lowered beetle acceleration vibration

[nick68swingaxle]

I have a 68 swing axle beetle (i know this is only up to 67 but it's
The last year of the swing axle, it's lowered around 5 inches and it vibrates almost like a bucking on acceleration only it's seems to be better when it's cold and gets worse as it is driven. Just woundering if anyone has any ideas or have seen this. Thanks

[Potsie]

If it's lowered far enough that the axles are higher at the wheel than the transmission, then they won't get any gear oil. The gear oil may also be low, the symptoms of that tend to get worse when the car has been driving for awhile.

[nick68swingaxle]

Thanks for the advise I'm gonna check that level asap hope it comes around

[drscope]

I think your problem is the "lowered 5 inches".

Whats the history on this car? How long have you had it? Is this something that has recently developed? How long has it been running so low? Who lowered it - you or someone else? What is the rear toe settings? Are you running extended spring plates? have you checked the front transmission mount? Have you checked the rear transmission mounts? Does it do it worse on take off, or anytime you are trying to accelerate?
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Mother Nature is a Mean Evil Bitch!

[Al1968]

Hey nick68swingaxle I also have a 68 vw with a swing. Mines just inches off the ground and it's my daily driver. I know what you are talking about on what it's doing mine use to do that and I made some spring plate extenders to fix my toe and also found out that my front mount was in two pieces and the left rear was too. Now my car has a two inch tranny lift and no problems anymore. Is it doing it in all gears or just starting off from a stop I would check everything over to see if anything is loose.

[nick68swingaxle]

Thanks everyone I lowered it myself it does have exstended swing arms however I have not checked the mounts yet so I Will have to look at them of course it didn't do this before it was lowered, it only does it on light acceleration at lower rpm once u are going a constant speed it seems to be pretty good and like I mentioned it seems to get worse as u drive, when it's cold and 1st taken out it seems to not do it at all
Thanks again everyone

[nick68swingaxle]

Did u replace the mounts and put the plate exstenders in at the same time as the trans lift? Any idea what part fixed it or was it all done at the same time?

[drscope]

Whats your rear toe set at? Thats really important.

If your tranny mounts are good, your rear toe is close to being in spec, and it's doing this then I would suspect your fulcrum plates are protesting to being run out of their design range.

If thats the cause, then the best thing you could do is to raise it back up some. If you don't, the fulcrum plates will continue to wear and eventually one or more are going to either weld themselves to the axle spades or simply blow up and disintegrate. Either way they are currently depositing particles of very hard metal in your gear oil. That gear oil with those abrasive metal particles is what you are trying to lubricate and cool all the moving parts in your transmission with.
_________________
Mother Nature is a Mean Evil Bitch!

[nick68swingaxle]

^ thank you I believe my toe is good because I bought drop plates that are set up the be ok but I haven't been able to check it , I think I'm gonna try to raise it a couple splines, the mounts look to be ok and the trans is full.
Thanks for all the help

[drscope]

Oh man Oh Man! You can’t just bolt drop plates on and assume that the rear toe is good!

Because it’s a swing axle the rear toe will change as the wheel moves up and down. So you need to adjust the toe to the static ride height after you get finished setting that ride height.

It will NEVER be 100% correct simply because it’s a swing axle, but if you don’t check it and set it, it can be 100% incorrect!

With the car being lowered you already have massive amounts of steerage in each rear wheel simply because of the camber. Each wheel is leaning in and therefore trying to steer towards the center of the car. This causes a lot of tire scrub (along with MANY other problems) as each rear wheel fights to see which one is going to have the most grip.

Toe must be adjusted to try to compensate for the lean steer effect of the wheels. How much really depends on how low you go.

You went pretty far and I suspect a lot of your issues may be the fulcrum plates screaming for mercy! But you also need to address the physics of the issues going on between the pavement and the tread surface of the tires and which way it is trying to steer.
_________________
Mother Nature is a Mean Evil Bitch!