Velomobile maintenance
Worked on the velomobile for most of today. I really needed to replace the six ball joints that control the angle of the front wheels.
They were almost 20 years old and were pretty rusted as they were made of non-stainless steel.
One of them had actually rusted so bad at one point that it would not turn anymore. This alerted me to the fact I really needed to replace them.
I had had replacements for them for much longer but the first time I tried to remove the old ones but they were so rusted on the inside thread to the stainless steel thread rods that I failed to remove any of them that time.
This time, I had prepared better beforehand. I had some highly concentrated phosphoric acid available and I knew that heating the bolts and hammering them might loosen them too.
Phosphoric acid makes red rust inert and will dissolve iron and steel but not stainless steel, which is an advantage because I needed to be rid of the old ball joints but needed to keep the stainless steel thread rods.
The first one I tried to remove was the hardest one. Although it had the advantage that I could remove the complete thread rod from the velomobile completely (4 of the 6 have their other ends attached in a spot where I cannot remove them), it took both acidand heat treatment to get the joint off.
But when it finally came off, I felt a big relief that I was at least capable of removing one and had some hope I could remove and replace them all before the end of the day.
The other two at this side only required some heating and hammering although I had to make sure I was not heating any part of the composite materials the velomobile is made of because that would cause it to catch fire. I used a pencil torch for heating so I had a lot of control but that also meant it takes some time to heat up.
After heating it sufficiently I would use two hammers (one mostly as an anvil) to hammer the nut-part of the joint. This part is cylindrical and about 3 cm long, ending in a hollow ball in which the other part of the joint can turn and roll.
After two rounds of heating and hammering them from all sides I'd be able to screw them loose. Mind you that takes some time and is in a very uncomfortable position as I have to do it on the velomobile lying on its side.
Then after going at this for about 4 hours in total, I had all the joints replaced and the wheels screwed back on but then I noticed that the wheels were not in the center of the wheel housing. It was decidedly more to the back.
The new ball joints either did not go as far on the threads or were just bigger. Strange as the thread sizes were exactly the same for connecting.
So I measured how much off-center the front wheels were and deciced to shorten the thread rods that kept the wheels in place in the forward/backward sense.
It turned out I'd need to remove 0.95 cm from one side and 0.85 cm from the other. I took out the calipers to mark where the rods needed to be cut and used the Dremel to make the cuts. Glad I have that thing, as doing that in that spot with a handsaw would have been hell.
After putting the wheels back on the centering of them looked a lot better.
And then I still needed to realign the front wheels so they would both point in the same direction. As it was at first, the front wheels were visibly diverging.
Luckily, I knew this beforehand and have actually done this twice before. What you need to do is clamp some straight metal profiles onto the front wheels tightly, then measure the distance between the profiles just behind the wheels and as far as possible in front of the weels.
Then you need to adust the "steering" ball joints (the ones that push or pull the assembly to make the wheels turn) so that the distance at the front and the back are as close as you can get them.
This is a slow process, as you need to first disconnect one joint (while the wheel is attached and it has this metal profile clmaped to it) turn it around a few times so it's more inward or outward, depending on what you want to do, and then completely reconnect it again tightly, measure the distances anew and repeat the process until your alignment is correct.
After four iterations, the wheels were now slightly converging. With one turn of the joint, it went from diverging to converging.
By then it was about 17:00 and but I also wanted to replace the rings that attach the front of the roof (it can be completely removed when you don't need it) because those were also rusting rather badly. I've had stainless steel replacements for them for a few months but hadn't gottten round to doing the actual replacement yet.
By that time I was tired and sore from working in an uncomfortable position so this took me more than half an hour where that should've been done in ten minutes.
The new ones have something of a "stalk" so the roof attaches about 4 cm higher at the front. I did that because the old rings would put the roof in a position where it was sometimes hard to see out from underneath it. The additional height at the front gives a much less obstructed view of the road ahead. Quite happy with how that turned out.
I did however, just realize that I made a mistake when I thought I'd reassembled things better than they were with the front wheel suspension so I'll have to revisit that on Sunday. Hopefully.
Tomorrow, Roos comes by to make recordings, Saturday is going to be the next radioshow, with Pasje and Roos as guest singers and we start early so we can rehearse some, so this is looking to be a busy time for the coming days.
And now it's so time for bed.
They were almost 20 years old and were pretty rusted as they were made of non-stainless steel.
One of them had actually rusted so bad at one point that it would not turn anymore. This alerted me to the fact I really needed to replace them.
I had had replacements for them for much longer but the first time I tried to remove the old ones but they were so rusted on the inside thread to the stainless steel thread rods that I failed to remove any of them that time.
This time, I had prepared better beforehand. I had some highly concentrated phosphoric acid available and I knew that heating the bolts and hammering them might loosen them too.
Phosphoric acid makes red rust inert and will dissolve iron and steel but not stainless steel, which is an advantage because I needed to be rid of the old ball joints but needed to keep the stainless steel thread rods.
The first one I tried to remove was the hardest one. Although it had the advantage that I could remove the complete thread rod from the velomobile completely (4 of the 6 have their other ends attached in a spot where I cannot remove them), it took both acidand heat treatment to get the joint off.
But when it finally came off, I felt a big relief that I was at least capable of removing one and had some hope I could remove and replace them all before the end of the day.
The other two at this side only required some heating and hammering although I had to make sure I was not heating any part of the composite materials the velomobile is made of because that would cause it to catch fire. I used a pencil torch for heating so I had a lot of control but that also meant it takes some time to heat up.
After heating it sufficiently I would use two hammers (one mostly as an anvil) to hammer the nut-part of the joint. This part is cylindrical and about 3 cm long, ending in a hollow ball in which the other part of the joint can turn and roll.
After two rounds of heating and hammering them from all sides I'd be able to screw them loose. Mind you that takes some time and is in a very uncomfortable position as I have to do it on the velomobile lying on its side.
Then after going at this for about 4 hours in total, I had all the joints replaced and the wheels screwed back on but then I noticed that the wheels were not in the center of the wheel housing. It was decidedly more to the back.
The new ball joints either did not go as far on the threads or were just bigger. Strange as the thread sizes were exactly the same for connecting.
So I measured how much off-center the front wheels were and deciced to shorten the thread rods that kept the wheels in place in the forward/backward sense.
It turned out I'd need to remove 0.95 cm from one side and 0.85 cm from the other. I took out the calipers to mark where the rods needed to be cut and used the Dremel to make the cuts. Glad I have that thing, as doing that in that spot with a handsaw would have been hell.
After putting the wheels back on the centering of them looked a lot better.
And then I still needed to realign the front wheels so they would both point in the same direction. As it was at first, the front wheels were visibly diverging.
Luckily, I knew this beforehand and have actually done this twice before. What you need to do is clamp some straight metal profiles onto the front wheels tightly, then measure the distance between the profiles just behind the wheels and as far as possible in front of the weels.
Then you need to adust the "steering" ball joints (the ones that push or pull the assembly to make the wheels turn) so that the distance at the front and the back are as close as you can get them.
This is a slow process, as you need to first disconnect one joint (while the wheel is attached and it has this metal profile clmaped to it) turn it around a few times so it's more inward or outward, depending on what you want to do, and then completely reconnect it again tightly, measure the distances anew and repeat the process until your alignment is correct.
After four iterations, the wheels were now slightly converging. With one turn of the joint, it went from diverging to converging.
By then it was about 17:00 and but I also wanted to replace the rings that attach the front of the roof (it can be completely removed when you don't need it) because those were also rusting rather badly. I've had stainless steel replacements for them for a few months but hadn't gottten round to doing the actual replacement yet.
By that time I was tired and sore from working in an uncomfortable position so this took me more than half an hour where that should've been done in ten minutes.
The new ones have something of a "stalk" so the roof attaches about 4 cm higher at the front. I did that because the old rings would put the roof in a position where it was sometimes hard to see out from underneath it. The additional height at the front gives a much less obstructed view of the road ahead. Quite happy with how that turned out.
I did however, just realize that I made a mistake when I thought I'd reassembled things better than they were with the front wheel suspension so I'll have to revisit that on Sunday. Hopefully.
Tomorrow, Roos comes by to make recordings, Saturday is going to be the next radioshow, with Pasje and Roos as guest singers and we start early so we can rehearse some, so this is looking to be a busy time for the coming days.
And now it's so time for bed.