rd400e front brake bleeding issues

[noonster]

Time as come to bleed my brakes. Back brake no problem bled straight away.

front brake.
Cleaned front master cylinder. striped it down,cleaned out small return hole. fitted new seal kit.
got new brake hose.
removed piston from brake calliper,cleaned everything up.pushed piston back in with fingers.
everything looking good.

The brake lever is spongy
Cant get enough pressure on lever.
got a small amount of brake oil coming out of bleed nipple tube ,but gets to bend in clear pipe then stops.

checked caliper piston it does not move.
removed top banjo bolt to master cylinder,put finger over hole and can feel some pressure. ( i thought it should go pop and a small amount of oil should flow )

i know master cylinder was clogged a bit with dried old oil,but i have clean it,put a small needle into small return hole,then blasters it a lll with compressed air.

Not fitted new seal in front,but i see no leaks,nice fit when pushing piston back in.

Back no problem.

Any ideas please noonster

[wangwang]

I use a syringe and pipe connected to the open bleed nipple to back fill the new hose with fluid, as it won't fill itself by pumping the the lever.

[Ozhammer]

Invest in a vacuum bleeder and you will wonder how you ever lived without it. I had the same issue with my 400G until I got one.

Rgds
Ozhammer

[paulsx]

Yep vacuum bleeder or just a large syringe will work ok

[noonster]

What I've also noticed,is a small amount of oil on my brake lever.Near the hole where the pinch bolt goes.

Is my new seal kit not sealing 100%.

could this be the reason why i can't get any pressure on my lever ?

I can i get round this, source another master cylinder.

Noonster

[wangwang]

If you're not too bothered about being original, something like this will work well. Has the mirror mount and same brake switch.
www.ebay.co.uk/itm/2014-yamaha-ybr-125-front-brake-master-cylinder-and-lever-/222280745314?hash=item33c0f70162:g:FgAAAOSwgApW~Tlu

[noonster]

thanks for that,but would prefer to be original

[muttsnuts]

Oct 13, 2016 20:23:25 GMT 1 noonster said:

What I've also noticed,is a small amount of oil on my brake lever.Near the hole where the pinch bolt goes.

Is my new seal kit not sealing 100%.

could this be the reason why i can't get any pressure on my lever ?

I can i get round this, source another master cylinder.

Noonster

should be no fuild near the lever unless you've dripped some on it !

sounds like its leaking past the seals, did you assemble it all using rubber grease ?

[paulsx]

I had this with mine. It was leaking from the o ring sealing the reservoir to the master cylinder and appeared at the pivot.