TYPE 2 Lowering Guide

Preface
The
following document has been produced to give relatively concise
information on lowering a type 2 VW. Safety precautions in the lifting
of vehicles or removal of components are not to be discussed, as it is
felt common sense prevails.

Introduction
The VW Type 2 suspension is torsional based,
torsion can be thought of as the angular stiffness of metal along its
axis. What this means is that suspension is derived from the 'springy'
properties of metal. The rear suspension comprises of two torsional
bars. The bar ends are machined with little 'v' grooves (splines) used for location and connectivity. The inner bar ends are locked in position and the outer ends attach to metal plates (spring-plates)
that connect the rear hub-carriers. This set-up allows the outer hub
assemblies radial movement to be controlled by the rotational twist of
the torsion bar.

The front suspension has two sets of torsion leaves.
The leaves comprise of a stack of long thin metal strips and are housed
inside each horizontal tube of the front beam. Which are locked into
place via a centralised internal block, which has internal machining to
match the exact cross-sectional area of the set of leaves. A grub-screw
and lock-nut locate the leaves into the central block and hold them
inplace. A trailing arm is attached to each end of the torsion leaves.
The arms have radial movement due to the torsional characteristics of
the leaves. Bolted in between the two trailing arms on each side of the
beam is a stub-axle this carries either the drum or disc, depending on
year of vehicle.

The rear of the vehicle is lowered without any
special equipment or modifications. It is a simple matter of removal
and reassembly. The principle of lowering the rear of the vehicle is to
change the spring-plate's angular relationship to the body's horizontal
line using the splines. The principle of lowering the front suspension
is to change the angular position of the torsion leaves. This is
accomplished by rotating the centralised internal block either by
fitting an adjuster or to cut'n'twist the beam tubes to allow
the re-positioning of the internal block. The latter method, is
undoubtedly the cheapest method, but does not allow for any adjustment.
So care must be taken to satisfactorily calculate the required drop
before any welding is carried out. The instructions presented here are
based on the cut'n'twist method. Fitting of adjusters should be carried
out with manufacturer instructions, but it is envisaged that if
adjusters are to be fitted. Then a pair should be fitted, one on each
beam to maintain torsional balance of the suspension.
Rear Lowering
The
rear suspension on the type 2 is relatively straight forward to modify
no special tools are required. Just what can be usually found in a
competent mechanics tool kit? The procedure is as follows :
1. Remove
rear wheels then remove the bolts holding the hub-carrier to the
spring-plate and then move the carrier out of the way being careful not
to damage the brake pipe in the procedure. The bolts holding the plate
to carrier will be very tight and will necessitate the use of an
appropriate length ‘breaker bar’. Also the lower nut and bolt has very
limited access and it is advisable to remove the handbrake cable to
allow sufficient access for the socket and extension bar.
2. Remove
the pressed metal cover from the front of the spring-plate and then the
outer rubber bush from the torsion bar housing.
3. Place two punch
marks at 12 o'clock orientation. One on the torsion bar end, the other
on the spring-plate. This gives a reference for adjustment and if
errors occur.
4. Carefully remove the spring-plate without
removing the torsion bar from its inner location. If this proves
difficult, wedge the rear of the spring-plate against the cast backing
of the bush housing. Then using a large drift, hammer the torsion bar
inwards to drive it into its inner location. Repeat this method slowly
drifting the spring-plate off the torsion bar.
5. Rotate the spring plate the appropriate number of torsion bar splines. Then reassemble in reverse order.
For
‘fine tuning’ the amount or rear drop a combination of inner and outer
splines can be used. This is discussed a little later in the document.
The amount of drop available at the rear is as follows:
Pre ‘72
Vans
manufactured before 1972 have 48 splines on the outer rear torsion bar.
This constitutes 7.50 of rotation per spline. The distance from the
centre of the torsion bar to the centre of the driveshaft is ####. This
is due to the trigonometric relationship given in (1) and illustrated
in figure 5.

Post ‘72
Vans
manufactured after ’72 have 52 splines on the outer rear torsion bar.
This gives approximately 6.90 of rotational movement of drop per spline
using the same relationship as given in (1).
Note
Vehicles
with ‘type 4’ engines fitted originally have longer spring-plates than
their 1600 counterparts, but maintain the same number of outer splines
(52). This effects the amount of drop per spline due to a longer radius.

Cont.....

Front Lowering

Step 1
Remove the front wheels and
brake mechanisms (hub, disc calliper etc). Remove the stub-axles, the
ball-joints securing the stub-axles to the trailing arms can be
difficult to separate. If a ball-joint splitter is not available, then
a large hammer may be necessary to free the tapered joints. With the
joint under compression slightly, a swift hard blow on the side of the
stub-axle, where the tapered joint is housed should free it. Great care
must be taken as not to damage the ball-joint rubber boot, once the
stub-axles are removed, remove all other apertures to allow complete
removal of the beam, i.e. handbrake cables, steering linkage and master
cylinder etc.

Step 2
With the beam removed you should have
something that resembles Figure 1, though the trailing-arms are shown
to be removed here, they can in fact be left attached to the beam. The
torsion leaves securing grub-screw can be identified on the beam tubes.
For ease of identification it is shown here at the front, but in fact
they are situated at the rear.
Fig.1
In
order to allow sufficient access to allow the necessary cutting of the
tubes and maintain original steering geometry the idler housing must be
removed. This is accomplished with the use of an angle grinder with a
cutting disc fitted. Carefully cut into the housing adjacent to the
original welds that secure it to the lower beam tube, paying attention
not to cut into the beam tube too severely. Also for all but the
mildest drops the bump-stop arms need to be cut off to allow sufficient
travel of the trailing arms. Once everything is removed complete access
is available and you should have something that resembles Figure 2.
Fig.2

Step 3
Highlighted
in Figure 2 are the necessary cuts that need to be made. These should
be about 75 millimetres apart centralised about the locking nut. This
distance is sufficient to allow the cuts to pass either side of the
centralised internal block, as illustrated in Figure 3. Mark the beam
ready for cutting appropriately, either with masking tape or two pairs
of jubilee clips that allow a greater accuracy of cutting.
Fig.3
Before
any cutting is carried out, it is brought to the reader's attention
that the torsion leaves are still housed within the beam. Obviously it
is catastrophic to cut through the torsion leaves and great care must
be taken as not too! The method for cutting the beam tube without
torsion leaf removal is to carefully with a good hacksaw blade cut into
the tube along the cut guides with a slight rotational movement.
Periodically checking until the tube walls have just been cut through.
Then move forward a little and repeat the process. The torsion leaves
are a good few millimetres below the inner surface of the beam tube. So
safely cutting the beam with the leaves still intact is easily
accomplished. This method is preferred rather than removing the leaves
altogether, as they can prove very difficult and frustrating to replace.
Now
with one tube marked up it is nearly ready for careful cutting, but not
quite yet. Before you cut the tube, you need to make some reference
marks. This reference allows the accurate length of twist to be
determined prior to welding. The best way to mark the beam is with two
good dot-punch marks either side of the cut. It is important to make
the marks significantly wide apart. This is so they are not obscured by
the cuts made, and more so when the edges of the cuts are bevelled to
allow for acceptable welding penetration.
With the entire marking
done make the appropriate cuts in one, and only one of the beam tubes.
Once the centre section has been freed, use the angle grinder to
carefully bevel the edges of the free section and the remaining side
tubes. This can be easily accomplished by lifting or lowering the free
section to allow access accordingly.

Step 4
Ok so far you got
one stripped beam, with the centre section tube cut through freeing the
centre torsion leave block. The dot punch marks are easily identifiable
allowing the reference of the original position. Now here comes the
maths to allow the accurate calculation of twist to give the desired
drop required. The maths behind the calculations is simple
trigonometry. Figure 5 illustrates the trigonometric characteristics
the characteristic relationship is given in Equation (2).

Equation
(2) needs to be manipulated and related to the beam and trailing arms.
The trailing arm length as illustrated in Figure 6 above represents the
radius R. The angle q is represented by the amount of twist in
millimetres. The amount of suspension drop is represented by r. Lengths
of R and r are relatively straight-forward to comprehend.
Representation of q by the length of twist can be a little confusing,
initially. This is explained as follows:

Consider
a circle (beam tube cross-section), as illustrated in figure 7. It has
360 degrees in its rotation and a complete perimeter given by pD. A
portion of the perimeter lP holds the relationship as given by Equation
(3).

Rearranging Equation (2) to give the required angle that results in lateral distance r Equation (4) is derived.

Now that the rotational angle is known, it can be related to amount of twist using Equation (3).

What
this all condenses to is, approximately 4mm of twist results in a one
inch drop and can be considered to be linearly proportional to that.

Using
the previously made dot-punch references this is easily determined.
With the correct twist distance implemented into the centre section, it
can now be tacked and then seam welded accordingly. Repeat the cutting,
marking, bevelling process for the other beam tube. Weld it accordingly
and reassemble everything in reverse order to dismantling.