Saab 96 - Repairing a Door Lock


Early Saab cars have a propensity to break their locks.

Thankfully the main ignition switch seems more reliable, but both door and boot locks can give trouble.

This page looks at the components of the lock and suggest ways to get it working again.


Saab Door Handle and Lock Parts

       
The handle can be removed from the car by taking off the inner door panel and the various handles. The door cards can be fragile so care should be taken to avoid damage where the clips attach.
Handle Clamp Screw

Small Handle Screw Behind Door Panel
With the panel removed the exterior handle can be taken off by removing the small screw at the front end of the handle and the clamp screw in the end of the door.
   
With the handle on a clean bit of bench the lock barrel assembly can be removed by unscrewing the short screw in the end (circled).
removing the Lock Barrel
   
The outer chrome sleeve can just be pushed off the barrel by hand.

Removing outer Sleeve
   
To strip the lock down further the key is needed to release the holding pin.
The pin is spring loaded but can only be depressed with the key partly rotated.

It is necessary to wriggle the key to find the orientation where the pin can be pressed. Then a small screwdriver can be used to press the pin in far enough to slide the lock apart.

Using Key to Release Pin

Splitting lock
 
The same key rotation and holding pin is used to release the next lock sheath.
However be aware that this inner cover holds the small lock pin springs in place. Care should be take to avoid loosing/damaging the springs.

Slide the cover back a remove each spring carefully or hold a finger over all the springs as the inner cover is removed.

In this particular lock, one plunger and spring was missing so the picture here shows only 5 springs. A complete lock should have 6.

First plunger spring revealed

Lock with Plunger Springs Removed
 
Under the springs there should be two brass pins in each hole.

Ideally you would keep the pins in a set order so that you can put them back in the same place, but they can be sticky and difficult to remove from years of grease and grime.

Image showing some of the brass pins visible.
 
If the pins get mixed up it should be possible to work out their position against the key profile.

The lock works by creating a level split line between the brass pins to allow the barrel to turn.

Each pin has a spring, upper plunger and lower plunger part. The lower plunger part has a pointed end which is orientated to work against the key.

All the springs are the same.

The total height of a pair of plungers should be the same throughout the lock, so a short lower plunger would need a longer upper plunger.

Click to Enlarge View
To work out their correct positions the key profile can be observed to identify the 6 working points as labeled above.
On this key there were 4 different height peaks.
Peaks 1, 2 and 5 were the same height and so these would align with similar plunger parts. Actually plunger set 5 was missing in this lock so is not shown but it would be assembled with similar parts to sets 1 and 2.

Peak 4 was the lowest peak so it had the longest lower plunger and consequently the shortest upper plunger.
Peak 3 was a bit higher than peak 4.
Peak 6 was highest of all and had the shortest lower plunger.
 
If any parts of a pin are missing or if a spring is lost or damaged then the complete set of parts from that pin of the lock can be removed. This makes the lock less secure but this is perhaps better than a lock which doesn't work at all.
It is worth cleaning the parts and lightly oiling them on re-assembly.
 
Many Saab locks fail because of wear in the actual barrel. This is very difficult to replace and requires a pin to be drilled from the back of the lock (arrowed).

However just turning the key without any pins in the barrel can sometimes show worn or burred parts that are catching. These can be carefully filed away. Adding some oil to get the parts sliding can help too.

Back of Lock Barrel
   
To re-assemble the lock the pairs of pin plungers need to be dropped into the correct holes.

To test the lock, each set of pins can be pushed down with a small screwdriver. Then inserting the key should lift all pins up the correct amount so that the barrel can turn.

Reassembling the lock
 
Before adding the inner sleeve and springs to the lock it is worth nothing how the barrel rotation is transfered to the output of the lock.

The barrel is offset from the lock centreline so an Oldham coupling is used to transfer the motion. This has a sliding plate which needs to be orientated correctly to engage with the barrel slot and the output plate.

Lock Output Parts
 
The most difficult part of the re-assembly is fitting the inner sleeve.
The sleeve must be pushed into place with each spring being added in sequence.
At the correct time the locking pin must also be inserted with its spring.
Finally the Oldham coupling has to engage as the sleeve is pushed home.

Partway through Replacing the Inner Sleeve of the lock.
 
The lock body and outer sleeve can be replaced by reversing the disassembly steps.
Replacing Outer Sleeve

Lock Barrel Complete Assembly
     
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