Bleeding rear brake

[richard100t]

I replaced the rear brake line & everything is in place. Washers are where they are supposed to be. I cant get the pressure to build I disconnected the master cylinder end of the line to make sure the pump worked & I am getting pressure when I apply the brake. The fluid doesnt seem to want to travel from the reservoir thru to the line. I bought a speed bleeder from MG cycle but no luck with that yet. (I mean I got it & all but its no help)

[Paul Minnaert]

What I do is: I have an extra cover for the fluid holder. I made a hole of 20mm in it. Then I fill it up, through the hole I push the fluid to the caliper that is open at one side. The rubber thing is still in there, I use that to push on. When the reservoir is empty, I fill it again and then the other airscrew on the caliper. Works fine, font and rear.

I figured this out when my old tonti would't do it from rear to front with the integral system.

[Martin Barrett]

Try raising the calliper (above master cylinder) so that the air goes upwards and out,

on the bleed nipple have a piece of tube that goes into a jar with a bit of brake fluid in it. You will see if pushing air out and will help prevent suck back of the air. I've used bleeding kits before and still had to shut the bleed off for each pump.

you may need to enlist the help of another person one to press and hold the brake, one to do the bleed screw.

 

Oh and chock the pads, and keep the master topped up.

 

It can be a real bugger when you've got air in the lines and not just old fuild.

 

If still doesn't work try with a normal bleed nipple first and then replace the speed bleeder. I did read some where about a deffective one Wildguzzi I think?

[richard100t]

Hmm I'll try pushing on the rubber thing & see if that forces the fluid thru to the caliper end. I have the bleed nipple open but nothings coming thru yet. I'll try Martin's advice later only because I'm lazy & I dont want to pull the wheel off lol

[Martin Barrett]

Try the other bits first , then take the caliper off its mount as a last resort. I had mine off when I did a pad change and clean, but can't remember if there would be enough flex in the hose to lift up as I pulled it down and forward to clean.

[richard100t]

Good news! I removed the bleeder nipple & covered the hole with my finger. I could feel pressure build up & when I let go air & fluid bursts out. The fluid also gets warm? Still unsure why I cant get brakes but I know I'm on the right track. I'll have my maintenance man friend give me a hand & I'm sure we'll get it right.

[orangeokie]

Good news! I removed the bleeder nipple & covered the hole with my finger. I could feel pressure build up & when I let go air & fluid bursts out. The fluid also gets warm? Still unsure why I cant get brakes but I know I'm on the right track. I'll have my maintenance man friend give me a hand & I'm sure we'll get it right.

56004[/snapback]

 

I had this same problem with my aprilia Falco when I installed new brake lines. The final solution (most difficult) worked. Like has already been mentioned, you have to take the rear caliper off and hang it higher than the master cylinder. Put a shim between the pads to keep them from collapsing. The air bubbles will then all rise upward. With your speed bleeder you will shortly have all the air out of the line and good rear brake pressure.

[richard100t]

I had this same problem with  my aprilia Falco when I installed new brake lines.  The final solution (most difficult) worked.  Like has already been mentioned, you have to take the rear caliper off and hang it higher than the master cylinder.  Put a shim between the pads to keep them from collapsing.  The air bubbles will then all rise upward.  With your speed bleeder you will shortly have all the air out of the line and good rear brake pressure.

56005[/snapback]

I'm starting to see the light I guess I'll just have to remove the rear wheel & get the caliper up in the air. Otherwise I'll probably need a pressure system to bleed it.

[orangeokie]

I'm starting to see the light  I guess I'll just have to remove the rear wheel & get the caliper up in the air. Otherwise I'll probably need a pressure system to bleed it.

56012[/snapback]

 

Even a pressure system didn't work for me until I used gravity. Went through two bottles of brake fluid with a Mighty Vac before finally breaking down and doing it right. For some reason that rear master cylinder just holds on to those air bubbles.