VW Heater Box Lever ModificationI bought two new
heater boxes to replace the ones on my '64 Bus (with '68 Beetle 1500
engine). The boxes on the Bus were the old style, 50 mm outlet ones and the
replacements were the new style, 60 mm outlet ones. I had to modify the
operating levers from the old boxes a little to get them to fit the new
boxes. This page describes the modification, with pictures.
Note that you can click on any picture to get a bigger
version. When you're done looking at the bigger version, use your browser's
"back" command to return here.
Here's the old heater box, as it came off the engine. No
extra charge for heater cable extension done by the previous
Here's the new heater box, as it was shipped to me. This
part is made by Dansk.
First, unhook the torsion spring from the operating
Next, remove the E-clip on the operating lever pivot. If
it's crusty, you might break it while removing it. No big deal - just get
another at the hardware store. I used a pair of needle-nose pliers to
remove it - sometimes it helps to use a small screwdriver and pry between
the clip and the pivot pin.
Now, remove the push clip on the flap arm pin. You can just
grab it with a pair of pliers and "walk" it off the pin. Note the marks on
the operating lever from the push clip...it is normal for the flap arm pin
to slide back and forth a bit in the slot as the linkage
Now you can remove the lever from the old heater box. Try
it on your new one - you may be lucky. I wasn't.
The problem was that the flap arm on the new box is wider
than the flap arm on the old box. For reference, the photos have a US
quarter, which is about 24 mm diameter.
I just bent the lever with my hands to make up the
Now the problem is that the slot in the end of the
operating lever won't fit over the flap arm pin anymore. I put the old
lever on the new box (flap closed) and pivoted the operating lever back and
forth, scraping the underside of the lever against the flap arm pin. Then I
held the flap arm all the way open and did it again. This will mark where
the new slot needs to go on the operating lever.
I drilled two holes, each a bit bigger than the flap arm
pin, in the operating lever to form a new slot. You might prefer to drill
one hole and lengthen the slot that is already in the lever. Yeah, I got
the slot a little off-center...
Put the operating lever on the new heater box and work it
through its complete range of motion. If it binds or hangs up, you need to
file the sides of the slot smooth, or lengthen the slot by filing or
drilling another hole.
Once the slot is taken care of, you can work on the
operating lever pivot pin. The old one had a groove in the end for the
E-clip, and the new one was missing the groove. I put the groove in with a
cut-off wheel in a Dremel tool, but you could also use a hacksaw. The
groove needs to be as wide as your E-clip is thick. The depth of the groove
depends on what size E-clip you have. If you're not sure, just duplicate
the groove on the old heater box as closely as you can. (Yes, the photo of
the old heater box pivot pin is horrible.)
When you're done with that, you can work on the torsion
spring. On my old heater box, the skin had a hole in it to anchor the
torsion spring. It was missing on the new one. I just used the old spring
to locate the hole on the new box and drilled a hole in the skin. Note that
there is a little flat place in the skin around the pivot pin - the hole
should go on this flat place.
Careful! Don't drill deep into the heater box, or you
might puncture the exhaust pipe inside! Just go through the sheet metal
skin of the box. If you want to make sure, put a little tape around the
drill bit about 1/8" (3 mm) from the point of the bit, and only drill until
the edge of the tape touches the metal.
Once the torsion spring hole is drilled, you can start
putting it back together. Put the torsion spring over the pivot pin, and
put the lever on the pin. Make sure the flap arm pin goes through the new
slot you made. Work the operating lever back and forth again a few times to
make sure it works smoothly. Put the E-clip on the end of the pivot
Put the push clip over the flap arm pin. Put one end of the
torsion spring in the hole you made and hook the other end over the
operatng lever. Lubricate the pivot points, and you're done!
Last updated Sun Dec 17 03:59:59 CST 2000