On the first pull of the lever I get classic air in the system sponginess but if I do three or four quick pulls the brake is tight as you like.

I’ve bled the brake system twice now. Once from lever down to caliper and just done it from calliper up to lever with a syringe. No change at all.

Anyone else suffered this? It’s SLX system Mk1.

I’ve found that to be pretty standard with mineral oil brakes. I had it with Magura rim brakes and I get it with Shimano disc brakes. I’ve never found a reason why it does that. I concluded that mineral oil takes a few pumps to “warm up”. After that its rock solid. Only thing I would suggest is changing the pads. I find the pumping thing only happens when the pads a half worn.

Never had it with DOT fluid brakes. But Shimano brakes are so good I cannot think of why anyone would bother with anything else.

Just sounds like air in this system.

Air & sometimes dirt trapped in the system, be patient do a “bubble bleed” it is a faff but you will get it right in the end!

Another tell tale sign is when you put the bike in the wheelie position and the brake lever pulls back to the bar but is fine when flat!

Sometimes you get lucky with Shimanos and the air moves to the top of the lever/master cylinder all by itself and you can get away with just topping the reservoir off 8)

Avids I lie the bike down on it’s side! Shimanos level lever, flat position for front and wheelie position for rear, it matters!!

Keep bleeding keep keep bleeding.

I shortened my hose last night then bled as they were spongy before anyway..
Rock hard with the bleed block in place so popped the new pads in and fitted the wheel….spongy lever again!!

Try topping up the system with fluid after fitting the pads and wheel. Use our 5 Min Shimano Mini Bleed technique to get the desired result.

http://www.epicbleedsolutions.com/blog/5-minute-shimano-mini-bleed/