Sram/Avid brake workshop for mechanics

Dan Hooper

· 17.06.2013

Photo: Georg Grieshaber

Sram/Avid brake workshop for mechanics | er

MTB disc brakes need to be serviced and bled regularly: Here you can find out everything about the most important service steps for Sram/Avid brakes.

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To prevent the disc brake from becoming a screeching pain in the arse, it needs a little care. BIKE mechanic Dan Hooper shows you how to maintain Sram/Avid hydraulic disc brakes.

Photo: Georg GrieshaberExpert BIKE mechanic: Dan Hooper shows how to bleed and service disc brakes. | t.

1st Sram/Avid brakes: Change pads

Iron on iron To ensure that it never comes to this, you should check the pad thickness regularly. Material, weather and braking behaviour determine the service life.

Remove the brake pads Remove the wheel, then first remove the locking split pin, then loosen the screw. Now remove the brake pads and spring from the brake calliper.

Pressing back the pistons If the brake pistons are stiff or dirty, you should first clean the pistons. Then press the pistons back into the calliper using the spreader block. To bleed the air, push the block all the way in and leave it there until the end.

Fitting the brake pads Whether old or new, you should only insert the brake pads into the spring at the very end after any other work has been carried out and put them back into the calliper.

Finally, do not forget to secure the brake pads with the 2.5 mm Allen screw (maximum 0.9 Nm) and the locking split pin.

5 Images

Photo: Georg Grieshaber

Time required: 5 minutes
Tools: 2.5 mm Allen key, possibly small, flat pliers

2nd Sram/Avid brake: Clean pistons

Move the piston into position Hold one piston back with an Allen key, for example. Carefully pump the lever until the other piston moves out of the saddle.

Cleaning the pistons Clean the pistons all round with a brush and brake cleaner. Finally, lubricate the pistons sparingly with brake fluid.

Wipe the pistons Pull a lint-free cloth through the brake calliper until both pistons are clean and free of brake fluid.

Finally, press the pistons back into the pliers using the expansion block. To bleed the air, push the block all the way in and leave it there until the end.

Bleeding kit for Avid, for example: two syringes, a 10mm and a 25mm Torx, a red spreader block and a bottle of DOT brake fluid

Syringes Robust syringes with stop and screw-on hose. The hose can be disconnected with a click valve.

Spreader block Conventional plastic block with bevelled edges to push the pistons apart. Alternative: Plastic tyre lever.

5 Images

Photo: Georg Grieshaber

Time required: 10 minutes
Tools: Brush, lint-free cloth, brake fluid, spreader block, flat screwdriver or Allen key, brake cleaner or alcohol

3. bleed the Sram/Avid disc brake

Aligning the lever Release the clamp on the brake lever and position it horizontally. You can also wrap a paper towel around the lever.

Filling the syringes Fill both syringes with three quarters of brake fluid each. Caution: Avid and Formula use DOT, but Magura and Shimano use mineral oil!

Place the syringe at the bottom Clamp a paper towel in front of the pliers. Unscrew the 10 mm Torx screw and screw the syringe completely into the thread.

Turn back the adjustment Turn the pressure point adjustment all the way back or out. Then tighten until the screw points upwards.

14 Images

Photo: Georg Grieshaber

Time required: 20 minutes
Tools: 10 mm and 25 mm Torx spanners, brake fluid, two syringes, spreader block, brake cleaner/alcohol, lint-free cloth, gloves

4th Qietsch prophylaxis

Aligning the brake calliper Quiet ringing, vibrating or irregular grinding can often be remedied by realigning the brake calliper and thus the brake pads. To do this, loosen the two fastening screws with an Allen key. Make sure that all nuts and spacer sleeves can also move freely. Now pull the brake lever a few times and then keep it pulled. Tighten the screws alternately with a long (!) Allen key. At the end, check that both pads are at the same distance from the disc.

Grinding the brake pads If the distance between the pads and the disc is very small, it helps to grind the pads at an angle. To do this, use a file to grind the pads a little on the side where the brake disc runs in. If the pads are "glazed", you can roughen the surface a little with fine sandpaper.

Tighten the spokes If the spoke tension in the wheel is very low, it helps to tighten all the spokes by half a turn. Then centre them.

Aligning the disc The brake disc can easily become deformed due to the extreme heat. Carefully (!) bend the disc back by hand at the grinding points and constantly check that it is running without grinding.

Finally, thoroughly wipe the brake discs with brake cleaner or alcohol. If necessary, rub the disc with fine sandpaper.

5 Images

Photo: Georg Grieshaber

Time required: 10 minutes
Tools: Brake cleaner or alcohol, fine sandpaper, file, Allen key, lint-free cloth or paper towel, spoke centring spanner

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TIP: Pressure point tuning with steel flex line

What to do if the pressure point is too spongy even after bleeding? Try braided steel brake lines. They stretch less than the standard plastic models and promise a crisp pressure point. The Goodridge lines can be retrofitted to all brake models for 50 euros.

Downloads:

Brake workshop (pdf)

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Sram/Avid brake workshop for mechanics

1st Sram/Avid brakes: Change pads

2nd Sram/Avid brake: Clean pistons

3. bleed the Sram/Avid disc brake

4th Qietsch prophylaxis

TIP: Pressure point tuning with steel flex line

Downloads:

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