How to Replace an SDS Chuck Mechanism

how to change sds chuck mechanism repair
In this Toolstop University guide we'll show you how to replace the SDS mechanism on your drill. There's a video walking you through the steps below, which you can watch on Toolstop TV or in our player.

There's some debate over what the SDS stands for, with some sources citing "Slotted Drive System" or "Special Direct System".

It's likely, though, that SDS as a term comes from the German phrase "Steck-Dreh-Sitz", which literally means Insert-Twist-Stay. And that's because the technology was originally developed by the German power tool giant Bosch back in the 70s.
repair sds chuck mechanism how to

The idea of SDS is that the drill bit slots and twists into the chuck, locking it in place. This is important for hammer drills, particularly when drilling or chiselling into masonry.

The bit is locked into the SDS chuck thanks to a ball bearing.

However, when this ball bearing becomes worn, or goes missing, the bit will no longer lock in place.

Tools You'll Need to Perform This Task

  • a tube of grease
  • a small screwdriver
  • circlip pliers

Step 1: Open Up the Chuck Mechanism

Make sure your drill has been disconnected from its power source. Then pull back on the chuck's sleeve, and using your small screwdriver, ease of the rubber cap.

Now the cap has been removed, the outer sleeve of the chuck will slide off.

Step 2: Remove the Circlip

how to repair broken sds chuck
Using the circlip pliers, squeeze the clip together then ease it up and off the chuck. This in turn allows you to remove the ball bearing retainer, the part of the chuck that grips the SDS bit.

Finally, in this step, remove the spring.

Step 3: Preparing the Chuck

You will be able to see the ball bearing contained in the slot of the chuck. This ball fits into the indentation on your SDS bit, locking it in place in the chuck.

Once your replacement SDS chuck has been unpacked, use your grease to lubricate the shank where the new ball bearing will sit.

Step 4: Fitting the New Ball Bearing

Now fit the new spring over the shank, followed by the curved, saucer-shaped washer. At this point, insert the new ball bearing into the slot. Once it place it'll hold the washer and spring in place.
how to fit new ball bearing to sds chuck

Fit the large washer on to the shank, followed by the retaining plastic washer. This washer has a groove and a raised edge. The raised edge goes down the shank first with the groove slotting over the ball bearing.

Fit the last washer then the front slide, which will all be held in place via the circlip.

Step 5: Re-fitting the Circlip

Using the circlip pliersintroduce the clip to the snout of the shank, easing it apart and down onto the ringed groove.

Use the small screwdriver if needed to ease it into place.

Now place the plastic cap down onto the circlip at the end of the shank.

The chuck has now been reassembled. Fit an SDS bit into the chuck and you'll find that it now locks safely into place.

Congratulations, you've repaired your SDS chuck! Safe drilling.

Watch it all in action on Toolstop TV.

If you've got any comments, questions, or suggestions for further Toolstop Unversity articles and videos, tell us below in the comments section.


Geert Welfing on Wed, 11 May 2016 15:23:45 +0100 (Likes: 0 / Dislikes: 0

Dear sir,
I know this article is more than 2 years old. I have an Bosch PBH 2500 RE which uses the SDS chuck kit as you use in the instruction video.
I have contacted many repair shops who all have repair kits but not this specific one. Can you tell me where you have bought this repair kit? Do you have an link?
Best Regards,

Martin McDermott on Mon, 30 Jun 2014 23:24:06 +0100 (Likes: 0 / Dislikes: 0

Are the circlips all the same size from drill to drill ? I have lost the circlip and don't know what sized circlip to buy.

Robert on Mon, 23 Jun 2014 19:43:10 +0100 (Likes: 3 / Dislikes: 0

I have sealey sds drill the drill bit keeps falling out where will I get a chuck from to repair it

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