Topic: 75 550F master cylinder

[Stumby]

So I rebuilt the master cylinder removing the fun cir clip and all. Now that I'm bleeding my brakes I can't get any pressure in the line. A few air bubbles came out at first, now none, so all the air appears to be out of the line. I don't see any leaks where the brake fluid might be coming out of. Any ideas why I can't get any pressure? Do I need to hold the bike upside down to get stubborn air bubbles out?

Thanks for any input,
Jeff
 

[supersport_CB400F]

If you don’t put the parts in the M/C in the correct order the same thing happens......... I had to do the circlip twice!   

[Stumby]

Yes, I found that out the hard way, but now they are all in the correct order. 

...and still no luck.

[supersport_CB400F]

List the parts you put in, I messed up with the rubber boot on the end of the spring………if your not getting any resistance in the brake lever and all the parts are in the M/C in the correct position  then  I reckon a quick fix is a new M/C off ebay 

[mack808]

Have you tried bleed the master cylinder only?   It can be done either by itself , or at the banjo bolt by wrapping carefully with rags while wrench attached and pumping, holding and loosening there. Also I have had master cylinders that would not bleed out using brake lever, but had to remove brake lever and i have a small tool I use to gently push on the piston directly, apparently some levers would not move piston completely and would never bleed out the system....

[Stumby]

Have you tried bleed the master cylinder only?   It can be done either by itself , or at the banjo bolt by wrapping carefully with rags while wrench attached and pumping, holding and loosening there. Also I have had master cylinders that would not bleed out using brake lever, but had to remove brake lever and i have a small tool I use to gently push on the piston directly, apparently some levers would not move piston completely and would never bleed out the system....

Thanks for the tips, I positive I have the parts in the proper order now. I suppose it's possible something may have gotten ripped having to perform this twice, but I don't think so.

Mack, I will give your idea a shot, I have two m/c right now, I may have switched brake levers on them. One of the units looks very slightly different then the other.

[750goes]

sorry to ask, but can anyone tell me what part number 224 is for??, and is it a must have item on reassembly..??

the reason I ask is my master cylinder had one, but when I removed the lever it crumbled into lots of pieces from being soaked in fluid over many years..

thanks

[supersport_CB400F]

sorry to ask, but can anyone tell me what part number 224 is for??, and is it a must have item on reassembly..??

the reason I ask is my master cylinder had one, but when I removed the lever it crumbled into lots of pieces from being soaked in fluid over many years..

thanks

I’m not sure what it’s for but I  have a spare M/C  if it’s in place you can have the part (400F) check your part #

[750goes]

biffta,

just checked the part number they are the same for the 400F and 750F being 45526-341-000, but I don't think it is worth posting it to Australia.

It seems to be just a pivot point and maybe this bush is just for wear, or maybe to ensure the lever when depressed actually pushes the piston in??? have to ask some brake specialists...thanks for the offer though..