The procedure from the BBB, Modification Feb '68, for
Removal and installation of drive shaft for oil pump -- this is also refered to in this thread as the 'vertical drive'. it is the drive shaft for both the oil pump and the revolution counter ... tach. The 'horizontal drive' is referred to in the BBB as the idling gear shaft for injection pump--- refer to BBB Section 18-6/5 ==> Section 18-6, page 5, is:
There's also a section 18-6/3 which admonishes from using "bath nitrided" and non-bath nitrided shafts with one another rather than buying them in a set. There was a change sometime prior to Feb '68 which modified the two shafts to be bath nitride coated to improve the wear properties. The statement in the BBB is bolded and states
quote:
If only one of the previous pattern shafts [the pre-nitride coated ones] is replaced by a new one [a bath nitride coated one], the different wearing properties cause further damage after short mileage.
How do you tell the difference between the old (pre-nitride coated) and new (bath nitride coated) shafts? Easy... the bath nitrided shafts have a
turned slot 1 mm wideon them ... but where is this turned slot to be found?
On the Idling gear shaft (horizontal injection pump drive shaft) it's in the narrow section near large end of the shaft (I'll call the large end, the 'bottom' end), the narrowing of the shaft just below the gear and above the bottom bearing surface.
On the drive shaft for the oil pump, it's also found at the bottom end (literally) in the section just below a concave groove near the bottom of the shaft.
Since my BBB version in this section is a modification thru Feb '68, there's probably been an additional modification since then because the PN's listed for these shafts are the ones that somebody else has listed (later on this thread) as having been replaced by other PN's. However, if replacing only one (for example the oil pump shaft), be sure that the one you're replacing has the groove in it that identifies it as a bath nitrided one... since it's likely, perhaps, and therefore, that the horizontal shaft buried down below will therefore also likely be a bath nitided one.... and you won't be able to purchase a new non-bath nitrided one if the oil pump shaft doesn't have the 1 mm wide slot in it at the location described above.
[
my comments in brackets and italized]
Removal:1. Back off screw plug [
that's the 22mm screw on top] about 2 turns, unscrew hexagon screw with spigot [
that's the 10 mm screw on the side], and by inserting a screwdriver between the screw plug [22 mm plug] and the cover disk [
cover disk is first item directly beneith the screw plug], and push out the pressure piece upward. [
pressure piece is the the large cylinderically thick bronze/aluminum piece, referred to in previous posts on this thread as "bushing" ]
Note: [
note refers to an alternate method of extracting the pressure piece by using a special tool you fabricate by tapping and drilling another AM26 x 1.5 screw plug with an M8 thread.... ]
2. Extract helical gear/drive shaft from oil pump.
3. Completely unscrew the screw plug from the pressure piece and remove the cover disk and the rubber ring. [
no mention of a felt thingy, nor one shown in the cross section diagram]
Checking:4. Check the helical gear/drive shafter and bearing bushes [
top and bottom bearing surfaces on the "bushing" into which the helical gear/drive fits] for wear and replace if necessary. [
lotsa help that is ... define necessary].
Installation:5. Fit helical gear/drive shaft and pressure piece [
"bushing"] and tighten by means of hexagon screw with spigot [
the 10 mm screw]. Check end play (0.1 - 0.25 mm) [
0.004 - 0.010 inches] of helical gear.
Note: If end play is too small or excessive, remove pressure piece again. If end play is
too small, turn the
face of the bearing bushing by a suitable amount on a lathe [
good luck in your garage on this one... hence the suggested method by lapping on flat glass plate] and install pressure piece again. If play is
excessive, press the bearing bushing out of the pressure piece and correct end play of the helical gear by inserting the appropriate washers between the bearing bushing and pressure piece. Press bearing bushing with washer into the pressure piece and tighten he hexagon screw with spigot [
the 10 mm screw].
Check end play of helical gear again.
6. Place Rubber ring and cover disk in position and tighten screw plug.
[
That's all there is to it... makes it sound simple, huh?]
Longtooth
67 250SL US #113-043-10-002163
'02 SL500 Sport
