Those who were at VSCC Prescott may have noticed my inability to get off the line for the afternoon runs.
The pinion had stripped it's teeth.
I started to take things apart as soon as possible, as you do.
The axle is a long nose 30/31 type that I'd bought from someone I know well. It was rebuilt but never I never inspected it or took it apart. I strongly believe the vendor never really inspected it either.
Due to a hub puller made of cheese full disassembly has to wait until one arrives, so I decided to remove the torque tube and look inside.
On removing the torque tube I saw this
No teeth - I expected this but I didn't know that the pinion ball race had been replaced by a roller, which in itself isn't a crime. What was wrong was that the roller race had self destructed.
I then took the torque tube apart and found that the pinion was in fact a later type with the 1 1/8 step, so the the bearing would be a lighter type roller, as described by Jack French in the standard texts. Not the ideal axle for a blown Ulster, so possibly waiting to break.
I then took a look inside the pinion housing and saw lots of rollers and could see where the outer race of the roller had walked forwards, let the rollers out and left witness marks on the edge of the crownwheel. My suspicion is that the roller outer race was missing the locating pin that is part of a D type axle. Naughty!
So then I went to the shed and looked for alternative axle parts.
Matched pairs are nice but I don't have a religious dedication to them, so looked for compatible parts. I found a good looking 5.25 set with a decent crownwheel but the pinion has one tooth with some bruising. Opinions on the usability of this would be welcomed, as would be the best approach to using a 1 1/8" stepped pinion in a long nose banjo and any alternative approaches.
When I get the full axle apart I'll check the diff for run out and the usual checks. The very expensive and critical AC bearings on the pinion feel good but will have a thorough inspection in due course.
Charles
The pinion had stripped it's teeth.
I started to take things apart as soon as possible, as you do.
The axle is a long nose 30/31 type that I'd bought from someone I know well. It was rebuilt but never I never inspected it or took it apart. I strongly believe the vendor never really inspected it either.
Due to a hub puller made of cheese full disassembly has to wait until one arrives, so I decided to remove the torque tube and look inside.
On removing the torque tube I saw this
No teeth - I expected this but I didn't know that the pinion ball race had been replaced by a roller, which in itself isn't a crime. What was wrong was that the roller race had self destructed.
I then took the torque tube apart and found that the pinion was in fact a later type with the 1 1/8 step, so the the bearing would be a lighter type roller, as described by Jack French in the standard texts. Not the ideal axle for a blown Ulster, so possibly waiting to break.
I then took a look inside the pinion housing and saw lots of rollers and could see where the outer race of the roller had walked forwards, let the rollers out and left witness marks on the edge of the crownwheel. My suspicion is that the roller outer race was missing the locating pin that is part of a D type axle. Naughty!
So then I went to the shed and looked for alternative axle parts.
Matched pairs are nice but I don't have a religious dedication to them, so looked for compatible parts. I found a good looking 5.25 set with a decent crownwheel but the pinion has one tooth with some bruising. Opinions on the usability of this would be welcomed, as would be the best approach to using a 1 1/8" stepped pinion in a long nose banjo and any alternative approaches.
When I get the full axle apart I'll check the diff for run out and the usual checks. The very expensive and critical AC bearings on the pinion feel good but will have a thorough inspection in due course.
Charles
