Dormakaba THKIT Replacement Hold Open Assembly for Track Installations, for 8000,7400, and 7300

When a track-installed Dormakaba door closer stops holding open, the problem usually isn't the closure itself. It's the hold-open assembly inside the track mechanism. Replacing the full track arm costs more, takes longer, and often means redrilling the door face. The Dormakaba THKIT is the direct solution: a replacement hold-open assembly designed specifically for track installations on the 8000 Series, 7400 Series, and 7300 Series door closers. You replace only the worn component, restore hold-open function, and keep the existing closer and track hardware in place.

This is an OEM replacement part from Dormakaba, the original manufacturer of these closer series. If the closer body and track arm are in good condition and only the hold-open function has failed, the THKIT is the correct repair rather than a full track arm replacement. For the complete lineup of Dormakaba door closers and for all commercial door closers across every brand, browse our full catalog.

What Is a Track Installation and Why It Needs Its Own Hold-Open Assembly

A track installation (also called a slide track or parallel arm track installation) mounts a channel track on the door face. The closer arm slides along this track rather than connecting to a fixed point. This configuration allows the door to swing to wider opening angles than a standard regular arm or top jamb installation, often approaching 180 degrees, which is why it's specified on high-traffic corridors, hospital wings, and commercial spaces where full door clearance is operationally important.

The hold-open function in a track installation is built into the track assembly itself, not into the closer body. A friction mechanism or position-specific engagement within the track holds the door at the preset open angle. When that mechanism wears out from daily use, the door stops holding open and begins drifting closed, which defeats the purpose of the track configuration. The THKIT replaces only that internal hold-open mechanism, not the entire track.

Dormakaba THKIT Technical Specifications

Part number: THKIT. Function: Replacement hold-open assembly for track arm installations. Compatible closer series: Dormakaba 8000 Series, 7400 Series, 7300 Series. Installation type: Commercial. Manufacturer: Dormakaba (formerly Dorma). Warranty: 2-year limited. Sold as: Each.

Compatible Closer Series: What Each One Is

The 8000 Series is Dormakaba's heavy-duty surface-applied closer for high-traffic commercial and institutional applications, available with regular arm, parallel arm, top jamb, and track mounting configurations.

The 7400 Series is a compact surface-applied Grade 1 closer with adjustable spring sizes and backcheck for flexibility across a wide range of commercial applications. It uses a compact form factor that suits low-clearance header installations.

The 7300 Series is a compact surface-mounted Grade 1 closer with a fixed spring design and broad finish availability. It's specified on lighter-duty commercial applications where a smaller profile closer is preferred.

All three series support track installations when specified at time of order or when retrofitted with the appropriate track arm. The THKIT is the replacement hold-open assembly for all three. If you aren't certain which closer series is installed on your door, check the model number on the closer body itself, typically stamped or labeled on the cover or case.

When to Order the THKIT vs. a Full Track Arm Replacement

Order the THKIT when the track body and slide mechanism are intact and the hold-open function is the specific failure. The track arm slides, the door opens and closes normally, but the door won't stay in the open position. That's a hold-open assembly failure, not a track arm failure.