Here is a step-by-step procedure for having the driver’s seat belt recoil like in youth. In older cars dirt and simple use often causes the driver’s seat belt to become slow or unable to recoil fully.
I have just corrected the problem in my 5 doors 97 900SE and I would like to share my experience. Depending on the ability, for the average DIYSelfer it should take about 45 min or less to carry it out.
It requires a soft touch and a bit of patience. In different models or year the job may vary considerably. Please leave your feedback, comments and suggestions for further reference on the subject.
1-With a flat screwdriver open the upper section of the plastic trim that enclose the height adjustment knob. Start by prying it open at mid height on the door post near the rear door window ventilation opening were the lower trim goes under the upper one. Move carefully upwards, if too hard go under the four tabs at each corner with a thin screwdriver and lift them to disengage them. Leave the upper section and height adjustment knob cover dangling on the seatbelt.
2-Lift and remove the door ledge plastic trims (the one with Saab in big characters) both front and rear of the door pillar.
3-Pull both door’s gaskets in the section that hold the seat belt lower plastic cover to the door pillar.
4-Grabbing the seatbelt cover trim near the floor, pull out and disengage the two plastic pins that hold the bottom part. If too hard, bend the trim, locate the pin and help the pin out with a screwdriver.
5-Lift the cover trim, disengage the ventilation air duct and remove it.
6-Grab the seatbelt near the coil and pull it up and out a few times to get the feel of the current spring tension and recoil strength.
7-Clean the dust wool and dirt that has probably accumulated on the bottom and top guide in which the belt slide as well as in the drum where the belt is coiled.
8-Uncoil the entire belt and spray it with a good plastic trim product possibly containing Teflon. Avoid spraying the section that normally stays out side of the pillar. I find the silicon/Teflon unpleasant to the touch. As you spray, coil and un-coil the belt to lubricate it uniformly including the guides.
9-Depending on the condition of the recoil spring the cleaning and lubricating may already do the trick. Hold the top trim and slide cover in position and try the belt out. If the belt is still unable to recoil fully after letting it go then follow the next steps.
10-Remove the big bolt that hold the seat belt assembly to the chassis.
11-Gently disconnect the SRS belt tensioner wire connector. Remember that this is an integral part of the safety restrain system and should not be tampered with. It may have to save your life one day.
12-Hold the assembly in your hand and look closely at it to see how the different parts a located in respect to each other.
13-The assembly is mainly composed by four parts. The ratchet box (black box held together by plastic pins located on one side) the drum and frame, the SRS tensioner cylinder and frame (galvanized metal plate of different color next to the drum) and recoil spring box that is held together with the SRS frame to the drum frame by the two tork screws on the spring box (the only 2 screws visible at one end). The idea is to give the recoil spring a few extra turns to charge it up and increase the recoil strength. It should be done without taking apart the assembly by just removing the two screws ONLY and turning the box.
14-With one hand hold the assembly making sure that you keep a couple of finger on the black spring box. You should hold the whole thing so that when you remove the two screws the thing does not come apart. Bear in mind that inside the black box there is a charged coil spring that can’t wait to unwind itself and finally rest!!
15-Now comes the part that needs a bit of dexterity. Holding the assembly together (including the SRS cylinder and plate) remove the two small tork screws. While keeping the spring box against the SRS frame plate feel the now loose spring box, it wants to turn. While holding the parts together carefully turn the box in the opposite direction of where the spring wants to go. Try with 2 turns.
16-Put the screws back in and tighten them then re-install the assembly with the big bolt.
17-Try the belt recoil. If the situation is still not god enough repeat the above procedure. If after 4 or 5 spring turns the recoil is still not good than it’s likely that there is some other problem or excessive wear. Bear in mind that the belt should JUST recoil on itself, not shoot back. Check the other belts in the car for comparison.
18-Remove the big bolt, reconnect the SRS wire connector, put some tread locker on the big bolt and tighten it.
19-Reinstall the parts in reverse order starting with the bottom plastic cover. Make sure you connect the ventilation duck properly and locate the adjustment knob over the steel pin of the belt guide swivel. After boxing it up compare the parts fit with the opposite door pillar.
20-If the spring box uncoil itself in the charge-up process don’t despair. Take it out, look at the different parts to see where goes what and vice versa.
21-Holding in your hand the assembly, wind the whole belt on the drum (almost to the upper guide).
22-Put the spring box back on the assembly paying attention that the spring engages in the drum shaft connecting spline piece.
23-Un-coil the belt manually for a few turns Naturally the belt will try to lock up and stop paying out, be patient, gently pulling the belt out between look ups. You should now fill some pressure on the spring that wants to turn the box.
24-Give the box 5 turns as in step #15.
25-Put the screws back and secure the spring box.
26-Re-install the assembly and test it as previously indicated.
27-Repeat if further spring adjustment is needed.