Shocks and Sway Bars
by Richard Atwell
Are you curious about sway bars? Do they cure wind buffeting? How hard are they to install? Why aren't they called anti-sway bars? I recently finished my installation and if you follow my journey recorded below you may find something that works for you as well as it did for me.
Disclaimer: modifying the suspension of your bus will alter the handling and influence your ability to control it. Whether you are replacing shocks or adding sway bars, always follow common sense practices and use caution when you drive.
Before you stiffen your suspension with "sway bars", you need to upgrade your shocks if they are clapped out. You'll never achieve great handling in a bus without good shocks.
Many folks who get bus fever buy some old bus with worn out shocks and complain about the handling on the highway right away. Keep in mind that the original oil filled shocks weren't designed to last forever. When the bus keels over and won't to spring back it's because the shocks are offering too little resistance to that motion. If the bus has been sitting in one position for several years the shocks can fail as quickly as the first drive. I recommend removing all 5 (including the steering damper) and testing their worthiness by hand. If the shock gurgles badly on extension and/or compresses without resistance it's shot and will require replacement.
There is often confusion whether or not new shocks will raise a sagging rear end. This arises because gas shocks will extend on their own when unmounted but oil filled shocks will hold their position. The result seen at the rear simply depends on the which technology is used.
What most bus owners don't realize is that it's the gas shocks mounted on the front that is pushing up the front giving the impression that the rear is sagging more than it really is. VW never sold a bus with gas shocks: they were always oil filled and when you switch from the stock Boge shocks you'd better be using Koni or Bilstein which were designed for the bus (in order words backed by research dollars instead of marketing dollars).
If the end of your bus is sagging so much that the extra little push from a gas shock levels the bus you really need to correct the spring plate angle by adjusting the torsion bars. This isn't as hard as it seems and it's quite necessary to keep the suspension within spec. Unless you measure the spring plate angle you'll never be able to determine whether adjustment is necessary with gas shocks on the front of your bus "eyeballing it" because of their influence of the ride height.
Remember that the torsion bar is the part of the suspension that provides the spring for the ride. Shocks only damp the spring motion (they absorb the bounce and attempt to eliminate it). The need to set the torsion bars correctly is to allow the suspension to travel about a predetermined center. When the bars "wears" and require adjustment you are resetting the spring rate for the rear end. Without it the altered spring rate of the vehicle will result in a bouncy ride.
Another important issue is that there is a limited amount of force that the original shock mounts can endure: the lower one is sturdy but the top one tends to weaken because of wheel well corrosion. A big mistake is to replace the rear shocks with coil-overs. Although VW offered a HD coil-over shock under some m-code, I've never seen one (came close once) or met anyone that's seen one. It's possible that the brand used may have been Load Leveler but I can't verify this either. Given no VW approved coil-over is available, bus owners use coil-overs designed for other US vehicles. Half of the time the extra force of the spring breaks off the top shock mount to the regret of the owner so be keep that in mind.
The original Fitchel & Sachs (Boge) shocks and replacement German/Mexican Boges are too soft in the opinion of many people. Although the ride is smooth and largely bump free on rough roads, it's also spongy sometimes with excess body roll and the front end of the bus tends to float a bit (think large Cadillac land yacht cruising down the interstate).
I believe a lot of this sentiment comes from old shocks. I've driven in a 47k mile one owner bus with the original shocks and I simply loved the ride. The bus was never meant to handle like a Honda but there's a mix of charm and practicality to it. If you want the original ride, oil filled Boges are the shocks to use. Get them from Bus Depot because they are the only ones importing them from Germany. Everyone else gets the from the Boge/Sachs USA who import them from the Mexican factory.
Turning corners with oil filled shocks in the bus with its high center of gravity and tall sidewall tires is no fun sometimes. Now, VW engineers weren't dummies so they equipped the bus with the appropriate shocks whether you were driving alone or carrying 9 people or your family and all of your camping gear. I've always marveled at how evenly the bus rides so nice no matter how loaded down it is with cargo/people. A tribute to the original commercial design.
Except for those with sagging rear ends who mistakenly decide to go to a coil-over shock setup, often the damper of choice for the bus is the Japanese KYB gas shock. This is not because KYB makes a particularly good shock: it's because they are one of the few companies still making 68-79 bus shocks.
KYB makes two types for our busses: GR-2 Gas Rider (silver cartridge), and the Gas-a-Just (white cartridge).
Looking at the numbers you can see that KYB supplies one shock for all 55-79 bus models!
Comparing the suspensions of all generations of VW buses revels that they are very different from each other. At a basic level, the weight of each generation varies greatly so putting split shocks on the baywindow doesn't make sense to me.
There are also physical difference to consider: the 68-79 baywindow bus has unique front shock requirements (just check the fiche). The rears differ because the 68-79 bus shock is much longer than the split window rear shock with its reduction box rear end. If you search on those part numbers you'll find the front Gas-a-Justs fit the front of the beetle and the front GR-2s fit the REAR of the beetle. These shocks are a compromise to limit the models produced to fit as many VW models as possible. In other words, they aren't ideal for any VW model, especially the bus.
I used to have Gas-a-Justs front and rear (taking advice from Bus Depot) because the handling was supposed to be far improved over using oil filled shocks. However, I didn't heed the other warning from Bus Depot:
They ride a bit stiffer than stock (not quite as smooth over bumps), but noticeably improve cornering, handling and wind buffeting.
Although the handling was improved, I could feel every bump in the road and it was unpleasant.
Taking a tip from Type2 list members I went with the Vanagon Setup recommended for KYBs: GR-2 on front, Gas-a-Just on rear. Although I could still feel the stiff shocks on the rear from the front seat this combination at the time made more sense than using GR-2 for all 4 shocks which were derided as being too soft. However, this kind of mixing and matching only messes up your handling and braking even more.
The GR-2 front shocks are nice (just firm enough) but you loose a lot of the handling in the form of body roll compared to the Gas-a-Justs on the front. I don't see the value in the GR-2 shocks over oil filled Boges because they ride harder than oil filled shocks but don't offer substantially better handling.
Recently Bus Depot started to sell RV shocks from Alko Suspension. They are oil filled shocks from Europe but I don't know enough about them at this time. The owner is a true bus person and typically only buys products that he would put on his own bus. If you have experience with these shocks I'd like to hear from you.
Unfortunately, Koni and Bilstein no longer makes shocks for the 68-79 baywindow bus. If you've ever driven a car with Bilsteins it's a wonderful experience. They are premium gas shocks which offer a smooth ride and improved handling and are auto-adjusting for wear. Koni's adjustable oil filled shocks (Red specials) are even better because they solve the problem with non adjustable shocks being too soft or too stiff. You can read more about both of here on my Koni webpage. In many cases you can have those shocks rebuilt by either company as long as they still have the damping specs because the parts they use are shared between many models which largely differ in length, style, eye bolt size, spacer sleeve length etc.
Despite being called Gas-a-Justs KYBs are NOT adjustable: it's only a marketing gimmick.
After restoring the quality of your ride, you need to deal with sway bars if you want to improve the suspension further. Although there are many methods used in combination to fine tune a suspension, the bus wasn't designed as a performance vehicle and so a limited number of replacement suspension parts exist and sway bars are the most popular.
Since a sway bar only resists twisting (its basically a contoured torsion bar), any up down motion experienced by both sides of the suspension is not influenced by the sway bar. This means you can keep the ride quality while improving the handling but there are still a few compromises in store.
|Front Swaybar||Rear Swaybar|
The first choice is deciding what brand to get and where to get parts. I went with Sway-A-Way (SAW) because I know they make good stuff and I heard they had the best design for a non-adjustable bar. SAW doesn't sell to the public so you have to get it from somewhere else. If you can buy them locally (BugPack dealer), do so because the package is oversized and UPS is going to hit you up for the oversize fee.
The SAW kit included bushings and hardware for the rear, but only bushings for the front (you have to re-use the stock clamps or buy new ones - see the next section for details).
The other brand is I know of is EMPI. The front part number is 9611 and the rear is 9610. Again, like SAW, they don't sell to the public so get them from Bus Boys. I don't know much about their hardware kits except that the rear sway bar attaches to the lower shock mount instead of the wheel bearing housing.
One other thing to note about the EMPI rear design is that it hangs a lot lower in the center than the SAW design as seen in the burned engine photo on the left. I don't know exactly what problem this will cause for people that like to go off-road on occasion but it's something to consider because I've heard it's an issue. You can see my SAW rear sway bar in the right photo to see just how low the EMPI bar is mounted:
|Look under the transmission||My Rear Swaybar (since removed)|
Aircooled.net offers both non-adjustable and adjustable bars. I know nothing about them except that they are the Whiteline brand.
Here are some photos of a Whiteline installation (dead link) on a baywindow bus. The sway bars look good but I'm not too impressed by the style of the mounting hardware.
I recently learned from SAW that their kit wasn't a big mover so they've discontinued it. All that's left is the stock on hand at various resellers so if you want this brand and you can get a good price get it otherwise get the Whitelines from ACN. Another reason I've heard that the SAW kit is no longer available is that vendors stopped selling them because of returns having to do with defects and problems with the cadmium plating. I heard this from one of the bus vendors and have no verification of it but apparently the bars made two years earlier didn't have this problem.
If you get the bars from another bus and the bushings are worn out you're going to have equal difficulty finding those. The reason is that BugPack/Prothane are discontinuing their hardware and bushings kits, again because of lack of demand. This is too bad. I personally think the problem was price: the kits were too expensive in addition to the bars and the benefits weren't well advertised. CIP1 seemed to be the last vendor to offer this rear sway bar mounting kit for $60.
Bus suspension modifications and aftermarket parts: a lethal combination that can result in a lot of cursing. Hopefully reading this article will save you from the grief that I went through. I bet 914 folks don't have this problem but then again, Porsche parts mean Porsche prices. Before working on the bus, put it up on ramps to give you more working room.
The stock bar is held on by clamps that wrap around the front lower torsion arms and squeeze the bushings holding the sway bar against the torsion arm. These clamps can be a bugger to get off because of all the grease in that general area and because the securing tab rusts to the clamp. Try to get it off but if you can't you might want to cut off the securing tab on the bottom. You do not want to damage the clamp trying to remove it in case you want to re-use them. If you are buying new clamps anyway then hack away! If you cut the securing tab, you need to buy the entire kit because the tab is not sold separately.
There are three styles of front mounting hardware available:
The stock clamp was still available at the time of writing for about $18 but getting increasingly hard to find. The reproduction clamp costs $3 each ($6 for a pair) and the T-bolt clamps vary in price according to size and width. I've seen them at Aircooled.net for $30.
I made the mistake of buying the cheapest of the three (Brazil) and I got burned. Look for the NOS German or Mexican clamps. I tried without success to get the Brazil clamps on but failed miserably. The reason wasn't obvious until I compared them to the original clamps: the profile at the top is different and you'll never get them to meet at the bottom. The reason for this is that the Brazilian bus sway bar is slightly smaller than the German one and the torsion arm is slightly different (king pin front end).
You will have to alter the shape of that clamp to make it work. I didn't have the tools or patience to do this: the Brazil clamp is also made from a thicker metal which makes it that much more difficult to bend.
The Brazil clamps tend to be coated with yellow chromate which gives them away. For $3 you get a clamp, a securing tab, a new bushing and a nut/bolt/washer. The bushing is rubber and only fits the stock bar unless you bore it out. Don't bother with it: just get urethane bushings as they last longer than rubber and I've never heard them squeak which is an often stated complaint. The bolt in the kit is grade 5.8 which is weaker than what came off the bus. You may want to get a better bolt at your favorite fastener supplier if you attempt to use any of the items in this kit. Basically, the kit is only useful for it's securing tab.
The NOS kit is Genuine so there's not much wrong with it except that the clamps are only hard to install instead of impossible. The trick to installing them is all in the preparation. If you are reusing the old clamps, clean them first. If you have heavy rust corrosion on the inner walls, smooth it or replace the clamps. After they are clean, file or Dremel the surface that will mate with the securing tab and then grease the same area to ease installation.
Before securing the clamps, install the bushings on the front sway bar. The urethane bushings come with a grease lubricant to prevent squeaking which is made from a mixture of teflon and vaseline. Even though the bushing kits come with the grease I've been told by JC at Aircooled.net not to apply it to the front sway bars. I couldn't get the reason for this ouf of him so I applied a little anyway and it's been no problem since.
Bolt up the front bar and torque to 25-36 ft. lbs. Widen the clamp so it can fit over the lower torsion arm and the bushing and then use a pair of wide jawed pliers like channel locks to close them as much as possible at the front by pinching at the lowest point. With a pair of vise-grips lock the clamp in the near closed position at the back. Release the front pliers, and re-apply pressure with them again while you try to fit the securing tab. The tab faces rearward. Don't accidentally put the bushing on the wrong way: the fat end goes towards the front.
Once the tab is started you can hammer it all the way on and bend the tab up at the rear to secure it. Wipe away any excess grease and repeat for the other side.
Like the 4 1/2" stainless steel (SS) T-bolt clamps used on the rear pictured above, they are also available for the front but I was unable to obtain any in time before an important trip. These are not special sway bar clamps but instead really tough clamps used for a multitude of fastening applications. I know of several companies that make them: Clamp Co. and Five Star Mfg. have websites but neither of these companies sell to the public and I'm sure the SS sway bar clamp kits are indirectly sourced from these suppliers.
I recently found out that NAPA stocks t-bolt clamps under the Balkamp brand (another big clamp supplier) for about $3 each. Ideal and Breeze Clamp also sell T-bolt clamps so you might get those in your NAPA order. You'll need clamps that open to 2 1/2" in diameter for the front sway bar.
At first I couldn't imagine how to use these clamps because the bushing is a trapezoidal shape and the stock clamp is this shape also. The clamp is going to want grip an object with parallel sides. It turns out that you need to use two clamps per bushing. I'm not sure how this deforms the bushing but since the clamps are very strong they are probably the way to go especially if you plan to remove your front lower torsion arms or change your sway bar in future with ease.
If you see these clamps at your local VW flaps they could be for a link pin beetle suspension and they are too small to use on the bus. I suspect the ball joint beetle version is also too small but I've never seen them to prove it.
SAW-8500 is the part number for the bus clamps Sway-a-Way used to sell (they've now obsoleted the part). I tried to order some from McKenzie's but gave up trying because they didn't have the part number in their system anymore (it was only an artifact on their webpage). I called SAW and they said they had them but I'd have to get them through Mckenzie's. Catch 22! Don't you love it? They were about $9 a clamp according to SAW (requiring 4) and but I never got to see them.
I suspect you could find your own at NAPA for $5 each if you knew the diameter. I also checked the McMaster-Carr catalog (Hose Clamps, page 207) but none of their clamps are wide enough.
The hardest part about the front installation is securing the clamps with one a pair of hands. The hardest part about the rear installation is the fact that the hardware kit I used was inadequate. Maybe you'll have better luck with another brand like Whiteline.
Problem #1: the bracket won't lie flat against the wheel bearing housing because there is a round recess for the M14 bolt. The picture above is of a bracket I found at the junkyard and it was deformed. At first I thought it was due to stress from the sway bar but once I removed it I knew why. The bracket needs to be offset using a M14 or 9/16" lock washer. If you don't use a grippy lock washer then the bracket will rotate as you try to tighten the bolt and the bracket won't align with the sway bar.
Problem #2: may or my not happen to you: the threads on the bolt have been sheared away by the spring plate. On top of that it's a 10.9 grade bolt without any coating so weather has rusted the threads. Finding a M14x1.5 35mm locally can be a struggle. If you see a bolt like this, be a little worried about the other bolts on the spring plate. For the same reason, you should have new fasteners of the correct grade and length ready before you plan to reset the spring plate on your rear torsion bars.
Problem #3: I was simply going to remove the bolt when I realized that with the washer and bracket in place the bolt won't be long enough to thread into the wheel bearing housing from the diagonal arm. Buy a 45mm bolt instead. It's a little longer but it's a popular size and I couldn't find 40mm from my fastener guy (they did a special order from the Bossard Metric catalog). The bracket in the middle photos actually mounts the other way around. I just took the picture that way while concentrating on the lengths and later realized that I'd taken it backwards.
Problem #4: the washers the hardware kit provided for the ends of the sway bar didn't fit over the non threaded part of the bolt. I had to drill the bottom two washers slightly.
Problem #5: take a look at the junkyard bracket again. Notice the corner has been cut away. It's because it hits the cv joint if you don't clearance it.
It's simply amazing what a lousy kit this was and they've been making it this way for years as I understand. No wonder sales were low and it was discontinued!
Bolting up the rear bar isn't that tricky. Start by securing the bar to the rear torsion tubes with the T-bolt clamps but don't tighten fully. You only want to figure out what angle to orient the brackets on the wheel bearing housing. Once you figure that out you can torque the bolts to 94 ft. lbs. and secure the bar by tightening the t-bolt clamps. Torquing up the bracket without rotating it is the tricky part. Finally, be sure to apply the Prothane grease between the urethane bushing and the bar so the bar can rotate freely as the suspension moves.
Do not over tighten the bushings. You want them firm and in place but do not squeeze them too much or they won't be able to compress as the suspension travels. This is very important for the little ones at the ends because that will force them to crack.
I received various handling reports from other people with sway bars installed before I installed them. Some said upgrade just the front bar and some said both. There is a lot of advice on the web about only upgrading the bars in pairs especially on IRS VWs but I think this advice largely comes from the community of other car clubs where neither a front or rear bar exist on the stock vehicle. Therefore I decided to gather my own results during 4 test drives:
Unfortunately, I misplaced the results from the second test (*) and cannot recall them.
The bus has a 43/57 rearward weight distribution with the driver on board. I obtained this measurement from a drive-thru weigh scale at a recycling yard in TX. Vehicles that are heavier in the rear like a rear-engine VW, have a natural tendency towards oversteer. The ideal setup (for the track anyway) is a neutral or near neutral handling but because of various reasons, the auto manufacturer's prefer it if the car has a slight understeer because it's easier for a novice driver to regain control of the vehicle in an emergency situation. You can imagine that as the rear comes swinging around there may not be much you can do before you completely lose control (look up 1976 Porsche 911 Turbo crash statistics in your spare time for an example).
VW put a sway bar on the front to balance out the handling and presumably used a size that would add a little understeer for safety. If you stiffen the rear suspension with a sway bar, you increase the oversteer. Use a bigger bar up front, increase the understeer. Once you understand this, you can see why the advice against just upgrading the rear suspension can lead to handling problems. My goal was to obtain a balance for comfort and performance on all road surfaces rather than all out performance (in a bus, that statement might make you laugh like it makes me laugh).
All of these results are based on a KYB gas shock setup and the heavy duty sway bars. Stock means the standard size front only sway bar. Rear only, means no front bar at all, not even stock.
|Condition||Stock Parts||HD Rear only||HD Front only||HD Front and Rear|
|Wind buffeting||Plenty||Minimized||Better than Stock||Minimized|
|Fast U-turns||Wide||Tight||Front-end slides||Tight|
|Tight On-ramps||Slow down!||Better||Front-end slides||Best|
|Positive Road Camber||Neutral||Oversteer at limit||no change||no change|
|Lane Changes||Body Lean||Best||Better||Best|
|Sharp Turns||Body Lean||Oversteer||Slides||Light Rear-end|
|Steep Driveways||Normal||Heavy Jostling||Normal||Heavy Jostling|
First, as I said earlier, upgrade your shocks then consider whether or not you need sway bars. Adjustable bars are available to fine tune to perfection and I can see why you'd want them after trying all of these configurations because there doesn't seem to be a perfect combination using the parts I used: each set of improvements comes with trade-offs. If you only want to do the front or rear but not both, do the front because I think the potential for oversteer you get with only the rear could be dangerous in many circumstances and the jostling is annoying.
I bought these sway bars dirt cheap and was trying to minimize the costs but If I had to start over again I think I would try adjustable on the front and rear and take the time to dial them in. Let me know if you attempt this because I'd like to hear your feedback. If money was a factor I'd only go adjustable on the rear for my experimentation.
I can partially see why SAW discontinued their rear kit: price. If they had sold just the front bar for the lower price I bet it would still be available but the cost of both was simply too much to experiment with. Luckily the front bar is a universal design so it doesn't matter who vends it.
Upgrading the rear with a sway bar won't correct for slight amounts of sag. If it does it means you've over tightened the bushings at the wheel bearing end so back it off a little otherwise the rear will be too stiff.
The front sway bar counters the body roll on turns. I think this is what most people are looking to improve in the bus handling as the bus begins to track with the road instead of roll against the steering wheel.
The most interesting aspect about the handling when you upgrade both front and rear is that you can perform maneuvers at higher speeds but it's at the expense of traction. You soon discover that the 82 series tires (185R14C) and high center of gravity aren't up to the challenge of spirited driving: it's a bus after all not a sports car. If you drive like you did before installing the sway bars you will appreciate the improvement in handling but at some point 15" wheels and lower profile tires are required for further control with their trade-off in comfort.
As for wind buffeting, the rear sway bar has the biggest impact. Instead of being blown around on gusty days or passing vehicles the motion now consists of little pushes (the bus is still tall, heavy and narrow after all). I hardly notice this effect anymore while on trips. The front bar doesn't seem to combat the wind as much but it does help keep you from being blown into the other lane when a truck passes you.
The biggest negative that comes from installing the rear sway bar is that it locks up the suspension. If you rock the bus at the rear you can witness the effect. Because the IRS is a little less independent with the the sway bar installed, coming and going from driveway entrances tends to jostle the bus. If you do a lot of in-town driving then sway bars aren't for you. If you do a lot of mountain driving and enjoy the downhill curves the sway bars improve handling perhaps giving you more confidence as you drive.
I would like to start all over again with more of a tuning mindset now that I've driven buses with the factory shocks, KYBs with (and without) sway bars but I've save that for a future project. When I finally located some high end shocks for the bus and I removed the rear sway bar and this so far has been my favorite combination: oil filled shocks and a HD front sway bar provides best balance of handling and comfort.
Some 15" rims and lower profile tires with the appropriate spec tires while improving the handling would probably also require a softer shock. Balancing all of this requires a lot of trial and effort and money which is another reason KYBs sell so well: low cost to stiffen the suspension.
I don't know if these numbers stamped on the parts will be useful in future but I recorded them anyway for identification purposes. BugPack and Prothane are the same company BTW.
|Bugpack||Front bushing kit||6500-15|
|Prothane||Rear urethane bushings||62002|
|Prothane||Front urethane bushings||10043|
|Prothane||Rear bar end bushings||???|
06/13/03 - Created
07/13/03 - Corrected comment about ride height
04/12/04 - Added NAPA as a clamp source
10/06/04 - Mention of more brands of shocks and jostling effect
03/02/05 - Added Koni links
05/07/09 - Re-org: needed to be better organized because of its original length
09/06/11 - Fixed broken photos, added translate button, updated footer