Replacing a Broken Trimmer Rope
It never fails: Just as you are about to tackle some yard work on a Saturday morning, the pull cord on your Stihl trimmer breaks. Now you're stuck replacing a pull cord rope, adding another hour to your yard work and losing an hour of your day off. How are you supposed to relax on the weekend if you're constantly fixing your tools? It's my hope that these easy to follow instructions will get your Stihl trimmer up and running quickly, so you can get busy relaxing.
If you're working on a Stilh KM 56 RC trimmer, you're in luck because that is the machine I will be working on in this article.
One tool you will need, above all others, is a plug socket tool with a torx bit on the other end. This tool should have come with your Stilh KM 56 RC trimmer when you bought it. If you don't have one, buy one. It's worth its weight in gold. You will also need a new pull cord. I've listed links to both the torx bit and the pull cord below.
Tools You Need to Replace a Stihl Trimmer Pull Cord
Steps to Replace a Pull Cord on a Trimmer
Here is an outline of the steps you will need to follow in order to replace your pull cord. Pictures and more detailed steps can be found below.
- Remove the end cover.
- Remove the snap ring.
- Disassemble the unit into two pieces.
- Remove the coil from the shaft.
- Hold the spring in place after removing coil.
- Remove the broken piece of rope.
- Clean out debris on the cover.
- Measure out a new piece of rope.
- Thread the new rope into the coil assembly.
- Tie a small knot at the end of the rope and pull it into the coil pocket.
- Wind the pull cord rope around the coil.
- Reinstall the coil into the housing.
- Turn the coil two revolutions clockwise to add tension.
- Thread the rope through the hole in the end cover.
- Install the handle.
- Reinstall the end cover.
1. Remove the end cover. This will house the complete pull cord rope assembly.
2. Remove the snap ring that holds the pull cord rope assembly on the shaft.
3. Notice how the unit splits in two pieces. Also, notice how and where the spring is located.
4. Use a pair of needle-nose pliers to remove the coil unit from the shaft. Pull upwards to easily remove it from the shaft.
5. Once removed, hold the spring in place with your thumb to prevent it from falling out.
6. Remove the broken piece of rope from the coil unit.
7. Clean out debris on the cover.
8. Measure out a new piece of rope using the broken piece, adding a few inches in case of error. Melt the end with a lighter to make threading easier.
9. Thread the new piece of rope into the coil assembly.
10. Tie a small knot at the end of the rope and pull it into the coil pocket.
11. Wind the pull cord rope around the coil, using a piece of scotch tape to hold the rope in the groove.
12. Reinstall the coil into the housing, spinning it slowly until it drops into place. Do not force the coil, or you may damage the spring.
13. Turn the coil two revolutions counterclockwise to add tension to the return spring.
14. Hold the coil in place while you thread the rope through the hole in the end cover. Use a pair of needle-nose pliers.
15. Install the handle while holding onto the rope.
16. Reinstall the cover on the trimmer unit. You are finished!
Put Your Stihl Trimmer Back to Work
Now get to work and trim your heart out! If you have any questions about the installation, let me know by leaving a question or comment in the box below.
Questions & Answers
Question: How do I wind the bottom spring of my trimmer?
Answer: See Step 13 from my article. Turn the coil two revolutions counterclockwise to add tension to the return spring.
Question: My string got hot and melted after the second replacement. How long should the string be? Do you know if I should use the 3 or 4mm Stihl string? The 4mm string gets lodged under the housing for the recoil spring.
Answer: The string length should be about 2' 6''. I recommend using the 3mm string and do not overfill the spool.
Eddie Carrara (author) from New Hampshire on May 30, 2020:
I recommend you wrap it around the coil until it almost full and it can be installed easily. I don't know the actual length. I hope this helps.
Mike T on May 28, 2020:
Hi - my old rope is history and I do not know how long it was. Is there some way to tell how long a cord I need for my trimmer?
Eddie Carrara (author) from New Hampshire on May 04, 2020:
Did this help?
Jim Courtright on May 01, 2020:
I didn't know about the bottom coil spring,just the top one!!??
[email protected] on July 25, 2019:
When I removed the coil unit step 4 the bottom spring on the coil unit
sprung out and how do i rewind and replace it.
I see where one end of the spring goes in the coil unit but is the other
end left free until the coil unit is reinstalled???
Eddie Carrara (author) from New Hampshire on June 12, 2019:
Hi CJC-9 23,
The cord may have been too short and you jammed the mechanism. I recommend you remove the cover and inspect it.
CJG-9 23 on June 10, 2019:
I’ve replaced my pull cord and it worked for a while but this time I pulled it out and would not rewind ( stayed out), what did I do wrong?
Glen on March 28, 2019:
Excellent! Made it easy for me. Thank you.
Eddie Carrara (author) from New Hampshire on February 25, 2019:
You're welcome Ricky, thanks for the feedback, good too know :)
Ricky Gilbert on February 25, 2019:
This description was the most accurate and helpful of many I looked at on YouTube. THANK YOU!!
Eddie Carrara (author) from New Hampshire on June 11, 2018:
No, I don't know the size, but if you call a small engine repair shop I'm sure they'll have it in their books.
lee kulberda on June 09, 2018:
I've lost the bolts to the back cover on my KM 56 RC. Do you happen to know the sizes for them?
Eddie Carrara (author) from New Hampshire on April 30, 2018:
I'm so glad you found my my information useful, and I really appreciate you taking the time to write a comment, you made my day :)
Karen on April 28, 2018:
After hours of watching videos trying to fix my pull cord I found your video, its excellent good pictures and explanations so easy to follow for an old dear like me, thank you.
Eddie Carrara (author) from New Hampshire on February 06, 2018:
Thanks for the feedback Virgil :)
Virgil Smith on February 03, 2018:
Replaced rope on pole pruner. It has the exact same recoil mechanism. Had to use tweezers rather than needle nose. A very small needle nose would probably work. Have your wife thread the cord through the handle at the end. It's hard to keep the tension on the spring and thread the cord at the same time! Thanks, good pictures and explanation!
Eddie Carrara (author) from New Hampshire on October 31, 2017:
Not really, I just needed to fix my machine so I took pictures along the way and created a step by step tutorial :) Thanks for the feedback, I really appreciate it.
Kenneth C Agudo from Tiwi, Philippines on October 25, 2017:
Wow. Very clear and easy to follow. Surely, you are expert with this one. Thanks
Eddie Carrara (author) from New Hampshire on October 24, 2016:
I Agree 100% Jack, about the politicians lol.
Jack on October 23, 2016:
Very nice article! If only our politicians were this clear and efficient. Thanks for the help.....
Eddie Carrara (author) from New Hampshire on August 22, 2016:
We all lean by trial and error, I struggled with mine and then wrote the article and took pictures just to help others with the same issue. Your feed back is very important, so thanks for taking the time to comment :)
Scott on August 21, 2016:
Thanks eddiecarrara, very good article, I wish I would have read it first. Like Chris D and Rolf, my bottom spring popped off. I should have been more careful removing the spool. After rewinding and installing, the inner coil wasn't tight enough to engage in the inner recess where it needs to hook for recoil, so I probably need to buy a new rotor with rewind spring as described above. Thanks guys for the part number!
Rolf von Andrian on May 26, 2016:
I had the same trouble as ChrisD with the underside spring popped out. The trick is to put the spring back in to the casing the other way around as it is bend when is lays tensionless on the table. If you check the link above you can see how it should look like at then end.
Eddie Carrara (author) from New Hampshire on February 21, 2016:
Good info Chris, and thanks for taking the time to share it. It's people like you who keep this page going because there are so many problems you can run into when changing the pull cord, I only could share what I experienced when changing out my pull cord, I'm sure the info you shared will help many :)
Chris D on February 19, 2016:
Thanks very much Eddie. This is very useful information. I had the same problem as Tom N and LittleMCCBW where the underside spring popped out. The ring clip was missing on my unit (assume it broke off at some stage) so the rotor assembly flew out when I performed Step 1 above. The underside spring also had the strange set where two thirds of it wrapped 1 way, the other third wrapped the other way. It possibly develops this way when used since it doesn't start it's life out like this. When new it is wrapped tight up to the last 3 turns which then slowly angle in towards the center. But there seems to be no way that I could find to make it sit like this once it has been used. So if this bottom spring pops the best option is to buy a new module (it's called a "rope rotor with rewind spring" (Stihl Part Number: 4144-190-1111). I have a picture of the way the underside spring looks when it is new (no way to post this pic that I can see). I battled trying to reinstall the underside spring for a couple of hours so hopefully this addendum saves someone some time!
Eddie Carrara (author) from New Hampshire on July 04, 2015:
Sorry, not a clue, bring it to a hardware store and match it up, if it's missing, bring the part with you and find something that fits.
Jared on July 03, 2015:
Long story short, I have to replace the snap ring. Do you know what size it is?
Eddie Carrara (author) from New Hampshire on June 29, 2015:
Cool, thanks for the update Tom, I really appreciate it :)
Tom N on June 26, 2015:
Thanks. Turns out the lower spring took a strange set. Even the Stihl service tech couldn't get it back in. Got a new pulley for a few bucks, am now back in business.
Eddie Carrara (author) from New Hampshire on June 13, 2015:
Take a close look at pic #10 and #12, that should help, study the way the spring sit's in the holder and just repeat :) Let me know how you make out Tom, thanks.
Tom N on June 12, 2015:
Eddie, if you're still out there... fumbled the pulley and dropped it. Bottom spring fell out. The spring first wraps one way, then the other. Can't figure out how to wrap it back in. Can you help? Thanks
Eddie Carrara (author) from New Hampshire on June 04, 2014:
Thank you for the comment, it's very much appreciated. I do this kinda of stuff for people like you, someone who is just looking for answers to a problem they're having, so you are very welcome.
JonSEAZ on June 04, 2014:
I broke my pull cord (through, I think, not fully understanding how to use properly the Easy2 Start system) and located your instructions on the Internet at https://hubpages.com/hub/Stihl-KM-56-RC-Trimmer-Pu... Great photos and instructions. Simple, complete written instructions accompanied by clear photographs. Better than most factory manuals. Thanks a bunch. You are doing a great service here.
Eddie Carrara (author) from New Hampshire on May 23, 2014:
Hey Poop, just #2 Philip head screws
Poop on May 21, 2014:
What kind of screw on front plate?
Eddie Carrara (author) from New Hampshire on May 11, 2014:
Wind it on the spool until it's just under the top of the spool sides, I believe it's just about 2 feet of cord. Let me know if this helps, thanks.
MA on May 10, 2014:
Any ideas on he length of the cord? The whole thing broke on ours and we are trying to replace now, but need to know the length. Help!
Eddie Carrara (author) from New Hampshire on May 08, 2014:
I have never had that spring out before so I'm not sure of a trick to re-install it. Sorry I don't have an answer, but you must have to wind it tight enough to slip it into place?
LittleMCCBW on May 08, 2014:
Hi Eddie thank you for the instructions, unfortunately, I stupidly tried to do after reading only once. I had to leave to borrow a snap ring pliers and should have waited. I didn't tape rope into groove and when I went to turn counter clockwise to put tension on return spring, somehow the rope got tangled up and when I pulled the coil assembly out a second time to fix it, the smaller spring underneath that you don't show in your pictures just POPPED RIGHT OUT!! Scared me to death, but now I haven't been able to get the spring wound tight enough to put back together. My hands get sore and tired and start cramping up fast. That spring is a bear. Help, is there a trick I can use??
Eddie Carrara (author) from New Hampshire on January 11, 2014:
Hey Mr Crab, to add tension to the rope, check out step 12, 13, and 14. Let me know if this helps, thanks.
mr crab on January 10, 2014:
I have a stihl fs 56rc trimmer. I am installing a new pull rope and I can't get any tension on my spring to hold while I tie off the other end.
How do you put tension on this string while your pulling the rope forward? Am I missing something???
Eddie Carrara (author) from New Hampshire on August 22, 2013:
I haven't taken this apart in a while, but I'm pretty sure you're talking about step 13 in the pictures. Turn the coil counterclockwise two revolutions to add some tension to the return spring, but before you do this step, make sure you do step 12, spin the coil in the housing until it drops down into place. Let me know if this helps Tomcat, thanks.
Tomcat on August 22, 2013:
Hi Eddie, this is very helpful, but I need to rewind the underside coil that isn't shown in your pictures. Any advise would be helpful since I cannot find any tutorials or manuals online instructing how to do so.
Eddie Carrara (author) from New Hampshire on June 11, 2013:
This trimmer is pretty easy to disassemble, and the spring is pretty tame, not much recoil :) I appreciate the vote and the time you took to have a read :)
Eugene Brennan from Ireland on June 11, 2013:
If only they made all trimmers this way! I practically had to take my bargain basement trimmer apart to get at the pulley and cord!
Also when replacing the cord, there's no harm wearing safety glasses in case the spring jumps out.
Voted up, useful and interesting!