Char-Lynn Orbital Motor Rebuild Guide: Geroler Timing and Bolt Torque by Series

To rebuild a Char-Lynn (Eaton) orbital motor, you tear it down in order, inspect the shaft, Geroler and valving for scoring, fit every seal in the kit, then time the Geroler star to the drive (and on disc valve motors, to the valve plate and valve) before you torque the end cap or tie bolts to the figure Eaton prints for that series. Timing decides which way the shaft turns, and bolt torque runs from 14-15 Nm [120-130 lb-in] on a J Series to 130-150 Nm [95-110 lb-ft] on a 10,000 Series, so know your series before you pick up a wrench.

Every number on this page comes from Eaton's own Repair Information bulletins for each series, the October 2015 H Series parts and repair manual, and the 2007 Delta manual. Where the manual gives no number, we don't either. Keep the manual for your exact series and design code on the bench. This page shows you where the traps are and how the series differ.

Which Char-Lynn series do you have, and which manual covers it?

Char-Lynn motors come in three valve designs, and the rebuild splits along the same lines. Spool valve motors (J, H, S, R, T, W) time the star to the drive and output shaft. Disc valve motors (2000, 4000 Compact, Delta, 4000, 6000, 10,000) add a valve plate and rotating valve to the timing. VIS motors put the valve in the star itself.

Series	Product number starts	Valve type	Eaton repair manual we worked from
J	129-	Spool	7-144, designs 001 and 002
H	101-	Spool (gerotor, not Geroler)	7-117 (1999) and E-MOGG-RR003-E (2015), designs 007-009
S	103-	Spool	7-116, designs 008-010
R	146-	Spool	7-142, designs 001 and 002
T	158-	Spool	7-145, design 001
W	162-	Spool	7-157 (designs 002, 003); 07-01-158 (design 004 with parking brake)
2000	104-, 105-, 106-	Disc	7-124, design 006
4000 Compact	See tag	Disc	07-01-160, design 001
Delta	See tag	Disc	C-MOLO-TS003-E (2007)
4000	109-, 110-, 111-	Disc	7-118, designs 004 and 006
6000	112-, 113-, 114-	Disc	7-119, designs 005 and 006
10,000	119-, 120-, 121-	Disc	7-112, designs 002-004
VIS 30, VIS 45	See tag	Valve-in-star	7-150 and 7-153 (VIS 30); 7-151 and 07-154 (VIS 45)

Exploded views and the parts lists for each series are on the Char-Lynn parts catalog and service data hub. Two-speed 2000 and two-speed 10,000 motors have their own manuals (7-131 and 7-132) and are not covered here.

What tools do you need to rebuild a Char-Lynn motor?

• Torque wrench sized to the series. Eaton lists 17 Nm [150 lb-in] capacity for J, 34 Nm [300 lb-in] for H, S, R and T, 57 Nm [500 lb-in] for 2000 and 4000 Compact, 68 Nm [600 lb-in] for 4000 and W, 90 Nm [800 lb-in] for 6000, and 170 Nm [1500 lb-in] for 10,000.
• Sockets: a heavy duty 5/16 in. 12-point socket (Eaton no. 5422) for the end cap screws on H and S, or the 6-point E10 Torx socket (64489-000) on motors built with E10 screws. A 12-16 in. breaker bar.
• Shaft seal installation tool: 600470 for H -007 and S -008, 600523 for H -008/-009, S -009/-010, R and T, 600496 for the 2000 Series. The 4000 shaft face seal uses 600468 (-004) or 600421-2 (-006).
• Seal bullet or shaft sleeve: 600304 for 1 in. shafts and 600466 for 7/8 in. shafts on spool valve motors, 600465 for 1 in. 2000 Series shafts, 600463 for 1-1/4 in. 4000 shafts. No bullet? Tape the keyway and shaft end.
• Two alignment studs for disc valve motors, made from threaded steel rod per the manual.
• A small propane torch, an Arkansas stone, petroleum jelly, non-petroleum solvent and clean hydraulic oil.

Prep: wire brush the ports and joints, drain the motor, plug the ports, pull the key and stone the burrs off the keyway. Clamp across the mounting flange with soft jaws, never across the housing, which Eaton warns will distort. Scribe a line across all the sections. The J manual calls for it, and it costs nothing on the others.

What order do you take a Char-Lynn motor apart in?

Spool valve motors (H, S, R, T)

1. Shaft down in the vise, clamped across the flange edge.
2. End cap screws out (with their seal washers, on the smaller displacements that use them), then the end cap and its seal.
3. Lift off the Geroler (gerotor on H). Keep the rollers in the outer ring if they are loose.
4. Drive spacer (where fitted), drive, spacer plate and the housing seal.
5. Re-clamp across the ports. The four mounting flange screws are Loctited. Eaton puts break-loose torque at 34-45 Nm [300-400 lb-in] (35-45 Nm in the H manual) and running torque at about 11 Nm [100 lb-in]. Never use an impact gun on them. If they will not break, heat the housing where the screw enters with a small flame for 8-10 seconds while you pull on the wrench, and take the heat away the moment it lets go.
6. Twist the flange off; the shaft seals come with it. Pick them out with a bent, rounded screwdriver without scratching the seal bore.
7. Pull the shaft, needle thrust bearing and race.

Disc valve motors (2000, 4000, 6000, 10,000)

1. Shaft down, clamped across the mounting flange or retainer.
2. Tie bolts out. Lift the valve housing straight up. Done carefully, the balance ring, pins, springs and valve stay on the valve plate.
3. Balance ring with its inner and outer face seals, then the valve, the valve plate and the valve drive.
4. The Geroler (retain the rollers), the drive, then the wear plate and its shaft face seal.
5. Press the shaft and bearing out of the bearing housing (key off first), then work out the shaft seal, back-up washer and exclusion seal. On the 2000 Series the shaft and bearing assembly is sold only as a unit.

What does the wear tell you?

Eaton's instruction is short: check every mating surface and replace any part with scratches or burrs that could cause leakage. Clean metal parts in solvent and blow them dry. Don't wipe them with rags or paper towel, because lint ends up in the system. Stone off nicks; never file or grind motor parts. The manuals print no wear limits for the Geroler, so it is a visual call.

What you find	What it usually means	What to do
Scoring across the valve plate, valve or spacer plate faces	Dirt went through the motor	Replace the scored part and find the filtration problem, or the new parts go the same way
Scored or chipped star, ring or rollers	Contamination, or on an H Series gerotor, oil too thin for the load. Eaton calls for a minimum of 100 SUS on a gerotor, or the figure from 20 x psi / rpm, and 70 SUS on a Geroler	Replace the Geroler as an assembly. Eaton's parts lists carry it as one part number per displacement
Drive splines worn, twisted or stepped	Shock loads, hard reversals, or a stalled motor being driven	New drive, and look hard at the internal splines in the shaft and star
Groove in the shaft where the seal runs	Normal wear on a high-hour motor	New shaft. A new seal on a grooved shaft leaks from day one
Pitted thrust bearing or race	Contamination or heat	Replace. The race must spin freely once it is in place
Cracks near the flange seal seat	Overload or a bad hit	Replace the flange. The S and H manuals tell you to check this area every time
Shaft seal blown out	Case or return-line pressure above what the seal is built for	Fix the plumbing first. See Char-Lynn motor troubleshooting

How do you time a Char-Lynn motor?

Eaton's manuals say it plainly: timing determines the direction of rotation of the output shaft. On a spool valve motor you set the star to the drive and the shaft timing dot. On a disc valve motor you line up three things in order: the largest open pocket of the Geroler, the matching slot in the valve plate, and an opening in the valve. Swap a star point for a star valley and the motor runs backwards. Get it a tooth off any other way and, in our experience, it runs rough, weak or not at all.

Series	Timing reference	Standard rotation	Reverse rotation	Source
J	Corners of the spool drive end	Corners aligned with the star points	Corners aligned with the star valleys	7-144, p. 4
H	Mark one drive tooth and line it up with the timing dot on the shaft	Any star point on the marked tooth	Any star valley on the marked tooth	7-117, p. 7; E-MOGG-RR003-E, p. 12
S	Shaft timing dot lined up with any bolt hole; remember that hole	Any star point over that bolt hole	Any star valley over that bolt hole	7-116, p. 10
R and T	Shaft timing dot to any bolt hole; note the threaded hole in the housing	Any star point on the noted hole	Any star valley on the noted hole	7-142, p. 6; 7-145, p. 6
W (incl. parking brake)	Mark the drive using the mark on the shaft	Star point on the drive mark	Star valley on the drive mark	7-157, p. 7; 07-01-158, p. 10
Delta	Marked drive spline (lined up with the notch in the shaft)	Marked spline on a star tip (CCW with port A pressurized)	Marked spline on a star valley (CW with port A pressurized)	C-MOLO-TS003-E, pp. 8-9
2000 and 4000 Compact	Largest open pocket of the Geroler, marked on its edge	Valve plate slot in line with that pocket; valve side opening on that slot; turn the valve clockwise into the spline, 1/2 tooth max	Not described in the manual text	7-124, pp. 5-6; 07-01-160, p. 6
4000 and 6000	Largest open pocket, plus case drain and pressure relief holes in the Geroler lined up with the bearing housing	Same three steps, valve turned clockwise 1/2 spline tooth	Not described in the manual text	7-118, pp. 7-8; 7-119, p. 8
10,000	Largest open pocket; the valve has 8 ports	Same three steps, but the valve turns clockwise a full spline tooth	Not described in the manual text	7-112, pp. 8-9

Spool valve timing, step by step (S, R and T method)

1. Pour clean hydraulic oil into the output shaft cavity for start-up lubrication. Eaton says about 35 cc on H and S.
2. Turn the shaft so its timing dot lines up with one of the bolt holes. That hole is your reference.
3. Fit the drive. If its splined ends differ in length, the longer end goes into the shaft (on S -010, the wide end goes in on the 59 and 74 cc sizes).
4. Fit the spacer plate. On R and T, Eaton warns that the slots must pass oil as well as the screws; flip the plate and the motor will not run. On S, the chamfered side of the Geroler ring faces the spacer plate.
5. Set the Geroler on so a star point sits over the reference hole for standard rotation, or a star valley for reverse.
6. Rotate the ring to line up the bolt holes without pulling the star off the drive or rolling the seal out of its groove.

The H Series does the same job with a marked drive tooth instead of a bolt hole: mark one tooth, line it up with the shaft timing dot, then put a star point (standard) or star valley (reverse) on that tooth.

Disc valve timing, step by step (2000, 4000, 6000, 10,000)

1. Find the largest open pocket in the Geroler and mark it on the outside edge.
2. Fit the Geroler against the wear plate or bearing housing. On 4000, 6000 and 10,000, line up its case drain hole (and on 4000/6000 the pressure relief hole) with the matching hole in the bearing housing or wear plate. On the 2000, align the notch on the Geroler with the notch on the wear plate.
3. Fit the valve drive, then the valve plate. Find the valve plate slot that sits in line with the marked pocket.
4. Take any one of the valve's side openings and line it up with that slot. Turn the valve clockwise until the splines engage: 1/2 tooth maximum on 2000, 4000 Compact, 4000 and 6000, one full tooth on the 10,000.

How do you install the seals?

• Every seal in the kit goes in, lubricated with petroleum jelly. Don't stretch them into their grooves.
• Spool valve shaft seals: on S motors, break the sharp corner of the flange seal seat with 400 grit paper first. Load the back-up ring and pressure seal into the installation tool tube, lips up, and push the seal home by hand with a rotating action. Then look at it. If it is cut or cocked, replace it before you go further.
• 2015 update on the H Series: the October 2015 manual adds a medium pressure and a high pressure shaft seal that go in without the back-up ring. Fit what your kit contains and follow the 2015 manual on -009 motors.
• Disc valve shaft seals: on the 2000, the exclusion seal lip faces out, then the back-up washer, then the shaft seal pressed in on tool 600496. On the 4000, the metal side of the dust seal faces the flange and the flat side of the shaft seal faces the retainer.
• Getting the shaft through: bullet or tape over the shaft and keyway, grease between the dust seal and pressure seal, and twist the flange or retainer down slowly.
• Loctite on spool valve flange screws: wash the tapped holes with non-petroleum solvent, wire brush the screws, and throw out any with damaged threads or rounded heads. Three or four drops at the top of each hole (Eaton specifies Loctite 601 on S and Loctite 277 on R and T), screws in within 15 minutes, dry screws torqued straight away. New screws must be the correct length, 22 mm [.875 in.] under the head on H and S. A longer screw stops the flange sealing.
• J Series: the spool is match fit to the valve housing and is replaced only as a pair.

Char-Lynn cap screw and tie bolt torque by series

These are the end cap and tie bolt values from each manual, with the shaft-end fasteners below them. Torque in two stages where the manual says so, and always in the pattern given. Eaton notes on the 4000 and 6000 that pulling one bolt to full torque at a time can damage the bolt or the retainer.

Series (design)	Fasteners	Torque	Sequence	Source
J (001, 002)	5 cap screws	9-10 Nm [80-90 lb-in], then 14-15 Nm [120-130 lb-in]	Crisscross	7-144, p. 4
H (007-009)	End cap screws	Pretighten to 7.4 Nm [40 lb-in], then 27-28 Nm [235-250 lb-in]	Numbered pattern, Fig. 18	7-117, p. 8; E-MOGG-RR003-E, p. 12
S (008-010), 97 cc and smaller	End cap screws with seal washers	2-5 Nm [15-40 lb-in], then 23 Nm [200 lb-in]	Numbered pattern, Fig. 21	7-116, p. 11
S (008-010), 120 cc and larger	End cap screws, no seal washers	2-5 Nm [15-40 lb-in], then 34 Nm [300 lb-in]	Numbered pattern, Fig. 21	7-116, p. 11
R (001, 002) and T (001)	7 end cap screws	27-28 Nm [235-250 lb-in]	Crisscross	7-142, p. 6; 7-145, p. 6
W (002, 003)	7 end cap screws	28-34 Nm [250-300 lb-in], then 51-62 Nm [450-550 lb-in]	Crisscross	7-157, p. 7
W with parking brake (004)	7 cap screws, threads dipped in oil	34 Nm [300 lb-in], then 48.1-53.7 Nm [425-475 lb-in]	Crisscross	07-01-158, p. 12
2000 (006)	4 tie bolts	50 Nm [450 lb-in]	Alternately	7-124, p. 7
4000 Compact (001)	4 tie bolts	50 Nm [450 lb-in]	Alternately	07-01-160, p. 7
Delta	7 bolts, lubricated	56 Nm, plus or minus 5 [500 lb-in, plus or minus 50]	Crisscross	C-MOLO-TS003-E, p. 9
4000 (004, 006)	4 tie bolts (or studs and nuts on early models)	85 Nm [750 lb-in]	Numbered pattern, Fig. 23	7-118, p. 9
6000 (005, 006)	4 tie bolts (or studs and nuts on early models)	98 Nm [864 lb-in, 72 lb-ft]	Numbered pattern, Fig. 24	7-119, p. 9
10,000 (002-004)	4 tie bolts (or studs and nuts on early models)	130-150 Nm [95-110 lb-ft]	Numbered pattern, Fig. 22	7-112, p. 10
VIS 30 bearingless (002)	9 screws, lubricated	61-75 Nm [45-55 lb-ft], then 75-88 Nm [55-65 lb-ft]	Crisscross	7-150, p. 7
VIS 30 standard and wheel (002)	9 cap screws	102-115 Nm [75-85 lb-ft]	Crisscross, Fig. 8	7-153, p. 8
VIS 45 (003)	9 screws, lubricated	61-75 Nm [45-55 lb-ft], then 136-149 Nm [100-110 lb-ft]	Crisscross	7-151, p. 7; 07-154, p. 9

Shaft-end fasteners:

• H, S, R and T mounting flange screws: 28 Nm [250 lb-in], dry, Loctited, crisscross (7-116 p. 9, 7-117 p. 7, 7-142 and 7-145 p. 6).
• 4000 retainer, 8 screws, and 6000 retainer, 6 bolts: oil the threads, 6 Nm [50 lb-in] in sequence, then 34 Nm [300 lb-in] in sequence (7-118 p. 7, 7-119 p. 8).
• 10,000 retainer, 8 cap screws: oil the threads, 34 Nm [300 lb-in] in sequence. Bearing housing plug assemblies 100 Nm [900 lb-in] (7-112 p. 7).
• Case drain plugs: 6 Nm [50 lb-in] on the 2000 (7-124 p. 7), 17 Nm [150 lb-in] lubricated on the 4000 and 6000 (7-118 p. 9, 7-119 p. 9), 36 Nm [320 lb-in] on the 10,000 (7-112 p. 10).

How do you test a rebuilt Char-Lynn motor?

• Before it leaves the bench: on disc valve motors, check between the body sections for any seal that has squeezed out (the 4000, 6000 and 10,000 manuals call this out), and confirm the spring action on the valve housing.
• Let the Loctite cure. On H and S, Eaton allows 10-15 minutes with primer, 6 hours without, before the motor sees high torque reversals; other duty can run right away. The R and T manuals are stricter: the Loctite must cure completely before the motor goes into service, 6 hours, or 15 minutes with primer.
• Check rotation on low pressure before it goes back on the machine. A wrong-way motor is cheaper to fix on the bench.
• Speed sensor motors: turn the shaft until a target tooth sits centered in the sensor port, thread the sensor in by hand until it just touches, back it out a quarter turn plus whatever it takes to set the notches 90 degrees to the shaft, and lock the nut at 8.5-14 Nm [75-125 lb-in] on clean, dry threads.
• Run it in. Eaton's motor catalog recommends filling the motor with fluid before any load, then about an hour at 30% of rated pressure before full load.

Seal kit or full rebuild?

If the faces are clean, the Geroler is unmarked and the shaft has no seal groove, a seal kit and an afternoon will do it. Find the kit by series and design in our Char-Lynn motor seal kits, or read how to identify the right Char-Lynn seal kit first. In-stock parts ship within 24-72 hours and carry our 2-year warranty on in-stock parts.

If the Geroler, valve plate or shaft is scored, you are into parts, and on a small spool motor the parts can add up fast enough that a replacement makes more sense. That is a judgment call we are happy to make with you. Send it in and we do a free teardown evaluation and give you a firm itemized quote before any billable work. Repair work carries a 1-year warranty.

Frequently asked questions

Related reading

• Char-Lynn orbital motor troubleshooting
• How hydraulic motors work, and the main types
• Char-Lynn parts catalogs and service data, by series
• Char-Lynn part number decoder and seal kit finder
• Char-Lynn orbital motor cross reference
• Parker Torqmotor rebuild guide
• Char-Lynn orbital motors
• Hydraulic Motor Repair & Rebuild
• Hydraulic Pump Start-Up Procedure After a Rebuild or Replacement