Author Topic: ACS Boa 10mm to 6mm spindle swap (Read 12339 times)

ED209 · « **on:** September 06, 2013, 06:47 PM »

Heres one for all those who scooped a bargain Boa @ MK

ACS Boa 10mm to 6mm spindle swap

Important - before you start! make sure you work over a cloth / blanket as 68 tiny ball bearings will fall out as you take the brake apart!!!

Here we go ...

- Remove the front 'sealed mech' cap with your fingers. If the tiny threaded bit the cap screws onto stays in the brake and you need it out theres a tiny allen key head on the end of it to unscrew it with.

- Unscrew the mounting nuts and rear spring holder.

- Hold the front of the spindle with a spanner whilst slotting a small allen key into the holes in the rear lock nut and unscrew ( theres no allen head in those holes ... you just use it as a lever ) - REMEMBER to do this SLOWLY and over the cloth / blanket as all the ball bearings in the brake will fall out as it becomes loose.

- As you carefully remove the arms from the spindle REMEMBER the direction of the seals and the order that they are mounted in. All the seals can be re used in the spindle swap.

( I wanted to strip the arms on my brake so I popped them in a bit a Synstrip and gave them a light polish )

- Divide the bearings into 4 piles of 17. If the bearing races have dropped out of the brake arms use a blob of grease to stick them in again.

- Using a good amount of grease place the bearings back into the races on each side of each brake arm ... if you have a greasy finger this is useful for picking the bearings up. Get them roughly in position then use the small allen key again to position them... smooth the grease over to finish. This is fiddly but not as bad as it seems :-)

- Once you have done this for both sides of the brake CAREFULLY remount the new spindle getting the seals in the right position and right way round. Do the final tightening GENTLY as the bearings can easy pop out or you can mash the seals ... slow and steady :-)

- Tighten everything up and again screw the spring mount back in.

- Polish up to clean up any remains of the grease.

Job done :-)

pkripster · « **Reply #1 on:** September 06, 2013, 06:49 PM »

ask costa

harris · « **Reply #2 on:** September 06, 2013, 06:49 PM »

lots of grease,they try to fall out not hard just tricky.done loads

Dannywhac · « **Reply #3 on:** September 06, 2013, 06:56 PM »

Quote from: harris on September 06, 2013, 06:49 PM

lots of grease,they try to fall out not hard just tricky.done loads

x2

If it's a used one, don't start to take it apart until you've got it over a bowl - them bearings shit everywhere if they're not greased. When you undo the retainer nut on the back, push the front of the axle (holding the arms in your fingers) so bearings that fall out will only come out from the bit of the brake at the rear, and from where you want them to

That and curse as you realise the placcy bearing seals are fooked. They'll still go back together though. Built to last them Boas

ED209 · « **Reply #4 on:** September 06, 2013, 07:05 PM »

its a new one Dannsta.

How do you get the retaining nut off the back? ... the one with the holes drilled in it?

Dannywhac · « **Reply #5 on:** September 06, 2013, 07:12 PM »

Thats the fella - I've always used (after unscrewing the placcy front bit) a set of mole-grips on the front nut, then use either a small allan key/jewellers screwdriver in the holes on the back nut (failing that another mole-grip) on the rear nut. Basically hold the front of the Boa in place and unthread the rear nut

GavinDavis · « **Reply #6 on:** September 06, 2013, 07:34 PM »

Its not too bad a job to be fair Ed, I did it to a boa that I bought off Olly.

One thing I will add though in addition to the bearings going everywhere.....i think there are 68 bearings in a boalol, is to remember which way the seals go round on top of the bearings.

I made the mistake of getting it all back together, tightening it up only to watch the seals buckle and the bearings tried to exit from all angles lol.

Be on guard.....and keep your cool.....2 very important factors for the job lol

chubby · « **Reply #7 on:** September 06, 2013, 07:39 PM »

Another tip is don't attempt is while looking after an 18 month old, it needs full concentration first time round

GavinDavis · « **Reply #8 on:** September 06, 2013, 07:41 PM »

Quote from: chubby on September 06, 2013, 07:39 PM

Another tip is don't attempt is while looking after an 18 month old, it needs full concentration first time round

Very good point! Lol

ED209 · « **Reply #9 on:** September 06, 2013, 08:34 PM »

thank you one and all ... off now to tinker

chubby · « **Reply #10 on:** September 07, 2013, 01:23 PM »

Quote from: ED209 on September 06, 2013, 08:34 PM

thank you one and all ... off now to tinker

you done it yet

ED209 · « **Reply #11 on:** September 07, 2013, 01:40 PM »

Stripped it down.
Stripped the paint off the calipers and gave them a light polish.
Waiting for the new spindle off Costa!
Full photo story to follow.