Having been fortunate enough to have access to the required Avid Bearing Replacement tool I decided to replace the VERY seized up bearings in my Avid Arch Supremes.
The bearings are 688HZZ 8mm x 16mm x 5mm
8mm ID
16mm OD
5mm thick
There are 2 bearings per brake arm so a total of eight bearings are required.
Here are the brakes, one of the new bearings and the bearing tool.
The bearings are actually housed in a removable bearing sleeve which is removed with the special Avid bearing tool:
Once the bearing sleeve is removed each bearing must be tapped out from the inside out. There is a short 8mm ID spacer located inside the bearing sleeve between the inner surfaces of teh two bearings. It must be nudged a little out of place in order to be able to tap out the old bearings:
Then place the bearing housing in a crescent wrench:
Then tap out the bottom bearing with a hex socket or something similar:
To tap out the second bearing I put the bearing sleeve the hex socket and used a 17mm box wrench on top of the sleeve.
A few firm taps and the second bearing was out. You can see the little 8mm spacer here too.
Repeat this 3 more times for the other brake arms and it's time to put in the new bearings.
To install the new bearings I made a little bearing press from an 8mm stem bolt and some wedges. I threaded the wedge on backwards so I could rest the new bearing against the flat surface of the wedge.
Then the bearing:
then the spacer:
then the bearing sleeve:
Then a second wedge or an 8mm nut if you have one:
Then tighten the whole stack down gently:
until the bearing is flush:
tada:
After doing one bearing and determining that the flat surface of the wedges were applying some undue pressure on the inner bearing surface I decided to use some washers that would transfer all compression forces to the outer bearing race:
I think this provides a much gentler compression and the bearing spun absolutely smoothly after this slight modification.
Bearing sleeves ready to be reinstalled into the brake arms:
Freshly serviced Avid Arch Supremes ready for riding.
The bearings are 688HZZ 8mm x 16mm x 5mm
8mm ID
16mm OD
5mm thick
There are 2 bearings per brake arm so a total of eight bearings are required.
Here are the brakes, one of the new bearings and the bearing tool.
The bearings are actually housed in a removable bearing sleeve which is removed with the special Avid bearing tool:
Once the bearing sleeve is removed each bearing must be tapped out from the inside out. There is a short 8mm ID spacer located inside the bearing sleeve between the inner surfaces of teh two bearings. It must be nudged a little out of place in order to be able to tap out the old bearings:
Then place the bearing housing in a crescent wrench:
Then tap out the bottom bearing with a hex socket or something similar:
To tap out the second bearing I put the bearing sleeve the hex socket and used a 17mm box wrench on top of the sleeve.
A few firm taps and the second bearing was out. You can see the little 8mm spacer here too.
Repeat this 3 more times for the other brake arms and it's time to put in the new bearings.
To install the new bearings I made a little bearing press from an 8mm stem bolt and some wedges. I threaded the wedge on backwards so I could rest the new bearing against the flat surface of the wedge.
Then the bearing:
then the spacer:
then the bearing sleeve:
Then a second wedge or an 8mm nut if you have one:
Then tighten the whole stack down gently:
until the bearing is flush:
tada:
After doing one bearing and determining that the flat surface of the wedges were applying some undue pressure on the inner bearing surface I decided to use some washers that would transfer all compression forces to the outer bearing race:
I think this provides a much gentler compression and the bearing spun absolutely smoothly after this slight modification.
Bearing sleeves ready to be reinstalled into the brake arms:
Freshly serviced Avid Arch Supremes ready for riding.
