How to Identify the Right Char-Lynn Seal Kit for Your Hydraulic Motor
A leaking Char-Lynn motor almost always needs one thing: the correct seal kit. Get it wrong and you repeat the entire teardown. This guide shows you how to read the number stamped on your motor, decode what it actually means, and land on the right kit the first time.
The short version: the seal kit is determined by the product line and the design code, not by the displacement. Two motors of completely different sizes can take the same seal kit, and two motors that look identical can take different kits. Once you understand why, identification becomes mechanical.
Step 1: Read the full 10 digit part number
Char-Lynn and Eaton motors carry a 10 digit number stamped on the housing or on the data plate, in this form:
101 - 1001 - 009
product line | displacement and configuration | design code
- First three digits, the product line. This tells you the motor series. 101 is an H Series, 130 is an A Series, and so on. See the table below.
- Middle four digits, displacement and configuration. Shaft, ports, mounting, speed. This is what makes your motor physically different from the next one, but it has no bearing on which seal kit you need.
- Last three digits, the design code. Also called the engineering change code. This is the one most people ignore, and it is the one that decides your seal kit. Char-Lynn changed seal arrangements between designs, so a -005 and a -007 in the same product line can take different kits.
Write down all ten digits. If someone asks you for "the part number" and you give them 101-1001, they cannot help you.
Step 2: Look up your product line
The first three digits map to a series like this:
| Product line | Series | Notes |
| 101 | H Series | The classic general purpose geroler motor |
| 103 | S Series | Spool valve motors |
| 104, 105, 106 | 2000 Series | Higher displacement geroler |
| 109, 110, 111 | 4000 Series | Includes bearingless variants |
| 112, 113, 114 | 6000 Series | Heavy duty geroler |
| 119, 120, 121 | 10000 Series | Largest of the geroler range |
| 129 | J-2 Series | |
| 130 | A Series | |
| 146 | R Series | |
| 158 | T Series | Disc valve motors |
| 162 | W Series | Spool valve motors |
| 184 | Delta (DL) Series | |
| 2xx | Steering control units | 211 and 212 are Series 3, 213 and 214 are Series 6, 241 and 243 are Series 4, plus Series 5, 20, 25 and 40 |
Worth correcting a common mistake: 101, 103 and 104 are not all H Series. 101 is H, 103 is S, and 104 is 2000 Series. Plenty of parts lists get this wrong, and it is a fast route to ordering the wrong kit.
Step 3: The design code is what picks your kit
This is the part that saves you a second teardown. Within one product line, every motor sharing the same design code takes the same seal kit, regardless of displacement.
A worked example from the 6000 Series:
| Motor | Product line | Design code | Same kit? |
| 113-1070-006 | 113 | -006 | Yes, these two share a kit |
| 113-1148-006 | 113 | -006 | Yes, despite different displacement |
| 113-1082-005 | 113 | -005 | No, different design code, different kit |
So the two questions that matter are: what is my product line, and what is my design code. Displacement matters for buying a motor. It does not matter for buying a seal kit.
Step 4: Choose your seal material
Most Char-Lynn motors leave the factory with Buna-N (nitrile) seals. Buna-N handles standard petroleum based hydraulic oil at normal operating temperatures and is the right choice for the large majority of rebuilds.
Choose Viton (FKM) instead if your machine runs hot, or if the system uses phosphate ester, water glycol or another aggressive fluid. Fitting Buna-N where Viton was required is one of the most common causes of a repeat leak a few months after a rebuild.
Step 5: Decide which kit type you need
Not every job needs a full reseal. Depending on the motor, these are the options you will see:
- Complete seal kit. Every seal, O-ring and back-up ring needed for a full reseal. This is what most rebuilds call for.
- Shaft seal kit (front). For a motor leaking at the shaft only, with the rest of the unit dry and sound.
- Rear seal kit. For leaks at the end cap and valve housing.
- High pressure seal kit. For units running at the top of their pressure rating.
- Wheel motor seal guard kit. For wheel drive applications where the shaft seal needs extra protection from dirt and washdown.
If the motor has been apart for a while, or you are not sure what failed, fit the complete kit. The price difference is small next to the labour of doing the job twice.
What if the data plate is missing or unreadable?
It happens constantly on machines that have been pressure washed for twenty years. You can still get to the right kit by measuring:
- Shaft diameter, and whether it is straight keyed, splined or tapered
- Number of mounting bolts, 2 bolt or 4 bolt, and the bolt circle
- Port size and port configuration, side ported or end ported
- Overall length and the diameter of the geroler housing
Send those measurements with a few photos, including one straight down the shaft end and one of the ports, to info@restopower.com. We identify unmarked motors most days of the week and we will come back the same day.
Shop by series
Frequently Asked Questions
No. Within a product line, the seal kit is set by the design code, the last three digits. Two motors with very different displacements and the same product line and design code take the same kit.
Char-Lynn motor numbers are 10 digits in three groups. If you are reading 8, you are most likely missing the design code group at the end, or reading a casting number rather than the part number. Look again at the data plate, and check the housing near the ports.
A well made aftermarket kit is manufactured to meet or exceed the original Char-Lynn specification and uses the same seal materials. RestoPower supplies OEM or aftermarket equivalent kits with a 2-year warranty, and we source genuine new OEM when a job specifically calls for it.
Obsolete and hard to find is what we do. Send us the number even if Eaton has discontinued it. We carry or can source kits across the full Char-Lynn range including long superseded product lines.
Still not sure?
Send the full 10 digit number, or your measurements and photos if the plate is gone, to info@restopower.com or call (810) 882-1171. We will confirm the exact kit the same day. You can also use our quote request, or read the Char-Lynn and Eaton cross reference guide if your number has been superseded.