The headlamp aim in 993s is set by rotating a pair of metal bevel gears which are mounted in the inner edge of each headlamp pod. The metal gears engage with a similar bevel gear made of plastic which has an M6 threaded stud moulded integrally with it. The reflector has two components which these studs run through. Moving the externally-accessible bevel gears turns the studs and moves the headlamp aim left/right or up/down, depending on which gear is being turned.
If your headlamp aim isn't readily adjustable it's a fair bet that one or more of these threaded rods has stripped, so that the reflector doesn't move when the gears are turned.
The plastic rod/gear assembly isn't available separately from the headlamp pods, which are about £600 new or £150 upwards for second-hand units - and the s/h unit may of course also have a stripped rod.
I had this problem and fixed it for a total outlay of less than £5 using an M3 x 0.6 bolt (35mm length), some M6 nylon stud, a 2.5mm drill bit and some plastic adhesive, although anything that will give a decent bond between steel and plastic should do the job.
Basically, a 2.5mm hole is drilled axially up the length of the gear, having first removed the old threaded portion. Cut the stud to the required length and drill a similar hole axially up the stud, to the depth needed for the bolt to snug up tight into it.
The holes are threaded to the correct size and the gear, bolt and stud are screwed together with the surfaces lightly coated in adhesive.
Seems to be as strong and maybe stronger than the original.
If your headlamp aim isn't readily adjustable it's a fair bet that one or more of these threaded rods has stripped, so that the reflector doesn't move when the gears are turned.
The plastic rod/gear assembly isn't available separately from the headlamp pods, which are about £600 new or £150 upwards for second-hand units - and the s/h unit may of course also have a stripped rod.
I had this problem and fixed it for a total outlay of less than £5 using an M3 x 0.6 bolt (35mm length), some M6 nylon stud, a 2.5mm drill bit and some plastic adhesive, although anything that will give a decent bond between steel and plastic should do the job.
Basically, a 2.5mm hole is drilled axially up the length of the gear, having first removed the old threaded portion. Cut the stud to the required length and drill a similar hole axially up the stud, to the depth needed for the bolt to snug up tight into it.
The holes are threaded to the correct size and the gear, bolt and stud are screwed together with the surfaces lightly coated in adhesive.
Seems to be as strong and maybe stronger than the original.
