Trimmer Repair – Replacing the Upper Drive Shaft & Housing (Ryobi Part # 753-04344)

Hi, I’m Mark from
In this video, I’m going to show you how to replace the upper shaft on a Ryobi trimmer.
The upper shaft attaches to the engine on your Ryobi split shaft trimmer. The opposite
end attaches to the various accessories. The most common reason you need to replace the
upper shaft is wear to the coupling where the accessories attach. Replacing the upper
shaft is easy to do, and I’m going to show you how. Upper shaft assemblies, as well as many other
parts, can be found on our website. Let’s get started. I’ll begin by removing the
accessory from the motor shaft. The handle assembly is secured with five screws plus
one anti-rotation screw. I’ll split the two halves by removing those screws. Now remove
the trigger and the trigger spring. With the trigger removed, now I can go ahead and pull
the opposite half of the handle assembly away from the throttle cable. Now I’ll remove the anti-rotation screw
from the shaft, as well as loosen the clamp, then I can separate the shaft from the motor.
There are number of components on the old shaft that we’ll need to transfer to the
new one, so I’ll go ahead and remove those now. On the motor end, I have the spring, I’ll
pull that away. I’ll also slide the clamp off of the shaft, and then I need to remove
the handle. The handle has another anti-rotation screw on the bottom. I’ll go ahead and remove
that, and while we are at it, there’s another similar screw on this end of the shaft. Now I can loosen the screws that secure the
handle. And now I can just slide this assembly off of the shaft. Now the accessory clamp.
Again, there’s an anti-rotation screw. And the screw that tightens the clamp to
the shaft. Now I can install the upper shaft. You’ll notice that one end of the shaft
has a cast female end to receive the accessories, and that’s the end that the clamp goes on. The opposite end has a slit milled in it,
and that end will go into the engine. Now we’ll go ahead and install all the pieces
that we took off of the old shaft. I’ll start with the accessory clamp. I’ll slide
it onto the shaft until the holes for the anti-rotation screw line up, then I can replace
the anti-rotation screw and tighten the clamp screw. Now I’ll slide the handle back onto
the shaft. And again, I want to lineup the holes for the anti-rotation screws. I’ll use the hole that’s closest to the
clamp assembly, and I’ll tighten the screws and secure the handle. Then we’ll install
another anti-rotation screw. This one keeps the inner cable liner from rotating. Now I
can slide the clamp back over the shaft and replace the spring. Now install the shaft
back into the engine. The slot should go up toward the top of the engine. You want to
make sure that you align the spring with the clutch drum, and then insert the shaft until
the anti-rotation screw holes line up. Now I can reinstall the clamp. And again,
line up the anti-rotation screw holes, and install the anti-rotation screw. And now I’ll
secure the clamp. Now I’ll slide the throttle cable into the side of the trigger grip. And
I bring the cable in until it bottoms out on the shoulder
like that. Now install the throttle trigger. The alignment between the trigger and the
throttle cable is important. The end of the cable has a Z-shape to it. You need the fat
part of that Z (or the part that’s in line with the cable) to be on top of the trigger.
So align the trigger with the throttle cable and slide it through. And again, I just need
to make sure that this fat portion is on top of the trigger when it mounts into the handle. Now install the throttle trigger spring. It
wraps around the back of the throttle trigger, lines up with the hole on the trigger, and
then drops into the housing. As I slide the trigger and spring down into
the housing, I want to pull the spring back so it fits just in front of the plastic rib;
like that. Now I can install the other half of the throttle handle. I just want to make
that everything is aligned; the spring, the throttle trigger, and the throttle cable,
up against the shoulder; as I slide the two halves of the handle together. I’ll go ahead
and secure the handle with the five screws. Now I’ll install the anti-rotation screw
for the trigger handle assembly. There are two holes on the shaft that you can choose
from. You need to use the one that’s closest to the engine. You’ll know you’ve selected
the correct anti-rotation screw location, when the gap between the back of the handle
and the clamp on the shaft is about a quarter of an inch. So, I’ll line that up and install
the screw. And that’s all it takes to replace the upper
shaft assembly on a Ryobi trimmer. If you found this video helpful, be sure to give
us a thumbs-up, and leave a comment.

7 thoughts on “Trimmer Repair – Replacing the Upper Drive Shaft & Housing (Ryobi Part # 753-04344)

  1. Thank you for the helpfull tip , my question can that work as the same fir a craftsman 25 cc stright. Shaft mine boke at the clutch assm, do I have to buy the upper shaft or can I just buy the cable ? If u can let me know and pat number please and thank you ..

  2. Great video. If a parts supplier has a "how to" video it always influences my decision on where to buy my part.

  3. I like this video the shaft replacement assembly and the parts look exactly like the ryobi string trimmer I have I am going to install the part now.

  4. One of the best quality replacement videos I have seen. Even though I have a Troy Bilt 4stroke, I feel much more confident in changing out the upper shaft! Thank you.

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