Speedo Drive

Pinions   Worm Drive   Pinion Housing

Pinions:

28-tooth 11G3264 for 3-synch non-OD (with housing, also used on 4-synch non-OD):

16-tooth 17H8021 for 3-synch OD, note the scroll on the shaft:

26-tooth 22B654 for CB 4-synch non-OD, with scroll:

21-tooth 37H3463 for CB 4-synch OD and all V8s, it's said that repros don't have the original scroll: (Moss Europe)

20-tooth 37H8845 for RB OD:

Worm Drive: 9-start 1H3369 for 3-synch non-OD:

5-start 7H8294 for 3-synch OD (B&G incorrectly show a blue plastic item):spacer

10-start 22B468 for 4-synch non-OD, there is also a white plastic version 22B649:

8-start 22B3464 for CB 4-synch OD and all V8s:

9-start DAM686 for RB non-OD:

6-start 37H8844 for RB OD:

Pinion Housing

There are three types of housing - one for non-OD boxes both 3 and 4-synch as well as the auto (22H29), one for the D-type OD (17H8012) and another for the LH-type OD (37H1955). The non-OD type is completely different to the other two in that most examples seem to be plastic and include a flange with two screw-holes to attach to the gearbox. The OD types are similar in general appearance, the LH-type is held in the OD with a clamping fork (37H1957) that is secured with a single screw, but it isn't clear from parts lists how the D-type is held in, but may involve a pin (17H8034) and special screw (7H5894) with washer (17H5834).

22H29 uses a gasket 22H903 to the gearbox casing and seal 13H4024 for the pinion spindle. 17H8012 uses O-ring 7H8304 to the gearbox casing, a seal for the pinion spindle is not shown.

For the LH-type is a 'seal-oil' (35) 37H1956 for the pinion spindle and an O-ring (36) 37H3879 to seal the housing to the gearbox casing: (Leyland Parts Catalogue)

The spiral shown on the shaft of the pinion is a scroll-type seal which is designed to push oil that gets onto the shaft back into the gearbox, although only when the car is moving forwards of course. The cable inner is also spiral wound, although in that case the spiral is wound in the other direction which tends to tighten the construction of the inner while the car is moving forwards rather than expand it, which unfortunately tends to push any oil that does get into the cable, up the cable! After-market or currently available pinions may not have the spiral. But it begs the question as to why a spiral and a seal, surely if the seal id over the spiral part oil will leak past the seal? Maybe the spiral is to lubricate the housing the shaft runs in, and the seal only engages with the plain bit right at the end.

With Vee's replacement cable seemingly pumping oil into the speedo I decide to get both seals, replacing just the oil seal in-situ to begin if I can, removing the housing from the gearbox if not and replacing that O-ring as a matter of course (note that oil will almost certainly come out with the pinion housing removed). However Googling those numbers doesn't come up with any of the usual suspects, but browsing B&G comes up with NKC105A and NKC101A respectively, also available from others. But I want the cross-member clips and bulkhead grommet as well from having replaced the cable, and none of B&G, Moss, MGOC or Leacy have all five items! Rimmer's does though.

With the cable removed ... there doesn't seem to be a seal! Or if there is, it is pushed well down into the housing leaving more than enough space for a second seal:

It's a conventional lip seal which has to be drifted into the housing, so unless the OD rebuilder used something else which fell out when changing the cable, and I didn't find it, means they didn't fit one! Trying to press the new seal in wasn't working (some housings seem to have a tapered entry which would make starting the seal easier but this one doesn't), so with it wedged in at a bit of an angle I refitted the cable and started tightening the cable nut until the flange on the cable reached the seal and started pushing it in. Then removed the cable and worked round it tapping it into position bit by bit, before finally refitting the cable. As the nut starts bearing on the cable flange and that starts bearing on the seal the outer starts turning with the nut. There is what looks like a hex on the outer but none of my spanners fit it, so I have to grip that with Mole grips from below while using channel grips to turn the nut from above to finally tighten it.

So inner removed from the speedo end and cleaned yet again, replaced without fully fitting the speedo in the dash until I've done some miles to see if any more oil appears on the cable. If it does, and it starts working its way up the cable, I'll have to remove the housing and have another go, and since reinstalling it stuff I've read tends to indicate that the seal should be further in. The photo's not too clear but peering down it certainly didn't look like the end of a lip-type seal that I could see. But browsing other pictures of the pinion I find one that has a section of shaft at the lower end with flutes as well as the reduced diameter section, so the lip of the seal will have to be above the flutes to work. Meaning the one I've added won't do anything, and there probably is one already in there! Oh well, looks like I'll have to get the housing off, with some of the oil draining out to remove the shaft and drift the seal(s) out. In which case probably better to fit another new one.