Bleeding brakes

[Dr. Scooter]

I am having trouble bleeding the the rear brakes front brake master cylinder

[Shaka]

What's going on?  Are you not getting all the air out?  What are the symptoms?

[Dr. Scooter]

I have tried manually bleeding, bleeding with a vacuum pump, the front brake is awesome. The rear I cant get to bleed out. Its still mushy and I am not comfortable to ride it yet

[Shaka]

You probably just have an air bubble trapped somewhere along the line.  Try lightly tapping on the caliper, line, and master cylinder with a wrench while bleeding to "dis-lodge" any bubbles along the way.

[Dr. Scooter]

I have a feeling it is in the relay valve

[Shaka]

Very well could be.  Just try tapping on everything, also quick little flicks of the lever will all help to dis-lodge trapped air bubbles.

[Hoolander2]

Arkie, you prob already know this but I think there's supposed to be a bleed nipple on the delay valve too.

Think you have to take off front plastic to get to it. 

I still think the service manual is unclear about bleeding that delay valve.  Seems to say that when you bleed the front right, the delay valve gets bled at the same time.  Or maybe it's saying that you have to bleed it at the same time.  Don't know for sure.

It may be the culprit. 

[Dr. Scooter]

It says bleed the relay valve then the rear brake then the right front. I am trying to bleed it manually tonight maybe just maybe it will work

[Dr. Scooter]

Ok now for a strange one I turn the cam to postion 1 and the brake feels great turn it to postion 4 and it pulls all the way in. Also why is the cap have a ring all the way around with two open spots

[Hoolander2]

I'm guessing for sure now. . .  could something be bent like the brake lever or the cam?  That IS listed as one of the causes of brake drag. 

Somebody with experience help Arkie on this. 

[Shaka]

I'm just guessing on your particular brakes, but the cam may adjust the pad contact point.  These typically work by changing the volume of the master cylinder.  It may be normal to have it nice and firm on 1 and squishy feeling on 4.  That cam is to adjust the modulation at the lever for that purpose.  Some people like their brakes real firm and others a bit squishy.  Like I said I don't know how your brake work, but I work on mountain bikes for a living.  The higher end mountain bike brakes have this feature.  What position was the cam on when you bled the brakes?  I've found on mt. bikes if you bleed them on the squishy setting, they get nice and firm when you flip it back to the firm setting.  This is because you get the system full of fluid to max capacity on the squishy setting.  When you switch to firm it pumps extra fluid to the calipers to move the pistons closer so that at the lever you have a shorter throw and firm contact. 

[Hoolander2]

Arkie.  I tried different cam settings on my brakes today.  There was no difference in the feel or travel of the brake lever no matter what position.  You get it working right yet? 

[Bryan]

I've always thought that the cam action on the levers is purely to adjust the position of the lever, to accomodate the different size reach of the hands and had no effect on the action of the brakes. The same pressure on the lever at the two extremes of the cam setting will result in the same force on the brakes the only difference would be in whether the lever is closer to the bar for smaller hands or further from it for the bigger hands. Perhaps someone could scan the relevant pages of the workshop manual and post them I know I would like to see a bit more detail about this process and I haven't managed to get a manual yet. Keep us posted and thanks this is very important information to know. Regards from Durban RSA.

[axy]

I've always thought that the cam action on the levers is purely to adjust the position of the lever, to accomodate the different size reach of the hands and had no effect on the action of the brakes.

... and you are right.

[Dr. Scooter]

Then on that note I still have air in the system I need to find