Hey, I have lowered the front of the bug and now wanna lower the back to match front ride hight. Im running 14" / 15" stockers so how many mm low should i go? any pics and advice/info would be great. Please put up your pics for a bit of an idea for me aswell.
I have new rubber bushes to fit one day and chromed torsion bar brackets....
I don't know if I will lower My car though...
1500s had soft torsion bars....
many people say one large spline and two small splines?? or similar???
one large spline is too much by itself...
cheers
LEE
beetleboyjeff ·
I have done mine a number of times, and I am going to give Dylan a hand next weekend. I usually measure the distance from the end of the spring plate to the body as it sits now, then weigh the car down to where I want it (well, I have usually lifted mine, but same principle) and re-measure the distance. When I release the spring plates from the torsion bar housing and let it hang down, I measure the new distance to the body, then subtract (or add if lifting) the difference in the 2 measurements I did at the start.
I have found when taking the spring plates off the torsion bars, it is hard to tell which end of the torsion bar is comming out of the splines - the inner or the outer - so it is often hard to just move it one inner or one outer spline if you 'lose your place'. If you move the outside end one spline forward, and the inside end one spline back (there are a different number of splines on each end), you change the angle by 50' of a degree (from memory), so you can keep moving inside and outside until the measurment from the end of the spring plate to the body is what you had worked out. I do this to both sides, then look across under the car to see if both spring plates line up (are in wind) before I load any of them back into the torsion bar housing.
If anyone has other ideas or info, I am only too pleased to hear them.
bitemeoz ·
I just did mine and did 2 inners with 2.5inch dropped spindles at the front. looks the goods I reckon. when i did it i did what Jeff suggested and moved the splines and then basically just checked that both sides sat at the same angle before bolting all back up. Took me 2 hours and I am an IT guy not a mechanic so must be easy for anyone that knows anything about cars.
empi ·
Dont be a nancy and slamm the car!!
Aussie Dubbin ·
I find that getting them off is the most time comsuming part. Then set it to the height youthink will work and make sure the other side is the same.
I use a jack and chain to get the tension back into the arm without lifting the car. Also some threaded rod allows us to pull the plate back on over new rubbers. That way you get it all done up and then just loosen off one rod at a time and replace with original bolts. Yes it also work with car on. Just remove 5 or so of the guard securing bolts.
beetleboyjeff ·
Aussie Dubbin wrote:I use a jack and chain to get the tension back into the arm without lifting the car.
Also some threaded rod allows us to pull the plate back on over new rubbers. That way you get it all done up and then just loosen off one rod at a time and replace with original bolts.
I didn't know the jack and chain method when I had done them before, but I have read of it since, and had every intention of doing it that way. I wish I had known before though. :-)
I had not used threaded rod pull the plate back in, but I do use longer bolts - same thing I guess.
vwo60 ·
beetleboy jeff, that is the way i do it, that way you can get the ride height correct the first time, buy your self the correct tool to put the spring plate back onto the stop, it is a lot safer than the heath Robinson set ups that you see being used, http://www.pacificcustoms.com/AC000116.html
Be carefull about lowering the car to far as it will decrease the wheel travel and your car will be sitting on the bump stops, i found the best compromise for me is to run about 1 degree of negative camber, the car still rides well and there is enough wheel travel to absorb bumps in mid corner, tyre wear is still acceptable
Aussie Dubbin ·
If you have a spare $300 bucks put in bigger diamater torsion bars
beetleboyjeff ·
It is not my car - I am giving Dylan a hand.
I have done it about half a dozen times over the years.
Thanks for the link vwo60, that looks like a good bit of gear.
surfpig ·
a step by step guide of how i did it, how everyone does it 😉 (two splines)
One problem I can see is step 2 - Dylan has IRS on the back of his S bug, so it has the has the longer torsion bars with the short spring plates that have the extensions out over the end of the torsion bars - you can't see the end of the torsion bar to mark it like in the photo.
Otherwise, great photos - thanks.
Joel ·
I put a spline chart in the rear lowering how to thread.
I gotta laugh when people go to all the effort of the jack and chain method or that spring plate compressor tool.
THere is such an easy and cheap way around it, see the link.
DylanTheDubber ·
Thanks Joel,
Will be using your thread!
From Dylan
vwo60 ·
At work we have to carry out a hazard analisis on all jobs, if i applied it to angle iron method i would have serious issues with lifting the spring plate back onto the stop use the jack, it lifts the load off one of the stands and there is a possibility that the car could fall of the stands, the factory tool has no such issues as all the force is applied between two points on the car and has no issues with it slipping of and becoming a projectile, the factory tool is the simplest and safest method.
Joel ·
That's very impressive but most people working on their cars at home don't have to play by overly cautious OH&S rules that apply in work environments, just some common sense applied is all it takes.
By extending the spring plate length with the angle iron you're changing the amount of leverage needed to lift the spring plate up to such a small amount that at that length I can almost do it by hand but I have a rooted back and I'm just too lazy.
there is no way in hell you could lift the car when there is that much mechanical advantage on the spring plate, I could lift the whole back of the car with one hand if that was the case.
It may happen if you were doing to a floor pan only but all you would do is use a longer bit of angle iron.
vwo60 ·
Unfortunatly common sense is in short supply and those OH&s rules do protect people by catering to the lowest common denominator, DIY injuries are a largest contribuator to the inpatients at the local hospital. still concider the factory tool the safest
Joel ·
I hear what you're saying, and I have no doubt the factory tool is the safest just not everyone owns one.
matberry ·
The long lever doesn't change the lifting moment on the car. The load the torsion bar exerts to the chassis doesn't change, therefore the long lever method is only useable on lower ride heights where there is less bar preload to overcome to then slide the spring plate onto the stop. Stock or higher than stock and the car will get unstable on stands as said, so the factory jack method is for me too.
mickya ·
Not everyone can afford factory tools, however everyone has some angle laying around! I dont see using this method as unsafe, as long as the angle is of good length to not lift the car off of the stand. It certainly what ill be doing when i lower my car, and im a technician in the mines where safety is freakin crazy important dude
Joel ·
matberry wrote:The long lever doesn't change the lifting moment on the car. The load the torsion bar exerts to the chassis doesn't change, therefore the long lever method is only useable on lower ride heights where there is less bar preload to overcome to then slide the spring plate onto the stop. Stock or higher than stock and the car will get unstable on stands as said, so the factory jack method is for me too.
If you had a 2 spline lift I'd agree with you but mine at stock height with the angle iron at the length (about 500mm) requires very minimal effort to lift the spring plate up off the stop, most people could do it by hand.
There is definately no risk of lifting the car up.
Making the angle iron abit longer again would lessen the effort further.
vwo60 ·
You could make the angle 10 meters long, it will still the same force measured at the torsion bar to put the spring plate back on the stop, that does not change
Joel ·
Of coarse it doesn't change, that's not the point I'm trying to make.
What I'm talking about comes back to simple mathematics.
The further you come out from a pivot point the more mechanical advantage you get.
Like being on a see saw with the fat kid when you were a kid 😉
What is changing is how much force you need to apply to the angle iron to lift the spring plate up off the stop.
If you put a trolley jack directly under the spring plate then yes you will lift the car off the axle stands.
Extend the spring plate with the angle iron and move the jack further out this wont happen.
MISS VDUB ·
Haha factory tools the safest? Far from it. My VW's have a factory standard jack (widow maker), wouldn't use it if my life depended on it.
All options should be considered with doing any job, and other factors considered such as physical ability (eg: if you have a bad back, other methods and aids may need to be used to assist in completing the job)
Agree with Joel 100% on this one.
vwo60 ·
Joel, sorry to disagree with you but it requires the same force at the spring plate to lift it over the stop, the only thing that has changed is the force applied to the end of the angle , it will lift the car by the same amount to locate the spring plate back on the stop, the spring rate has not changed only the effort required, a repro factory tool costs about $30 US and has none of the issues of above as all the force is contained within the car, as for the old vw jack, if you follow VW's recommendations and use it on flat level solid ground with the car wheels chocked it will do the job every time, i just would not trust the jacking point
Joel ·
Alright I give up, this is just going round in circles, you use what works for you, I'll stick to whats worked for me.
And yes those jacks haven't earned a world wide recognized name widow makers for no reason.
I mean come on, metal on metal friction with a 1" round pipe to hold up half a tonne of car. 🙄
I chucked mine in the bin years ago, scissor jacks are much safer.
lauzboy ·
Sorry if this seems like thread hi-jacking...
Joel is correct. I'm a mechanical engineer and it's simple sum of forces and moments (torque).
The torque required to rotate the torsion bar to lift the spring plate over the stop is lets say 100Nm (just using nummbers here to illustrate...no idea if they're real!). You could achieve this by applying 100N (approx 10kgs) at 1m. Or alternatively 10N (1kg) at 10m. This is the sum of the moments about the torsion bar.
The sum of the vertical forces though is the weight of the car minus the applied vertical force. It's when this gets to 0 or negative do you start to get problems. So Joel is correct by applying a longer bar he can lift the spring plate with little force whilst having the car not lift. The other method of chaining the jack to the car essentially "grounds" the car to the jack. In this method the vertical force applied by the jack is more than the weight of the car.
vwo60 - your interpretation of forces and torque is slightly wrong. Yes the TORQUE of the torsion bar is the same, but the FORCE required to exert this torque varies with distance. The applied torque will not lift the car off its jack stands, only excessive vertical force.
vwo60 ·
As the spring rate has not changed it will take the same torque to twist the torsion bar to allow the spring plate back onto the lower stop, weather the angle iron bar is 10 meters long or 1 meter long, all that has changed is the force required at the end of the bar to generate the torque required, the longer the angle the easier it is, it will still try to lift the car of the stand exactly the same as if you applied the force directly to the end of the spring plate as the only thing that has changed is the lenght of the lever. if you check out the factory tool all the force is contained in the car with no chance of it slipping of the stands, this is similar to the chain and trolley jack method
lauzboy ·
you are 100% correct with everything you've said until...
vwo60 wrote:it will still try to lift the car of the stand exactly the same as the only thing that has changed is the lenght of the lever
Torque itself won't lift the car. Its the vertical force that lifts the car. This vertical force can be reduced by using a longer bar to produce the same amount of torque.
The reason why the factory tool works is that the force is being applied between the car and the spring plate. Using the jack method you are applying the force between the ground and car (spring plate). Its the point of application of the force which is key in this comparison
vwo60 ·
if i scrib a line on the torsion bar housing at the point were the vehicle begins to lift of the stand using only the spring plate and a trolley jack to lift it onto the stop then attach the angle bar and try to lift it onto the stop again it will still lift of the stand at the same scribed line.
bitemeoz ·
you guys are funny.
lauzboy ·
that means most likely your extension bar isnt long enough as the vertical force is still greater than the car's weight
baghall ·
Just saw this thread and not going to get into the debate over lifting cars or not. But looking at the springplate clamp reminds me of sringclamps for coil spring suspension. It looks like they would do the job as well and if you have them sitting in your workshop from working on other cars (as I do) maybe they would do the came job.
BTW when lifting the baja using a floor jack and chain didn''t seem all that safe due to the baja lifting approx 4-5 inches of the jack stand.
matberry ·
vwo60 wrote:if i scrib a line on the torsion bar housing at the point were the vehicle begins to lift of the stand using only the spring plate and a trolley jack to lift it onto the stop then attach the angle bar and try to lift it onto the stop again it will still lift of the stand at the same scribed line.
100% correct, it's the jack that sees less effort, the car will lift at the same torsional load.
lauzboy ·
Last post from me on this....
The physics involved is simple. With all due respect but there is some over complication and misunderstanding on terminology on this matter.
Torque in itself can't lift the car. Think about it like this... imagine that there is no spring plate at all and a pure torque is applied to the torsion bar. What happens? The "spring" will twist and twist and twist until either it shears or the splines strip. The car wont go anywhere at all. No lifting will occur.
Also think of just a coil spring being wound up between your hands. You let it go and what happens? It will probably try to spring against your hands (outwards) but it wont jump upwards or downwards.
Coming back to the spring plate and torsion bar. So using some MADE UP numbers to illustrate the point...
So lets say your car weighs 1000kgs (ie 10,000N) or 250kg per corner (2500N). Lets also say the torsion bar needs 1500Nm to be applied to get it over the stop and the spring plate is 0.5m long.
I need to apply 3000N to the end of the spring plate to raise the torsion bar onto its stop (ie 3000N x 0.5m = 1500Nm). But the 3000N applied to the spring plate is greater than the weight of the car on that corner (ie 3000 > 2500) therefore I raise the car up before I can fully apply the 1500Nm torque.
So I add an extension to my spring plate to make it say 2m long. Now I only need to apply 750N to the end of the lever (750N x 2m = 1500Nm). And the applied 750N is less than the weight of the car in that corner (2500N).
In other words by using the extension bar I:
a) achieve the required torque (1500Nm)
b) reduce the effort required to do so (3000N vs 750N)
This is all on the assumption that the car is well supported and that the car is essentially "ground". If this isn't the case then all bets are off and you've got a Darwin Award waiting to happen.
Agreed that the factory tool does the job well , but not everyone has one and a simple compromise can be made by using the extension bar method.
matberry ·
mmm, an engineer that's WRONG, never seen that before...
Maybe torque isn't the correct terminology for the load transferred to the chassis by the torsion bar, but it is a force that has a twisting moment at the spring plate that is transfered to the chassis.
I am still convinced (I've done probable 300+ springplate adjustments and done this exact experiment) that no matter the length of the lever, the car will lift off the jack stand at the same amount of springplate twist (060's scribed line). I'm not going to post on this anymore....... :/ unless I have to 🙂
And Ash, most of us do have a factory tool, it's a std VW jack with a small modification.
vwo60 ·
Thank godness for that, the spring plate does not know that it has a piece of angle bolted to it
AndrewB ·
matberry wrote:And Ash, most of us do have a factory tool, it's a std VW jack with a small modification.
So wheres the pics? make this thread useful again....
DylanTheDubber ·
I Have been caught up with stuff, but ill try get pics up soon.
From Dylan
volk hogan ·
bitch bitch whinge whinge
Snap Crackle Bang ·
Here is another way to think of it. It comes down to different centres of rotation.
To rotate the spring plate into position you need to apply enough torque to overcome the preload. The torque doing this is is lever length x force.
To lift the back of the car off the ground you need to apply enough torque to rotate it around the front axle line.
The torque trying to do this is (lever length + distance from front axle to rear torsion bar) x force.
If you add a metre or 2 to the lever you get a much greater increase in torque at the bar, with a small increase in torque trying to lift the car.
But after you increase the lever much more than this you will find that the torque about the torsion bar gets closer to the torque about the front axle. Consequently the lever method is not so good for high preload applications like off roaders.
Lauzboy's theory is correct, but Mat is right in practice.
Still I like the lever method because you can stand on a kitchen scale and lift the lever just enough to get the spring plate off the stop to measure the preload. Matching the preload on the other side is then easy.
I am also a Mechanical Engineer, please don't hold it against me!