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Herd WebMaster
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USA
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Posted - 05/04/2007 :  07:38:34 AM  Show Profile  Visit Herd WebMaster's Homepage  Reply with Quote
F-car Front Bar
By Scott Mueller.

The absolute best factory front bar for the Impala is the factory 2nd Gen. ('70-'81) F-car (Camaro/Firebird) 32mm front bar (p/n 356534, cost $68.42). This bar came only on cars with the performance Z28 or WS6 suspension, and is available new from GM. In addition to purchasing it new at any GM dealer, you can find this bar used at virtually any auto salvage yard for about $20 or less. Just make sure you get the 32mm bar (not counting the rust ). It directly replaces the stock bar using factory end links and bushings. It is almost exactly the same size and form factor of the stock bar, except it is 2mm thicker and has 1" shorter lever arms. It calculates to be about 35% stiffer than the factory front bar.

To install this bar, you can simply re-use the stock end links which already have urethane bushings, although they are not as good as they should (or could) be. I suggest replacing the stock end link bushings with the much better urethane end link bushings from a 4th gen. F-car. These are available under p/n 10221801 and cost me a whopping $0.68 each, for a total of $5.44 for all 8 that you will need. These have a specially designed recessed cup that retains the large washer and does not allow the bushing to skew sideways or become cocked like the factory bushings. The urethane material also seems to be of a higher grade. I have been retrofitting stock type end links with these killer bushings since they came out in the '93 F-cars!

To mount the bar to the frame, you should replace the stock rubber center clamp bushings with factory 32mm high durometer (hard rubber) bushings that have kevlar liners. The liners prevent wear and friction, and totally eliminate noise as the bar rotates in the bushings. These are available under GM part number 10288551 (32mm) and are for a 4th gen. F-car application. The bushings I just listed have the same basic form factor of the stock bushings (except the larger hole for the larger bar), so the stock brackets (clamps) can be used. The bolts, however should be changed. The original bolts are a metric M10x1.5 30mm prevailing torque bolt. I do not like these bolts at all and absolutely recommend you DO NOT re-use them. The problem is the prevailing torque feature means they have distorted threads that will strip the threads in the frame if installed more than once, as well as making it very difficult to "feel" how tight they are when you are installing them, causing you to easily strip the threads.

If you look at these bolts, you will see that the threads are distorted into a triangular shape, which makes them difficult to insert and remove, and virtually guarantees that you will strip the threads on re-installation. If you strip the threads, you will then be required to install a 3/8" nutsert, which is a device that places a captive nut behind the frame. This is actually much stronger than the stock setup, which has the bolts simply threaded directly into the frame itself with no nut behind! When you see how thin the
threaded area is you will be surprised.

If you want to avoid stripping the stock thread holes, then I recommend replacing the stock bolts with non-prevailing torque bolts of the same size. These will tighten much more easily, and you will know when they are getting too tight. One problem is that the stock bolts are metric and have a very small 10mm hex head to allow for wrench or socket clearance for installation and removal.

If your stock threads in the frame are not stripped, then there are several ways to go for a replacement non-prevailing torque bolt. The factory offers a perfect replacement bolt in a non-prevailing torque version which is even stronger than the original bolts. Part number 15959689 is an M10x1.5-25mm bolt that fits perfectly in place of the stock bolts (4 are required). This is a virtual duplicate of the original bolt, except it is stronger (metric 10.9 grade), and has a slightly larger flange. The head is exactly the same small 10mm hexhead as the stock bolts, and it already has blue loctite applied to the threads!

If you are in a bind, you can probably get M10x1.5 25mm or 30mm standard (non-prevailing torque) thread bolt with a small internal socket hex cap head from the hardware store. Socket head bolts have small cap heads that will easily clear the bracket, and you can use a large (8mm) allen key or allen hex tool to tighten them. Conventional hex head bolts do not leave enough room against the bracket to work properly, and you cannot get a wrench or even a thin wall socket on them easily.

If you want a "show quality" bolt, then you might want to try some hardware from a company called Totally Stainless (800-767-4781). Their motto is "In Stainless we Trust, In Chrome we RUST!" <g> They specialize in nothing but stainless steel fasteners, and have an excellent catalog that every car crafter should have. They have high strength M10x1.5 25mm bolts with hex socket cap heads in pure stainless steel which will never rust or corrode, and which do not feature the distorted threads of the stock bolts. They are available under part number 1-1273 (4 are required). If you call Totally Stainless, tell them I sent you, and get their catalog!

No matter which bolts you use, make sure you apply loctite 242 (blue) to prevent them from loosening (the factory bolts I mentioned already have this), and to act as a lubricant when they are being installed.

In summary, here are the parts needed for the front bar installation:
Qty p/n Description
1 356534 32mm front swaybar, 2nd Gen. ('70-'81) F-car
2 10288551 32mm Bushing, 4th gen. ('93-present) F-car
8 10221801 End link bushings, 4th gen. F-car

plus either one set of the following bolts:

4 15959689 Bolt, M10x1.5-25mm Metric 10.9 grade
4 1-1273* Bolt, M10x1.5-25mm Metric socket head, stainless

* From Totally Stainless

For the ultimate in handling, I also recommend you replace the rear bar with a Herb Adams rear bar. You can get the rear bar from Summit racing (800-230-3030 or 216-630-0200) under the Herb Adams/Moroso name, part number MOR-86516 ('77-up B-car, cost $119).

To install the rear HA swaybar on cars with the 1st design ('77-early '96) rear lower control arms I recommend the following bolts from Totally Stainless:

Qty p/n Description
4 2-0852 7/16"x16 2-3/16" ARP Grade 8 Stainless bolts

If the U-brackets bolted inside your lower control arms are heavily rusted, you will want to purchase new ones. I literally ripped the captive nut right through the original (rusted) brackets on my '88 9C1 during a hard corner, replacing the U-brackets with new parts solved that problem. Then I proceeded to rip the entire U-bracket out of the control arm, shearing off the side bolts in the process. Replacing the side bolts with new high-strength ARP bolts solved that problem, but there is another perhaps better way to solve all of these attachment problems easily and inexpensively. This would be to upgrade to the 2nd style rear lower control arm which has an improved swaybar attachment mechanism. A complete assembly is available from GM under p/n 10289786 (cost only about $40 for the complete kit!) which includes two new lower control arms, plus all of the attaching hardware you'll need to install them, as well as all of the brackets and hardware to install a stock swaybar. You'll then need only to replace the long bolts with new longer ones to install the thicker HA bar.

To install the rear HA swaybar on cars with the 2nd design (mid-'96+) rear lower control arms which uses longer bolts and nuts that go completely through the arm from the top, I recommend the following hardware from GM:
Qty p/n Description
4 11508196 M10x1.5-120mm Grade 10.9 hex flange bolts
4 10255857 M10x1.5 flanged prevailing torque nut

In short, upgrading the swaybars is the single most dramatic improvement you can make. BTW, you should not run the HA rear bar with the stock front bar, and you may even experience a little oversteer in certain situations with the upgraded F-car front bar. Be careful if you push it to the limit, brush up on your countersteering skills.

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