Looks like you can replace the "lower balljoint attachment" which contains the balljoint. From the looks of the new ball joint (on Rock Autos website) it looks like a simple nut and cotter pin assembly - which should be easy enough. Getting the lower balljoint attachment on and off is no big deal - just be sure to use locktight on the two bolts/nuts that hold it on and torque to spec. Directions from the service manual (if you'd like I can email the file to you with pictures, it's too large to send on this website):
26-22 FRONT SUSPENSION - FRONT SUSPENSION ARM SUB-ASSY LOWER NO.1
LH
Author: Date: 1798
2003 4RUNNER REPAIR MANUAL (RM1001U)
FRONT SUSPENSION ARM SUB-ASSY LOWER NO.1 LH
OVERHAUL
HINT:
COMPONENTS: See page 26-3
1. REMOVE FRONT DISC WHEEL
2. INSPECT FRONT SUSPENSION ARM SUB- ASSY
LOWER NO.1 LH
(a) Install the hub nuts to the disc.
(b) Using a dial indicator, check the lower ball joint for excessive
play when you push the hub nuts up and down with
a force of 294 N (30 kgf, 66 lbf).
Maximum: 0.5 mm (0.020 in.)
HINT:
If it is not within the specification, replace the lower arm.
3. SEPARATE FRONT SHOCK ABSORBER WITH COIL
SPRING
(a) Remove the bolt, nut and washer.
(b) Separate the front shock absorber with coil spring from
the suspension lower arm.
4. REMOVE FRONT SUSPENSION ARM SUB- ASSY
LOWER NO.1 LH
(a) Remove the 2 bolts, and separate the front lower ball joint
attachment LH from the front axle.
(b) Place matchmarks on the camber adjust cam No.2 and
toe adjust cam sub-assy.
(c) Remove the nut, camber adjust cam No.2, camber adjust
cam assy, bolt, toe adjust cam sub-assy, toe adjust plate
No.2 and front suspension arm sub-assy lower No.1 LH.
G20416
SST
G20164
G20412
SST
SST
G20164
G20413
SST
SST
FRONT SUSPENSION - FRONT SUSPENSION ARM SUB-ASSY LOWER NO.1
LH
26-23
Author: Date: 1799
2003 4RUNNER REPAIR MANUAL (RM1001U)
(d) Remove the cotter pin and the nut.
(e) Using SST, remove the front lower ball joint attachment
LH.
SST 09628-0001 1
5. REMOVE FRONT LOWER ARM BUSH NO.1 LH
(a) Using a hammer and a chisel, raise the flange of the bushing
diagonally as shown in the illustration.
(b) Using SST and a press, remove the lower arm bush No.1
LH.
SST 09632- 36010, 09950- 00020, 09950- 60010
(09951-00400)
6. REMOVE FRONT LOWER ARM BUSH NO.2 LH
(a) Using a hammer and a chisel, raise the flange of the bushing
diagonally as shown in the illustration.
(b) Using SST and a press, remove the lower arm bush No.2
LH.
SST 09632- 36010, 09950- 00020, 09950- 60010
(09951-00400)
G21680
G20166
SST
SST
Bush Positioning Protrusion
G20165
SST
Bush Positioning Protrusion
26-24 FRONT SUSPENSION - FRONT SUSPENSION ARM SUB-ASSY LOWER NO.1
LH
Author: Date: 1800
2003 4RUNNER REPAIR MANUAL (RM1001U)
7. INSPECT FRONT SUSPENSION ARM SUB- ASSY
LOWER NO.1 LH
(a) As shown in the illustration, flip the ball joint stud back and
forth 5 times, before installing the nut.
(b) Using a troque wrench, turn the nut continuously at a rate
of 2 - 4 seconds per 1 turn and take the torque reading
on the 5th turn.
Turning torque: 3.0 NVm (31 kgfVcm, 27 in.Vlbf) or less
(c) Check for any cracks and grease leaks on the ball joint
dust cover.
8. INSTALL FRONT LOWER ARM BUSH NO.2 LH
(a) Using SST and a press, install a new lower arm bush No.2
LH.
SST 09710- 26010 (09710- 05081), 09950- 60020
(09951-00890)
NOTICE:
Press the lower arm bush No.2 in the lower arm at the bush
positioning protrusions become perpendicular to the lower
arm as shown in the illustration.
9. INSTALL FRONT LOWER ARM BUSH NO.1 LH
(a) Using SST and a press, install a new lower arm bush No.1
LH.
SST 09223-00010, 09612-30012
NOTICE:
Press the lower arm bush No.1 in the lower arm at the bush
positioning protrusions become parallel with the lower
arm as shown in the illustration.
G20160
Matchmarks
G20159
C99159
G20160
FRONT SUSPENSION - FRONT SUSPENSION ARM SUB-ASSY LOWER NO.1
LH
26-25
Author: Date: 1801
2003 4RUNNER REPAIR MANUAL (RM1001U)
10. TEMPORARILY TIGHTEN FRONT SUSPENSION ARM
SUB-ASSY LOWER NO.1 LH
(a) Align the matchmarks on the camber adjust cam No.2 and
toe adjust cam sub-assy, temporarily tighten the bolt and
the nut.
(b) Install the front lower ball joint attachment LH, a new nut
and a new cotter pin.
Torque: 140 NVm (1430 kgfVcm, 103 ftVlbf)
(c) Install the front lower ball joint attachment LH with the 2
bolts.
Torque: 225 NVm (2,290 kgfVcm, 166 ftVlbf)
11. TEMPORARILY TIGHTEN FRONT SHOCK
ABSORBER WITH COIL SPRING
(a) Install the front shock absorber with coil spring, the bolt
and the washer, and temporarily tighten the nut.
12. INSTALL FRONT DISC WHEEL
Torque: 112 NVm (1,140 kgfVcm, 83 ftVlbf)
13. STABILIZE SUSPENSION (See page 26-12 )
14. FULLY TIGHTEN FRONT SUSPENSION ARM
SUB-ASSY LOWER NO.1 LH
(a) Fully tighten the bolt and the nut.
Torque: 135 NVm (1,380 kgfVcm, 100 ftVlbf)
C99159
26-26 FRONT SUSPENSION - FRONT SUSPENSION ARM SUB-ASSY LOWER NO.1
LH
Author: Date: 1802
2003 4RUNNER REPAIR MANUAL (RM1001U)
15. FULLY TIGHTEN FRONT SHOCK ABSORBER WITH
COIL SPRING
(a) Fully tighten the nut.
Torque: 135 NVm (1,380 kgfVcm, 100 ftVlbf)
16. INSPECT AND ADJUST FRONT WHEEL ALIGNMENT (See page 26-7 )