Door Closer Maintenance, Repair and Adjustment

Hydraulic Door Closer Maintenance, Repair, and Adjustment info

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I created this page because I couldn't easily find information on repair of hydraulic door closers.

Disclaimer: This information may be inaccurate or dangerous, I am not responsible for your actions, use caution and common sense. I caution you to NOT disassemble the main cylinder, There's a strong high-tension spring inside that could seriously injure you if an end cap is removed.


I used standard household 3 in 1 oil to refill both door closers since the oil inside them and leaking from was lightweight oil. You might also try some hydraulic jack fluid - available at Wal-Mart's automotive section.

To refill the lost oil, I removed the various adjusting screws one at a time and added oil while the door closer was removed from the door frame. I cycled the door closer arm to work the air out of the system.

An 8 Fl. Oz bottle was ~$3.50 (Lowe's 2006). This bottle was more then enough.


These two closers, and all other closers I have come across have two common adjustment settings: Sweep and Latch. Norton (and others) also have a B.C. adjustment

SSwingRate adjustment for the long swing of the door - closing
LLatchRate adjustment for the short final swing of the door - latching
BCBack CatchBack-Catch adjustment to limit/slow the maximum swing of the door

I have adjustment info for two type styles of closers: Norton and Kawneer

Sweep is from full open to latch area, typically a little faster than the Latch speed.

Latch valve is to control the last few degrees of closing, speed is typically slower than Sweep to prevent the door from slamming into the Jamb.

For notes on adjustment, see below.

It is my opinion that the Sweep rate be moderate, and the Latch rate be slow. I like the door to close behind me and to latch slowly and quietly. However, if your latch bolt doesn't engage smoothly, you might require a rather quick Latch swing rate, to slam the door shut at the end of the swing. Also, you might want your Sweep rate to be slow if the people using your door walk slowly.


This Norton closer appears to be manufactured in the 1990s

Hinge side: note leaks.

Removal and inspection shows leak is from the top (and possibly bottom) arm seal(s) of the closer.

Repairing the arm seals is beyond the scope of my maintenance at the current time. The man-hours and labor cost required to disassemble, and then locate replacement seals would probably exceed the replacement cost for a new door closer.

This is the far side of the closer (away from hinges). It has the Back-Catch adjustment screw marked "B. C.".

I tried filling the housing with oil from the "B.C." hole, the results were no better than from the other two adjustment screw holes (following pic)

Here is a detail of the near side of the housing showing the Sweep and Latch adjustment screws.

This closer adjusts both closing rates independently. Screw in for slower, out for faster.


MOST door closers use two separate screws, the Kawneer shown below only uses one screw.

This Kawneer closer appears to be manufactured in 1966. It has two adjusting screws (needle valves), one on each side.The screw farthest from the hinges adjusts the Back-Catch: it limits/slows the swing before the door opens too far; e.g. so far that the door would hit a wall.

The screw nearest the door hinges has a bevel, this screw is used to adjust both the door short and long swing rates.

To adjust the door Sweep and Latch speed:
  • Set the Sweep rate first: Turn the beveled screw in and out to adjust the swing speed.
  • Once the Sweep swing speed is set, set the Latch speed: Turn the same bevelled screw 1/2 turn in or out from your Sweep speed setting. This will adjust your Latch speed, this is very sensitive!

Here is a picture of the bottom of the door closer, the two screws near the corners are used to secure the main casting to the mounting bracket. There are two more on the top.

Note the 'L' which is facing toward the floor. There is an 'R' on the opposite side of the housing. The housing is nearly symmetrical and can be used for a door which swing in either direction by flipping it and mounting the arm on the opposite side.

This is the mounting plate.

The screw farthest from the hinges adjusts the door stop: it stiffens the swing before the door opens too far; e.g. so far that the door would hit a wall. Screw this in to add resistance/adjust angle resistance begins.

Alternatively, you could adjust the arm length so that the reach is fully extended at a point just before your door opens too far. I didn't do this

I forsee two implications:
  • The door closer may not have been intended to extend this far. In this case, the door closer may sustain damage or higher amounts of stress.
  • The internal spring may fully compress/bind earlier in the door swing, taking (much) greater force to open the door or limiting Sweep travel. If you have high winds at this door, maybe that's good.
This is the leaking door-stop adjusting screw.
The damage is from me turning the screw in all the way, forcibly seating it, in an attempt to temporarily stop a leak.
The o-ring is visibly out-of-round, and is the source of the leak.
The Teflon tape was a failed attempt to stop the leak. The Teflon was disolved by the oil in a matter of minutes.

Here is a close-up of the damage done to the adjuster screw. Perhaps I shouldn't have screwed it in so tightly. Not that this damage greatly affects door-stopping performance.

Picture of the dental tool used to remove the old o-ring. Get at Wal-mart or hardware store.

Detail of the new o-ring seal, note the round profile, which sticks out from the side of the screw. This will make a better seal than the flattened old o-ring.

I replaced two o-rings, one on each adjuster screw. The cost was ~$.70 each (2006).

Note: As of May 29, 2007 (one year later); no leaks, hardware store O-ring works fine

Note: As of July 2008, (two years later); no leaks.

Harbor Freight Tools ( sells assortment sets of O-Rings online and in their stores - and at cheap prices!
To contact author: email
Thanks for the emails! They've been helpful for clearing up erroneous info and encouraging me to actually update this page.
Created: Feb 22, 2006
Last updated: Jun 30, 2008 - Re-formatted text, re-organized info, included updates from an old email about Norton closers from a helpful person cleared up S and L stand for Sweep and Latch, BC for Back Catch
Prev. updated: May 29, 2007 - I previously thought S and L on the closer adjustment screws was for "swing" and "latch". I now believe they stand for Short and Long throw door return speeds.
To Do: Add troubleshooting section (symptoms that point to low oil level, hard to open door because of BC out of adjustment). Add pictures of Norton closer from Vanessa. Rework HTML, use more tables, charts/illustrations. Further reorganize information so the reader can find the info they need QUICKLY.

©2006-2009 Christopher Parod