Hello. I was replacing the rear master cylinder piston on a 125 txt I picked up for my son and it wouldn't bleed at all afterwards. After checking some of the threads here I pulled it back out and put a syringe on it to force some fluid through but it seemed to be blocked.

After taking the piston back out it appears to be a different length to the original (longer) and the seal blocks the port from the reservoir once the circlip is installed. Is it me being daft or is the piston wrong? It came in the proper kit for this master cylinder.

 

 

My suggestion to you is to replace the master cylinder. Quite often it is a waste of time and money putting in the repair kit.

I give up.

 

I've replaced master cylinder, rebuilt the calipers, pushed fluid through from both ends, vacuum bled, lifted the back of the bike 3 ft in the air, left a tube with fluid on the nipple overnight.

 

Still no pressure on the pedal. I've bled a lot of brakes over the years but this is ridiculous.