building pressure brake master cylinder

[Djfob]

For the life of me I cannot build any pressure in the brake lever to bleed the brakes. Brand new nissin brake master, banjo bolt and two copper washers, steel braided line, caliper hard line, bleeder, caliper seal and phenolic piston.

All brand new parts with pads. The pad on the piston side was so tight I had to tap it in. Not sure if that matters.

 

[SONICJK]

Is your bleeder valve closed? It has to be closed to build pressure before you bleed

 

[Djfob]

Yep the bleeders were ckosed. I ended up using a syringe to bleed from the bleeder up to the master. Brakes have pressure now but the new pads seem to drag.

 

[rockcitycafe]

what size is the new master cylinder and what size was the stock one

 

[Djfob]

Both were 14mm. Pressure and brakes feel fine now with the syringe method. Just have to figure out why the pads drag and catch on certain spots on the rotor.

 

[rockcitycafe]

sounds like one of the calipers is too tight, you mentioned having to hammer it in?

if you can't push it in by hand, it's not going to retract from the disc on its own, they rely on the seal flexing to move a few thousandths back from the disc when not under pressure

 

[Djfob]

I had to tap the brake pad in, the piston I can retract pushing it with my hand. I'll take a dremel to the page to add some clearance.

 

[o1marc]

Here's a trick I learned when I ran the brake department of Rebco Racing Enterprises. This was for racecar calipers but should be the same for any caliper. Our standard caliper seals were square like most motorcycle seals. When racers complained of pad drag when the brakes got hot we would replace the square seal with a round one. The round one would retract more than the square one and solve the problem. If you had to tap the pad in, there lays your issue. it should move freely, sand the pad where it is rubbing till it moves freely and you should be good to go.

Doesn't anyone read their posts before submitting them?

"I'll take a Dremel to the "page" to add some clearance."

"Sounds like one of the "calipers" is too tight"

 

[Djfob]

Damn you auto correct lol. Dremel the pad.....