MICROMATIC Rotac SB-18-1V User manual

RM - 26-10-77077Rev. D Page 1 of 9
OVERHAUL INSTRUCTIONS
RotacModel SB-18-1V
Bills of Material –26-10-7707 & 26-10-7712
Outline Drawings- 26-10-7707 & 26-10-7712 SHTS 1
Part lists- 26-10-7707 &26-10-7712 SHTS 2
For further information contact:
MICROMATIC, LLC
525 Berne St.
Berne, IN. 46711-1298
Ph 260 589 2136 Fax [phone]
www.rotachydroac.com

RM - 26-10-77077Rev. D Page 2 of 9
REVISION HISTORY
REV.
DATE
DESCRIPTION
BY
A
11DEC20
REVISED / ADDED INSTRUCTIONS REGARDING ECO 11815 & 11864; 1/2 - 13 TORQUE WAS 126 FT-
LBS, NOW 93 FT-LBS
STINSON
B
02SEP21
REVISED/ADDED NEW ASSEMBLY TOOL KIT REGARDING ECO 12151; TOOL KIT PART NUMBER IS
26-97-0348 AND 26-97-0349; TOOL NUMBER SK-4133 IS NOW REPLACED BY SK-5238-02
LUTHMAN
C
10SEP21
REVISED ASSEMBLY TOOL KIT BY ADDING TWO A010152 DOWEL PINS TO THE BOM
LUTHMAN
D
11FEB22
REMOVE SEALS A010263, A010264, AND 26-09-0714; THEY NEED REPLACED WITH 26-09-2813 SHAFT
SEAL AND 26-09-0539 O-RING REGARDING ECO 12368
LUTHMAN

RM - 26-10-77077Rev. D Page 3 of 9
ACTUATOR DISASSEMBLY, INSPECTION AND ASSEMBLY
INTRODUCTION
These instructions provide an overhaul procedure and parts lists for the SB-18-1V-DE-FLATS-FT and SB-18-1V-
DE-KEY-FT Rotac®Rotary Actuators.
Actuator overhaul should not be attempted without having a seal kit on hand. See table 4 for seal kit numbers. The
exploded & section views on pages 8 and 9, should be used for reference in following the overhaul instructions.
DISASSEMBLY
Read the special instructions below before proceeding. Reference exploded view drawings, on sheets 8 and 9, for
relative part location(s).
1. Clean exterior of unit as much as possible. This will help ensure that any material found in the unit is a
result of wear, system contamination or damage. A more accurate evaluation of the unit and operating
system will be obtained.
2. Remove all burrs from the shaft (4) around key-seats, end chamfers etc.
3. Before disassembly, the body (1) heads (2,3) and shaft (4) should be marked in order to return parts to
their relative positions during assembly.
4. After removing assembly screws from both heads (2,3), insert ½-13 screws in tapped holes provided.
Alternately tighten these screws to separate heads from body (1). Alternate: strike head of shaft with
plastic mallet or non-marring hammer and allow the shaft to push the end off. DO NOT PRY HEADS
OFF!!! Damage will occur to body or heads if you attempt to pry heads off.
5. Pull the shaft out, with a straight even pull, being careful that the shaft (4) does not fall and nick the body
(1).
IMPORTANT: DO NOT allow the shaft (4) to cock/tilt during removal as this may break the sharp edges on
the body, causing internal leakage during operation.
6. Remove all seals and inspect for cuts, nicks, or any other unusual conditions of the seal. (Compare to the
new seal kit).
INSPECTION/EVALUATION
1. Examine oil residue inside actuator. This may give a clue as to why any damage has occurred.
❖Contaminated oil will cause scoring of internal surfaces.
❖Varnish on internal parts can be a sign of hydraulic system running too hot.
❖Metallic particles may originate from valve spools, actuator internal parts and other metal
components in the system.
The appearance of any of the above will require flushing and cleaning of the hydraulic system.
2. Wash all parts thoroughly and examine for defects.

RM - 26-10-77077Rev. D Page 4 of 9
A. Shaft (Figure 1)
1. Examine the vane for cracks
on "A" diameter, keyways, and
any other areas where stress
may be applied.
a. Spot check by Magnaflux
can be used to check for
cracks.
Three different materials
are needed, and MUST be
applied in order:
SKC-S Cleaner
SKL-HF/SKL-S Penetrant
SKD-S Developer
FOLLOW DIRECTIONS
ON BACK OF THE CANS CAREFULLY
b. Key-seats that are widened will allow key
to move, damaging mating coupling and ultimately cause failure of the shaft and/or mating
part.
c. Scoring on "A" (major) diameter. See figure 1.
Any scratch .010 or more deep requires replacement of the part.
d. Scoring or galling on shaft journal. See figure 1.
This problem can be repaired with hard chrome; however, critical dimensions & finishes MUST
be held - this type of repair should be performed by actuator factory.
e. Scoring or galling on end of "A" (major) diameter. See figure 1.
This is another problem that can be repaired; however, it is recommended that this type repair
be performed by actuator factory.
B. Body
1. Any light scoring can be polished out with 400-grit emery cloth or equivalent. Scoring of .010 or more
deep indicates replacement of this part is necessary. When pressurized, the body will expand and
contract. For this reason, plating is not recommended by the factory for repair.
2. Cracks may be found across the dowel holes, screw holes or ports. This indicates replacement is
needed.
3. Dowel holes may be elongated or out of round. This indicates replacement is necessary.
C. Heads - See figure 2.
1. Scoring on face of head MUST be repaired. Possible causes are:
a. Dirty oil
b. Axial load on shaft.
2. Minor scoring can be polished out with emery cloth.
3. Cracks in head are usually around screw or dowel holes. Replacement of the part is necessary.
Figure 1 –Shaft Definitions

RM - 26-10-77077Rev. D Page 5 of 9
D. Seals - It is recommended that all seals be replaced.
1. Cutting or shaving of seals usually occurs during assembly.
This can occur in several different ways. Refer to assembly instructions for proper procedure.
SEAL REPLACEMENT AND ASSEMBLY
The assembly area should be clean to prevent contamination of parts assembly. A plastic or metal covered
workbench is the best. Parts should be re-cleaned if necessary. A small pliable brush should be used to clean
seal grooves, dowel holes, screw holes and other hard-to-get-at areas. Remove all burrs that may be on any
part. DO NOT break corners on shaft "A" diameter or heads of the body I.D. These sharp corners are important
to the operation and function of the actuator. They should be sharp but also burr free.
Tools
During the assembly of the unit, the seals need to be
protected. Assembly tools are required to install seal
kits. The tools are; a dummy head - to hold the shoe
seal during installation, a shoe seal protector, a vane
seal protector, and a shaft seal protector (reference fig
3 & table 3). Use a lubricant on all seals and internal
parts that is compatible with the driving fluid used. DS-
ES Lubriplate by Fiske Brothers is used at the factory.
Petroleum jelly is also compatible in most hydraulic
systems.
Assembly- reference Pages 8 & 9.
A. Place body (1) on a flat surface. Put two ¾” X 1”
long dowels into the body for the dummy head.
Attach the dummy head with two ½-13 X 1.50 long
SHCS so that it is properly seated. Turn the body
and dummy head over so that the dummy head is
on the flat surface.
B. Install the shoe seal cushion (6) and shoe seal cap
(5) into the body (1).
C. Lubricate the shoe seal cap (5) and the ID of the
body (1)
D. Insert the vane seal cushion (8) and "C" shaped
shaft vane seal cap (7) in the vane seal groove.
Lubricate to hold the seals in position. Lubricate
the "A" diameter of the shaft (see figure 1). Use
care to avoid nicking or cutting the vane seal. All
seal corners MUST remain sharp.
E. Place the vane seal protector on the body and
assure that it is properly seated. Place the shoe
seal protector over the shaft and place this
assembly into the dummy end. Rotate the shaft
approximately 90ofrom the shoe position. Slide the
shaft into the body until the vane is fully installed.
Remove the vane and shoe seal protectors.
F. Install spacer (23) inside groove and be sure it is
against the inside surface of the head, then install
O-ring (24) into same groove and shaft seal (22)
over the O-ring into that groove of head (3).
(Reference section views on pages 8 &9)
Smooth out ripples or wrinkles in the installed shaft
seal (22).
3
4
1
SK-5238-02

RM - 26-10-77077Rev. D Page 6 of 9
G. Place two wavy springs (20), hub seal ring (19), and hub seal (18) into the head (3). Ensure that hub seal (18) is
free to move axially. NOTE: Movement of this seal is essential to the proper performance of the actuator. Seal
should be a slip fit on the O.D. of the seal counterbore. Be sure top edge of counterbore is sharp- but burr free.
H. Place head seal (O-ring) (10) into the groove in the head (3).
I. Lubricate all seals and internal parts with grease, sufficient to maintain the seals in position when the head is
inverted and installed on the body (1)
J. (Unit 26-10-7707) Install the shaft seal protector onto the head of shaft (4). (See figure 3). Invert the head (3)
andcarefullyslideitdownovertheshaft. DO NOThammerontheheadorallowthehubsealtobecomedislodged
from its cavity as the head is mated to the body. Precisely align the dowel holes in head (3) and body (1). Install
two screws (15) 180° apart and tighten the screws to pull the head (3) onto the body (1).
(Unit 26-10-7712) Install the shaft seal protector into the bearing bore of head (3). (See figure 3). Install two
dummy keys in shaft (4) keyways. Invert the head (3) and carefully slide it down over the shaft. DO NOT
hammer on the head or allow the hub seal to become dislodged from its cavity, as the head is mated to the
body. Precisely align the dowel holes in head (3) and body (1). Install two screws (15) 180° apart and
tighten the screws to pull the head (3) onto the body (1).
K. Turn the assembly over and remove the dummy head, screws, and dowel pins.
L. Repeat steps F thru J for the second head.
M. Freeze four dowel pins (21) to -67°C and install through complete assembly.
N. Install remaining twenty-four screws (15) and torque all per table 1.
Factory built actuators are then tested for internal by-pass leakage and breakaway pressure. See chart in
table 2. Actuator should be cycled 10-20 times before beginning the tests.
TABLE 1 –TORQUE CHART
MODEL
SCREW SIZE
TORQUE
SB-18
½-13
93 Ft. Lbs/ 126 Nm –ungreased
*use Permalok # HM128 for all screws
TABLE 2 –BREAKAWAY & LEAKAGE CHART
MODEL
BREAKAWAY
PRESSURE
INTERNAL BY-PASS LEAKAGE–per minute
SB-18
100 PSI / 7 bar
10cu.in. @ 3000 PSI / 164cc @ 207 bar
INTERNAL BY-PASS LEAKAGE: Leakage checks to be made at pressure listed. The fluid is measured out the
exhaust port of the actuator. Pressure to be maintained listed for one (1) full minute before check is started. The
unit is tested in both directions.
BREAKAWAY PRESSURE: an operating pressure, as listed, MUST rotate actuator shaft through the full stroke.
The unit is tested in both directions.
EXTERNAL LEAKAGE: there should be no external leakage from the unit.
TABLE 3 –Assembly Tools TABLE 4 –Seal Kit
MODEL
SEAL KIT NUMBER
SB-18
26-90-7707
TOOL NUMBER
TOOL
SK-4312
DUMMY HEAD
SK-4318
VANE SEAL PROTECTOR
SK-5238-02
SHOE SEAL PROTECTOR
SK-4391
SHAFT SEAL PROTECTOR
SK-3229
SHAFT SEAL PROTECTOR
SK-4399
DUMMY KEY
26-97-0348 & 26-97-0349
ASSEMBLY TOOL KITS

RM - 26-10-77077Rev. D Page 7 of 9
TABLE 5
Trouble Shooting Guide
TROUBLE
PROBABLE CAUSE
REMEDY
External Leakage at Shaft
Defective shaft seal(s) (22) or cushions (O-
ring)(s) (24).
Replace defective parts.
Shaft (4) scored or worn. Bearing area in
head(s) (2 or 3) worn or scored.
Repair shaft or replace defective part.
External Leakage at Joint
Between Head (2,3) and
Body (1)
Defective O-rings (10), or damaged sealing
surface on head (2 or 3) or body (1). Improper
torque on the head screws(15).
Replace defective O-ring. Repair or
replace damaged parts.
Excessive Internal
Leakage
Defective shoe seal (5), shoe seal cushion (6)
vane seal cushion(8) and/or vane seal (7)
Replace defective parts.
Defective hub seal (18), hub seal ring (19), or
hub seal springs (20).
Replace defective parts.
Hub seal (18) stuck down
Remove burr (leave corner sharp!) at
top corner of seal cavity, polish seal for
slip fit to O.D.
Worn or scratched head faces on head (2 or 3)
or in body (1).
Repair or replace.
Worn or scratched ID of body (1).
Repair or replace.
Head screws (15) not tightened sufficiently.
Tighten to recommended torque.
"C" style vane seal (7) not seated properly
(applicable to units immediately after overhaul
only).
Operate through full cycles for a few
minutes to attempt to seat seals.

RM - 26-10-77077Rev. D Page 8 of 9
26-10-7707 EXPLODED VIEW

RM - 26-10-77077Rev. D Page 9 of 9
26-10-7712 EXPLODED VIEW