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Suspension Question
shaihulud - December 21st, 2011 at 12:39 PM

I'm in the process of re-building a short wheel based buggy onto an 1958 pan.

It has a king pin front end and a swing axle rear end.

The brakes on the front will be converted to 4 stud discs. The rear is stock 4 stud drums.

It has a much reduced 1970 Beetle body so it will be heavier than a fibreglass bodied buggy and lighter than a Baja.

It has the original sway bar on the front. Because of mainly on road use I intend to keep that there.

I've removed the Z Bar or whatever it's called from the rear. It broke when I was removing it and I'm wondering if it's worth my while to fix and re-fit it.

This vehicle will be used mainly on road with only occasional fairly gentle off road use.

What does that rear Z bar do?

Why was it there?

Should I re-fit it?

Will it make much diference if I don't re-fit it?


68AutoBug - December 21st, 2011 at 02:28 PM

would love to see pics of the beetle buggy...

the z bar acted a bit like the front sway bar...

and stopped the rear axle from going positive camber like the early cars..

it must make a difference otherwise VW wouldn't have put it on.

the bump rubbers would be hard to find new these days as All beetles sold in North America from 1969 had IRS rear ends...
so only used on 1967-68 models...

LEE

I haven't had a front sway bar on My beetle so, I'm hoping it will make some kind of difference too...
when i get it on...
LEE


hulbyw - December 21st, 2011 at 05:20 PM

The Z bar does reduce wheel tuck under. Mine is shimmed so that it activates earlier. Makes a difference to the handling on a swing axle car. If you need new rubber bushes they are available as a kit from CIP1 in the USA or from Vintage Veedub in NSW. Also Wolfsburg Automotive have most of the bushes in Vic.
Lee, the front sway bar will make a good improvement.
Cheers......wayne


shaihulud - December 21st, 2011 at 11:35 PM

O.K. I'll re-fit the Z Bar.

Thanks for your info.


matberry - December 22nd, 2011 at 07:12 AM

Sorry to the above posters, but do your research or look under your car. The Z bar is purely an extra torsion bar or overload bar. As the vehicle rear suspension compresses, the Z bar starts to carry load and help support the load. It has nothing to do with wheel tuck and will only help reduce NEGATIVE camber as more load is carried. It was VW's way of trying to have a soft ride without compromising load carring ability.


AA003 - December 22nd, 2011 at 07:36 AM

Quote:
Originally posted by matberry
Sorry to the above posters, but do your research or look under your car. The Z bar is purely an extra torsion bar or overload bar. As the vehicle rear suspension compresses, the Z bar starts to carry load and help support the load. It has nothing to do with wheel tuck and will only help reduce NEGATIVE camber as more load is carried. It was VW's way of trying to have a soft ride without compromising load carring ability.


Yes it's just like a progressive spring. It probably would be usless on a lightweight buggy.


HappyDaze - December 22nd, 2011 at 08:08 AM

The 'Z bar', which has a similar effect to a 'compensating spring', will only work properly if it is connected to the axles via a rigid coupling. As Matt said, a stock VW 'Z bar' is really just a 'helper' spring. A 'Z bar [or comp. spring] does NOT work like a sway bar......in fact id does the OPPOSITE.

Racing 356 Porsches [swing-axle] mostly use very stiff comp. springs [or Z bars], with the torsion bars doing very little, other than holding the spring plates in place.


shaihulud - December 23rd, 2011 at 02:57 AM

Hmmmm!! That's very interesting. I wondered what it was for.

I seem to not need it on a lighter than stock vehicle.

Having raised the body by 2 inches on a lift kit, I'd have to modify it to be able to re-fit it, so I won't bother if I don't need it.

Thanks for your info.