How to fix a spongy brake lever
Work out why a brake lever feels soft or pulls to the bar: worn pads, sticky pistons, air in the system, old fluid or heat, and when a bleed is due on hydraulic e-bike brakes.
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- Difficulty
- Moderate
- Time
- 15 minutes to check, 1 hour with a bleed
Parts
- Disc brake pads (if worn)
- Mineral brake oil or DOT brake fluid (to match your brake)
A spongy lever feels soft, travels further than it used to, or pulls all the way to the handlebar. On hydraulic brakes the usual causes are worn pads, pistons that aren't moving freely, air in the system, or old fluid. On cable brakes it's usually cable stretch, covered in adjust mechanical disc brakes. Start with the simple checks here before you reach for a bleed kit.
Brakes are safety critical. If a lever has no resistance, or reaches the bar, stop riding and get it checked. Tektro says to stop using a brake whose lever gives no resistance and have it checked (Tektro owner's manual).
If you see fluid on the lever, hose or caliper, the system is leaking. Stop riding and get it serviced (Tektro owner's manual).
What you need
- A light to look at the pads, and hex keys or Torx keys to remove them
- A brake pad spreader or a plastic tire lever
- For a bleed: the brake bleed kit and fluid your brake uses
Steps
1Rule out heat
Long downhill braking can make the lever travel suddenly increase. Shimano says not to brake continuously, and to release the lever briefly if it fades (Shimano user manual, Shimano dealer manual). If the feel comes back once the brake cools, change how you brake on descents.
2Rule out storage position
Shimano warns its brakes may not work properly if the bike has been turned upside down, and says to test the lever before riding (Shimano dealer manual). Squeeze it several times and see if the feel returns.
3Check the pads
Thin pads let the pistons travel further. SRAM replaces pads once pad and backing plate together are under 3 mm (SRAM troubleshooting). Tektro's limit is 2.2 mm (Tektro owner's manual), and Magura's is 2.5 mm (Magura MT manual). See replace disc brake pads.
4Advance the pads
SRAM's fix for too much lever throw is to set reach fully out, pull the lever hard five times, then put reach back (SRAM bleed manual).
5Free sticky pistons
Dirt can stop pistons moving evenly. SRAM removes the wheel and pads, fits a pad spacer, squeezes the lever until the pistons meet it, pushes them back with a plastic tire lever, and repeats until they move smoothly (SRAM troubleshooting).
6Check the hose
Look for kinks, rubbing or damage along its length (SRAM troubleshooting).
7Bleed it
If the lever is still soft, there's likely air in the system or the fluid is old. Tektro blames a soft lever on low oil or air and fixes it with a bleed (Tektro FAQ). Magura bleeds when the pressure point is spongy or drifts (Magura MT manual). SRAM suggests a bleed for brakes over a year old, which also clears out water (SRAM troubleshooting). Use the guide for your brake: Shimano, SRAM, Tektro or Magura, or the general bleeding hydraulic disc brakes.
When a bleed is due
- After a hose is cut, replaced or disconnected, since that lets air in (SRAM bleed manual, Tektro owner's manual).
- When the lever stays soft after the pad and piston checks.
- On SRAM DOT brakes, at least once a year, more often with heavy use (SRAM bleed manual).
- Magura says Royal Blood doesn't age, so it needs no routine bleed (Magura MT manual).
Common mistakes
- Squeezing the lever with the wheel out and no pad spacer fitted. The pistons can push out, and Shimano says to see a dealer if that happens (Shimano user manual).
- Winding in reach or bite point to hide the problem. See adjust brake lever reach.
- Topping up with the wrong fluid. Shimano, Tektro and Magura take their own mineral oil, SRAM's Level, Guide, G2 and Code take DOT, and SRAM's Maven takes mineral oil (SRAM support). See mineral brake oil and DOT brake fluid.
Videos
When to get a pro
- The lever still reaches the bar after new pads and a bleed.
- Any leak, a damaged hose, or a lever that's been crashed.
- You don't know which fluid your brake uses.
- See when to call a pro.
Sources
- SRAM troubleshooting, sram.com
- SRAM bleed manual, sram.com
- Shimano user manual, si.shimano.com
- Shimano dealer manual, si.shimano.com
- Tektro FAQ, tektro.com
- SRAM support, support.sram.com
- Tektro owner's manual, tektro.com
- Magura MT manual, api.magura.com
- How to Bleed Hydraulic Brakes, Shimano Flat Bar Levers, youtube.com
- How to Bleed Hydraulic Brakes, Tektro and TRP Flat Bar and Drop Bar Levers, youtube.com
Stuck after these checks? Find a shop near you.
If these steps didn't fix it, find a shop near you in our partner network. For battery or wiring trouble, look for shops marked Battery and electrical.
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