Bleeding front brakes

[HarryHornby]

Hi All,


I've finally got round to changing my master cyclinder so I can fit my new Chinese brake lever.


I've swapped the 2 over and now have the correct one on the bike (you guys will make a mechanic of me yet!  )


The lever is mega spongy, I say mega, there is no resistance at all so I need to bleed brakes.


I know about cabletying the brake lever to the bars, which I will try in the first instance BUT, do I loosen the cap on top of the cylinder to do this (to let any air out) or do I leave everything done up tight?

[darrsi]

I loosen the cap just a tad, BUT, if it's really spongy then it needs bleeding properly again, and then again until it feels firm.
Tying the lever back is a FINAL tweak over night.

[mick]

If you didn't drain off the lines and calipers you should be able to coax any air back into the reservoir by gently flicking brake lever back and forwards about half way. With the top off the master cylinder you will see air returning, carry on till it stops and you should get some pressure. then tie off brake lever over night, worked for me.

[HarryHornby]

Good call, Mick.  I hadn't drained the whole system, just emptied the cylinder and then swapped them over sharpish.


I did what you said and yep, air came to the surface, did that for a few minutes until no further air, now tied off.


We'll see shat happens, if still rubbish tomorrow I'll bleed properly.  That will be another learning curve for me :-)

[mtread]

Just asking, why did you have to change the master cylinder in order to fit the Chinese lever ? ........ I know, I shouldn't have asked 

[HarryHornby]

The one that was on the bike had a different fitting/lever.  The master cylinder looked exactly the same on the top, just the lever fitting was different, must have been fitter by the previous owner.

[mtread]

Oh ! Nothing wrong with the standard Fazer cylinder. You do wonder why people do that 

[joebloggs]

Oh ! Nothing wrong with the standard Fazer cylinder. You do wonder why people do that 

I would suggest it was probably replaced either after an accident or seal failure. The previous owner may have thought it the same item as it was visually similar.

[joebloggs]

I take it the lack of further posts means everything was OK this morning?

[unfazed]

The one that was on the bike had a different fitting/lever.  The master cylinder looked exactly the same on the top, just the lever fitting was different, must have been fitter by the previous owner.

Do you have a picture of the two.
Curiosity here 

What master cylinder was on it?
What master cylinder did you put on it????

[HarryHornby]

I took the bike for a ride this morning, brake was still spongy, ok for town riding but wouldn't fancy it at any speed,  so it looks like I'm about to learn how to bleed brakes! 


I'll try to get you some pics.  No idea what bike the old one was off.  There are some pics of the lever on the Chinese brake lever thread because I was confused why it wouldn't fit when I first got it.