I always wanted to make a video but never got to it. Instead below the Dr. Theses.....
My press is 10ton, I would consider that as a minimum.
Here is how I do it,:
1) Take the circlip out which holds the bearing in place
2) Rest the upright on 2 plates allowing the hub to get pushed downwards. The 2 plates might be around 10mm thick, one on the left and one on the right between the hub and the upright.
3) Use a diameter 34.9mm piece of steel to push the hub out. That requires usually 2-3 tons
4) Turn upright around onto a inner diameter 65.5mm tube, Use a diameter ??60mm not sure tube to press the bearing out. The bearing is getting pushed into that diam. 65.5mm tube. This is the toughest part and requires around 9-10 tons. It can be a challenge if the bearing came apart when the hub got pressed out. Some bearing separate, some types do not. In some cases I had to grind a flat spot into the bearing before pressing it out. That applied to a bearing which came apart.
5) If the bearing came apart, there is an inner race stuck to the hub. There are pullers to pull that inner race off the hub. I got mine at McMaster and had to modify the arms slightly to get behind the race.
6)Clean or sand the hub bearing seat, measure, should be diameter 35.010-35.020mm. Replace hub if too small.
7) Clean Upright ID Bearing seat- I never measure it, It usually does not wear much.
8) Put new bearing and hub into freezer for 6+hrs.
9) Use wife's crock pot and heat up the upright, 100-120C upright temp. Takes around 1-2hr.
The thermal fit is easier on the parts and helps aligning the parts somewhat. Be quick to keep temp differences as big as you can before the 2 parts are fully seated.
Also use a mix of 90% Kerosene and 10% 2 stroke oil to lube all the parts in order to mitigate galling. Avoid using lubes which have wax, that would reduce the retention value and support fretting.
10) Put hot upright onto press and push the ice cold bearing in with press, only use a tube which is diam. 64.9mm, must not push the bearing into upright through the inner race. Make sure it fully seats, I usually go up to 8 tons.
11) Put upright with pressed in bearing into crock pot. Make sure you do not go over 130C, bearing steels do not like it too hot, same with the grease and seals.
12) Put the ice cold hub onto the press, upside down. Have a diam. 40mm round steel on top of the inner race of the bearing (which is in the upright). Press the bearing onto the hub, usually it just goes on together by gravity, due to the thermal effects.
All the tubes and round steel pieces I made on a lathe, that way they are true and align parts well during the press operation.
13) Put the circlip back into the upright.
I never mess with bearings, like grease them- this is not a trailer
.
Usually I spin the hubs by hand between weekends, if the bearing goes bad it takes different torque values to turn it- low high torque about 30x per revolution.
At the track I have 2 different uprights with fresh hubs and bearings which I can replace any time. I use FAG roller bearings, they are rubber sealed, The SKF bearings are steel shielded and loose the grease. I guess ball bearings are fine, I never used them.
Shoot me a message if you need hubs, I always have a few extra.
Posted: Mon Aug 09, 2021 6:53 pm