ball joints mount in the rear control arms of the 4kq. Converting the whole suspension to a 2-piece strut would solve this, but that's an extensive project and it might get expensive. Luckily we are blessed with a few inexpensive junkyards in this area.
Most of the camber adjust is done in the control arm, where the ball joint slides in an out. There is very limited adjustment in the strut/knuckle connection. The 4000 stuff is much stronger if you are rallying, but the 2-piece units are much lighter.
 

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Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (billzcat1)

hmmm...interesting
i was looking at mine this morning and pondering if itd work and it looks it

there shouldnt be anything in the way, maybe ill try to find a front stress abr and see what i can do, but im more worried about finishing up the mounts right now http://****************.com/smile/emthup.gif
see the sig if you want more pics fo the golf
 

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Discussion Starter · #14 ·
Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (glibobbo21)

Looks good, you'll just need to make the sway bar mounts, but that shouldn't be a problem for you
I'm sure your skills at fabricating are much greater than mine. You can see in that picture the slight difference in the tie rod mounts. I think that your straight tie rods will allow for more sway bar clearance. Check the rear control arms. Make sure the slot for the ball joints is similar to the front. Thats basically all you need to know!
Good luck
 

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Discussion Starter · #16 ·
Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (glibobbo21)

The listed replacement is the same P/N, (supercession) so I'm sure they will interchange correctly. Your stock rears (original) may not have the sway bar end link receptacles. I know mine did not, although a replacement one would.
 

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Discussion Starter · #19 ·
Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (tonydule)

Indeed that was my inspiration - but with no fabricating skill to speak of I went for a bolt-on option. My original rear control arms didn't have the receptacle for the sway bar and the subframe swap put the mounts on there for me.
 

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Discussion Starter · #20 ·
Re: Rear Sway Bar for Coupe, 80/90, 4000, Ur-quattro (billzcat1)

This just in: had the car up on a trailer and thought it would be the perfect opportunity to snap some shots of the sway bar at a normal amount of suspension travel. This is at max lift on the coilovers, and as the car goes down/suspension goes up, the distance between sway bar and tie rod keeps increasing.

Just like I said - lots of room once the suspension is compressed. The end link is also away from the half-shaft a little more but I couldn't get a good angle to shoot it with the wheel attached.
[EDIT] FIXED ANOTHER BROKEN URL TO PIC



Modified by billzcat1 at 2:24 PM 2-21-2005
 
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