New disks on HSZ50 not usable

I have added a couple of disks on an HSZ50 based array, TRU64 4.0d

The new disks are visible using scu:
scu> show edt

CAM Equipment Device Table (EDT) Information:

    Device: RZ28M      Bus: 0, Target: 0, Lun: 0, Type: Direct Access
    Device: RRD46      Bus: 0, Target: 4, Lun: 0, Type: Read-Only Direct 
Access
    Device: SDT-7000   Bus: 0, Target: 5, Lun: 0, Type: Sequential Access
    Device: HSZ50-AX   Bus: 1, Target: 0, Lun: 0, Type: Direct Access
    Device: HSZ50-AX   Bus: 1, Target: 1, Lun: 0, Type: Direct Access
    Device: HSZ50-AX   Bus: 1, Target: 1, Lun: 1, Type: Direct Access
    Device: HSZ50-AX   Bus: 1, Target: 1, Lun: 2, Type: Direct Access
    Device: HSZ50-AX   Bus: 1, Target: 1, Lun: 3, Type: Direct Access
    Device: DEC  P01  A12 Bus: 1, Target: 7, Lun: 7, Type: Processor

I used mknod to create the device special files:
mknod /dev/rzb10a b 8 17536
.....

and
mknod /dev/rrz10a c 8 17536

as well as ........ b 8 17600

This seemed to go OK too.

disklabel  seemed OK - 

 # disklabel -r /dev/rrzb10a
# /dev/rrzb10a:
type: SCSI
disk: HSZ50-AX
label:
flags:
bytes/sector: 512
sectors/track: 85
tracks/cylinder: 16
sectors/cylinder: 1360
cylinders: 3021
sectors/unit: 4109470
rpm: 3600
interleave: 1
trackskew: 7
cylinderskew: 26
headswitch: 0           # milliseconds
track-to-track seek: 0  # milliseconds
drivedata: 0

8 partitions:
#        size   offset    fstype   [fsize bsize   cpg]
  a:   131072        0    4.2BSD        0     0     0   # (Cyl.    0 - 
96*)
  b:   262144   131072    unused        0     0         # (Cyl.   96*- 
289*)
  c:  4109470        0    unused        0     0         # (Cyl.    0 - 
3021*)
  d:        0        0    unused        0     0         # (Cyl.    0 - -1)
  e:        0        0    unused        0     0         # (Cyl.    0 - -1)
  f:        0        0    unused        0     0         # (Cyl.    0 - -1)
  g:  1858127   393216    unused        0     0         # (Cyl.  289*- 
1655*)
  h:  1858127  2251343    unused        0     0         # (Cyl. 1655*- 
3021*)


All looks as it should (except partition a - should be unused)

Next create a file system:

# newfs /dev/rzb10c
Warning: /dev/rrzb10c is marked in use for 4.2BSD in the disklabel.
If you continue with the operation you can
possibly destroy existing data.
CONTINUE? [y/n] y
write error: 4109469
wtfs: No space left on device

I get this no space left message no matter what partition I use. I have 
run DILX on the two drives (read only) and no errors showed up so I'm 
guessing my rusty unix skills and aging memory are failing me.

Does anyone have any idea what step I'm missing? This server has been 
accessing other units on this HSZ50 for years....

TIA,

Ralf