Steering Head bearings

[oconnor]

Hi
I have just been given a 1951 Model 18 in several boxes, first job was to assess what is and isn't there by doing a dry build,95% complete.
The first problem seems to be the steering head bearings, I have a full set of top and bottom mostly new ball bearings, and the bottom and top races on the stem and header look to be in good condition, and can't be fitted the wrong way round as they are of different internal sizes.
My problem is the races fitted to the frame appear to be worn out, the bottom stem race fouls the frame before the balls make contact.
Two questions;
1.Are the frame races available?.
2.Can the head bearings be converted to taper rollers?.
Many thanks any help appreciated.

[Andy.S]

Hi Michael
club spares have them 000806 is the part number https://www.amoc-parts.com/store/comersus_listItems.asp.
Everything is possible but i haven't seen taper bearing fitted , but no doubt someone with more knowledge will be along shortly to fill you in with more information.

[Duncan]

Hi
I have just been given a 1951 Model 18 in several boxes, first job was to assess what is and isn't there by doing a dry build,95% complete.
The first problem seems to be the steering head bearings, I have a full set of top and bottom mostly new ball bearings, and the bottom and top races on the stem and header look to be in good condition, and can't be fitted the wrong way round as they are of different internal sizes.
My problem is the races fitted to the frame appear to be worn out, the bottom stem race fouls the frame before the balls make contact.
Two questions;
1.Are the frame races available?.
2.Can the head bearings be converted to taper rollers?.
Many thanks any help appreciated.

AMC frame races are curved on the back to correspond with the frame, I would imagine serious engineering would be required to fit tapered rollers.

Any chance of a picture of the lower race fouling, it may be that something is non standard? If you assemble the lower race on the stem, put the ball bearings in and place the lower frame race on top can you insert it into the headstock?

[mdt-son]

As Duncan wrote, bearing races are curved at the OD, mating with the headstock and steering lug bearing seats. If these seats are in good shape, fitting new races is your best option. I suggest glueing the bearing seats to the headstock, preventing them from moving around, as they might be inclined to otherwise.
However, if your frame's bearing seats are worn or deformed, I wouldn't hesitate doing a bearing conversion to an angular contact ball bearing. These are small and much easier to accomodate than taper roller bearings. Some engineering and maybe some CAD work will be required for a successful result.
There was an article in "The Jampot", in the late 90's I believe, which explained how to mill the bearing seats using simple tools. Using the database of articles published, you will be able to retrieve the article.

- Knut

[oconnor]

Thanks Away for a couple of days will post photos on return

[oconnor]

Had a chance to revisit "head bearings" or lack of, I think the previous owner who stripped the bike removed the upper and lower bearing seats,
when I re-assembled I assumed the curved surfaces to be the bearing seats ,when in fact they are the inserts the seats sit on, have ordered new seats.Hold my hand up to that one.

[magnusk750]

There is an article in Jampot circa 1991-1992 about fitting, I think Fiat 127 wheel bearings, as taper roller bearings, but quite a lot of machining involved.

[ChrisTheChippy]

An easy mistake to make. The PO of my rebuild project actually left out the bottom race altogether and lost a lot of the ball bearings so averaged it out between the bottom and top bearing positions !
When I stripped the forks to rebuild them there was so much grease in there it took me a while to figure out what was going on. I just hope he never rode the bike like that.

[JEAN-NOEL]

Hello Michael,
I did the conversion with taper rollers bearings, I think in 1996. It was a straight forward operation, without any machining. But I don't remember Timken's reference. Old external and inner races were exactly of same dimensions than OD & ID of bearings. My forks are Roadholder ones. I don't know if the races are the same on Teledraulic.

[mdt-son]

Jean-Noel, you have a 1964 type headstock. The design is completely different to the 1947-63 type.

- Knut