Kona chose a mechanical disc brake brand called Avid codenamed BB5 for their ute and mini ute cargo bike range. This brake system brand is a mechanical design meaning the same mechanical arrangement as any garden variety rim brake bike from the handle bar to the wheel caliper brake arm anchor points.
In dealing with the Kona ute and mini ute braking system we will be concentrating on the Avid BB5 braking system. When you squeeze the handle bar lever only one pad is pressed against the disc. A pad on the other side of the rotor ( the wheel spoke side ) is fixed. For efficient breaking the fixed pad needs to be adjusted close to the disc. If to far only the moveable disc is not pressing the rotor properly resulting in paternally distorting it causing only one side pressed on it causing spongy and ineffective stopping power. Another problem can also cause the same problem if the cable anchor securing the inner wire cable to the caliper brake lever has been dissembled and reassembled can potentially cause brake efficacy problems.
A bend in the inner wire cable at the anchor point on the caliper lever can cause spongy braking. If this is the case the cable has to be disassembled and repositioned so the cable is going straight into the cable adjuster.
Adjustment is provided on the caliper bake arm and handle bars. If the handle bar adjusters are adjusted to far out causes a fair bit of bending stress on the threads when squeezing the brake levers striping them te adjuster threads. Squeezing takes it's tool. So too to a lesser extent the adjuster on the caliper. To prevent and solve this problem problem screw the adjusters all the way back to nil. We need to readjust the bake arm anchor bolt position.
The bike can either be left up right on it's wheels or turned upside down resting on the seat and handle bars it's up to you. Professional workshops have bike stands everything chest height both wheels off the ground. In a backyard situation with the bike upside down the wheels at lest are free to rotate when adjusting the pads to the disc. ( Or the rotor ).
An Allan key unlocks the anchor bolt holding the inner cable to the caliper brake arm. The arm will spring back to maximum distance.
Make sure to locate the wire so it going straight into the adjuster. Depending whether left or right handed and looking at the bake arm the bike upside down or if chosen the right way up, pull the tail of the wire to maximum taking up the slack and with the other hand free to push the bake lever moving the pad close to the rotor. Give a little extra to compensate for the taking up slack cables tend to do when retightening. You will have a bend in the cable again bringing you back to square with effecting brake performance again. Not only that but causes extreme maximum handle bar adjustment problems again. Don't allow run out of adjustment or every time you squeeze the handle bar levers or will stress the threads again. Leave the handle bar adjusters screwed right back to nil. So to the caliper brake arm adjuster.
As you finger tight to hold it letting it free you will observe the cable takes up the slack pulling the extra closeness of the pad away from the rotor. Turn the wheel round to check you haven't over compensated for cable slack movement the pad is too close to the rotor. If it is a bit close for your taste you can fine tune from here. Fine tuning is the key to efficient braking. Undo just enough you can slip the cable a bit a retighten enough and double check on the wheel is free to spin.
Spin the wheel gripping the handle bar levers so the wheel jambs instantly to a stop. As you hold the lever the wheel should be jammed in position. If this does not happen follow the text step
Turn you attention on the spoke side of the caliper. In the center is Allen key bolt. This adjustment adjusts the fixed brake pad. An Allan key through the spokes turning inward adjusts the fixed pad towards the rotor and screwing outwards away from it. Screw inwards finger tight on the rotor squeezing the handle bar lever checking the wheel is jammed by the pads.
Next gently unscrew outwards a little so the wheel is free to turn and spin freely. To far out will cause the spongy braking problem all over again. When the handle bars are squeezed you can actually drag the wheel against the squeeze of the handle bars. Adjust gain retracting back inward a bit. When you squeeze the handle bar lever again the wheel should suddenly jamb stop and can't move while the brakes a squeezed. When you release the levers the wheel will be free to spin freely.
When satisfied don't wrench the maximum tight the anchor bolt or you will start the processes of striping threads. Just a light wrench tight is enough.
When adjustment like this is carried out the original adjustment is disturbed and the brakes have to be run in again. This is usually done in time during normal braking procedures while riding. A popular trick to help hurry up the processes is a bit of sanding on the pads. This is usually a bit of a discretion on your part if the pads look a bit to warn down a bit for that. It is a decision processes based on your own judgment how much they can take.
As you use your bike you will notice braking power is satisfactory even great. Never the less in time you will experience a slack growing. It is a normal sigh of time for the routine maintenance procedures of adjust the slack cause by the normal ware stretching of the inner wire cable and on the pads.
After a while when the pads get to be a bit thin noticeable adjustments of the brakes the caliper brake arm gets close to the adjuster as the brake pads get closer and closer to the rotor eventually there will be no more margin left left in the pad surfaces causing the inside brake arm lever mechanism from working properly to work the moving pad. Time to replace.
Replacing the pads.
When you come to remove the cover small parts can easily fall out and get lost. Or at lets spending all your time looking for them that could fall anywhere. It pays to put a catcher tray in direct line the parts may fall caching them so you don't loose them.
You don't need to remove the inner cable from the caliper anchor bolt. This can be ignored. Instead concentrate in unscrewing the fixed pad adjuster bolt out as far as it can go. You will find when you remove the wheel the pads won't interfere catching on the rotor. The wheel will come off just like that. The same Allen key that fits the cable fixed adjuster will fit the two bolts on the wheel side of the caliper. Don't be shy to put some weight on them to undo. But don't be rough unscrewing because of the aluminum threads. They must be with drawn out dead straight.
Once the bolts are withdrawn the cover comes off, one or both pads, along with the spring may fall into your catcher. Remember you are handling the brake pads from now on so your hands should be pristine clean to insure you don't transfer oil and crease to the oil absorbing pads and rotor.
Examining the spring is a “V” shaped steel spring as seem in the left picture each tip crumpled each end a "u" shape hook that fits in a slot in each pad. The spring is effectively sandwiched between them.
Notice the hole in the center of the pad. This refits to the corresponding peg in the covers. Make sure you reassemble the pad hole in the corresponding pegs in the calliper covers properly.
Reassembly is tricky as it is a bit fiddly. Fit a pad color side into the corresponding recesses in the caliper cover fitting the spring in the corresponding pad slot as shown by the left picture. Make sure the center hole is fitted in the peg properly
Correspondingly fit the other pad color inwards the cover recess guiding it hooking the tip of the spring into the hook in the slot of that pad.
Line up the cover to the threads. Careless fitting of the two bolts into theses threads here is the major cause of stripping the calliper threads rendering the bolts useless. Screw the bolts carefully dead straight with only fingers. Never force them with the spanner if they feel a bit tight. Carefully withdraw and jiggle the cover a bit so the bolts can finger screw with out any grinding tight feel freedom of movement.
The final tighten of the bolts is another area will strip the caliper threads. Don't wrench thinking maximum tightness. A light tug they can't and no more.
The next step is the refit the wheel. All that is need is to screw back the fixed pad back in position close to the rotor as already described in adjusting it.
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