bagging a 412?
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73'vw412
- Posts: 42
- Joined: Thu Oct 06, 2005 8:10 pm
bagging a 412?
Has it been done? I want to lower my 412 with airbags, but before i get into this, has anyone else done it? how much modification will be required?
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tuna
- Posts: 2531
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Has it been done? Yeah:
http://www.oldbug.com/412.htm
As for the details of how to do it, I don't know. I suspect that the rear would be pretty easy, but the front struts would be a challenge. If you could get a bag-strut setup to work on the T4, you still have to deal with the ball joints, which we've discussed many times here.
Tuna
http://www.oldbug.com/412.htm
As for the details of how to do it, I don't know. I suspect that the rear would be pretty easy, but the front struts would be a challenge. If you could get a bag-strut setup to work on the T4, you still have to deal with the ball joints, which we've discussed many times here.
Tuna
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raygreenwood
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A handful of things. I am no expert on "bagging"....but a few problems in doing the 411/412 will exist. (1) There are permanent angle ranges in the suspension....namely the radius arms socket. Over-rotation will break it. This does not mean that ic cannot be fixed...just that it will take a nifty re-design of the bushings, the centering ring and the sockets themselves.
(2) The ball joints, though they are larger than most....are highly loaded. The internal springs are suspect. Putting air-bags on would take away a lot of the damping. That kills ball joints. (3) lowering heavily.....which is I assume...why you need bags in the first place.....radically changes the castor angle. Adjustments will be serious work. Without castor adjustment...you snap joints.
Am I suggesting that this should not be done? Not at all! Just that there is little room under the front end for bags without either serious fabbing or actually destrying something.
If someone makes an airbag that can fit inside of a strut coil...you have it made. Ray
(2) The ball joints, though they are larger than most....are highly loaded. The internal springs are suspect. Putting air-bags on would take away a lot of the damping. That kills ball joints. (3) lowering heavily.....which is I assume...why you need bags in the first place.....radically changes the castor angle. Adjustments will be serious work. Without castor adjustment...you snap joints.
Am I suggesting that this should not be done? Not at all! Just that there is little room under the front end for bags without either serious fabbing or actually destrying something.
If someone makes an airbag that can fit inside of a strut coil...you have it made. Ray
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67 newbie
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I have never seen a 412 front suspension, but a local fabicator here has done a few strut air bag setups. He removes the spring and cuts off the lower mount. Then drills a hole in both the top plate and bottom plate of the bag. Welds the lower part to the body of the strut then either welds the top plate to the shaft of the strut or bolts it to the top plate of the strut.
1st time I saw this done I was convinced the heat would cool the seals in the strut, but honestly it worked perfectly. He did not even have a leak. But he is an extremely good welder.
1st time I saw this done I was convinced the heat would cool the seals in the strut, but honestly it worked perfectly. He did not even have a leak. But he is an extremely good welder.
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tuna
- Posts: 2531
- Joined: Fri Apr 14, 2000 12:01 am
Air-bag struts are available for the popular cars, like Hondas, Toyotas, etc. Of course no one makes one specifically for the 411/412, but that doesn't mean someone couldn't adapt one to work. That isn't the issue: the issue is the rest of the suspension. Once we get those kinks worked out, then bagging shouldn't be a problem.
As for the rear, that should an easy remove the spring, replace with a conventional bag. You'd have to fabricate a shock mount of some sort, unless the air-bag manufacturers have come up with something to control the spring.
Tuna
As for the rear, that should an easy remove the spring, replace with a conventional bag. You'd have to fabricate a shock mount of some sort, unless the air-bag manufacturers have come up with something to control the spring.
Tuna
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raygreenwood
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That description sounds like the airbag on the front struts...is outboard of the strut shaft. If that is so.....meaning that the strut rod does not go THROUGH the center of the bag....then the operative question...is where are you going to put the bag? There is very little room under the front wings of the 411/412...for an outboard bag to be rotating left and right without striking something. Also....if the strut cartridge and rod are to remain.....the rod will rise upward without a clevis of some sort under the top plate. In less than 1" of travel...they will strike the hood.
The more logical place to put bags on the front of the 411/412...would be out toward the ends of the control arms..between the "T" subframe and the control arm....then remove the coil spring altogether...and as noted....produce a fat C clip or clevis to keep the top of the strut rod locked to the strut top plate as a unit.
The rear...yes is simple.....but do not under estimate the leverage produced by the long trailing wishbones. Ray
The more logical place to put bags on the front of the 411/412...would be out toward the ends of the control arms..between the "T" subframe and the control arm....then remove the coil spring altogether...and as noted....produce a fat C clip or clevis to keep the top of the strut rod locked to the strut top plate as a unit.
The rear...yes is simple.....but do not under estimate the leverage produced by the long trailing wishbones. Ray
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Guest
Re: bagging a 412?
For the fronts you'll want airstruts, either universal ones you weld in or adapt some in there from another car, see the 4wd disk thread in this forum for ideas. For the rear you can use universal bags made for a Ford truck or something that take the place of the shock on the 412. They're red and it's just a bladder, no plates or anything. All of this is pricey, plan on spending $1000-1500 DIY.73'vw412 wrote:Has it been done? I want to lower my 412 with airbags, but before i get into this, has anyone else done it? how much modification will be required?
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73'vw412
- Posts: 42
- Joined: Thu Oct 06, 2005 8:10 pm
Im going to be using slam specialties re6 bags up front and re7s on the rear. Im going to have my friend(who does bags a lot) do the front suspension. What he told me was that he was going to make a top a-arm and ditch the whole MacPherson strut setup. He went into a little more detail on this, but I got confused. 
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raygreenwood
- Posts: 11912
- Joined: Wed Jan 22, 2003 12:01 am
Wow!....what a waste! Are you sure you really want to screw up a nice vehicle that way just for lowering?
Thats what dumping the struts will do. The A-arms will work poorly...as you will have no axial support for those long A-arms down below. It will be rough and dangerous to drive. They will also never handle as well as the struts
Lowering is one thing. I appreciate where the sentiment comes from...though I personally think it is a total waste...to lower past the point of performance gains. To each his own. But......the body style, proportions and structure ....as well as weight distribution system of this vehicle were made for struts. A simple study of the vehicle with the suspension off...would reveal this to you.
Also...any welding of bracketry to the front end of this vehicle ....is incredibly dangerous. It is a crumple zone car. Do yo uknow exactly where the crumple zone engineered weak points are? After 28 years...still......neither do I and I have seen two of these vehicles collapse their front suspension while in motion....due to poor welding or mainetance in the front end area.
Not trying to be discouraging at all. Just a friendly warning. These cars....and their parts are far too rare to be casually cutting up. By that....I mean....study hard and long before you leap into non- reversible changes. You can do damage that you are notacapable of recovery from in the first five minutes of work on type 4's. Ray
Thats what dumping the struts will do. The A-arms will work poorly...as you will have no axial support for those long A-arms down below. It will be rough and dangerous to drive. They will also never handle as well as the struts
Lowering is one thing. I appreciate where the sentiment comes from...though I personally think it is a total waste...to lower past the point of performance gains. To each his own. But......the body style, proportions and structure ....as well as weight distribution system of this vehicle were made for struts. A simple study of the vehicle with the suspension off...would reveal this to you.
Also...any welding of bracketry to the front end of this vehicle ....is incredibly dangerous. It is a crumple zone car. Do yo uknow exactly where the crumple zone engineered weak points are? After 28 years...still......neither do I and I have seen two of these vehicles collapse their front suspension while in motion....due to poor welding or mainetance in the front end area.
Not trying to be discouraging at all. Just a friendly warning. These cars....and their parts are far too rare to be casually cutting up. By that....I mean....study hard and long before you leap into non- reversible changes. You can do damage that you are notacapable of recovery from in the first five minutes of work on type 4's. Ray
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raygreenwood
- Posts: 11912
- Joined: Wed Jan 22, 2003 12:01 am
I was hoping that I had not been too much of a hard ass in that post.... 
. Yes...the front ends are very peculiar. From what little I have seen...of air struts, they would bethe way to go. I would give the same warnings to anyone contemplating changing to a type 1 beam on the front end as well. For one...that unit would be incredibly heavy compared to the struts.
If there were tons of these cars around...and parts available...and front clips were available to re-work if you messed up...then it would just be down to your personnal safety issues.
That being said.....I starting thing about the configuration. If you were by chance going to use an upper A arm....it shoulld be bolted into the three bolt locations where the steering box and the idler arm bracket go. The configuration would have to have steel that went striaght down to clear the inner fender well...then back up on teh wheel side...with the A-arm...albeit a very skinny one.....on the wheel side. It would have to beamazingly short in order to end up centered above the ball joint. I'm talking like a 4" A-arm Then...for sure...you would have to build a side to side brace to put a steering box or rack on.
Lots of issues. In short...anything "could" work....as long as there is no welding to the unibody in that area. The suspension angles are lareday difficult. I think an air strut woudl be teh way to go. Ray
. Yes...the front ends are very peculiar. From what little I have seen...of air struts, they would bethe way to go. I would give the same warnings to anyone contemplating changing to a type 1 beam on the front end as well. For one...that unit would be incredibly heavy compared to the struts.If there were tons of these cars around...and parts available...and front clips were available to re-work if you messed up...then it would just be down to your personnal safety issues.
That being said.....I starting thing about the configuration. If you were by chance going to use an upper A arm....it shoulld be bolted into the three bolt locations where the steering box and the idler arm bracket go. The configuration would have to have steel that went striaght down to clear the inner fender well...then back up on teh wheel side...with the A-arm...albeit a very skinny one.....on the wheel side. It would have to beamazingly short in order to end up centered above the ball joint. I'm talking like a 4" A-arm Then...for sure...you would have to build a side to side brace to put a steering box or rack on.
Lots of issues. In short...anything "could" work....as long as there is no welding to the unibody in that area. The suspension angles are lareday difficult. I think an air strut woudl be teh way to go. Ray
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73'vw412
- Posts: 42
- Joined: Thu Oct 06, 2005 8:10 pm
Thanks again, Ray, as I havent put the car up on the rack yet, I dont know how the suspension is setup, and Ive been going off of the suspension on my 85' bmw 318i that has the same swingar-rear and strut-front suspension. I like the a-arm setup, but either way we go is going to take some long headscratching to get working right. What we were originally thinking of wouldve been an unequal length a-arm setup. Bolting an a-arm in would keep me from having to weld anything.