How do you bleed a disk brake?

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Anyone provide the numpty guide so I can do it on my prostop?

I would like an appropriate 'hackers' methodology/guide as I dont really want to spend time doing it properly. ;)

Those that came to Cannock saw that the pads aint retracting very well after Gump went and broke it. John etc have said it needs bleeding.

Has it got air in the system or something? :?
 

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Can't comment on your actual problem, but bleeding should be the first step.

Slightly off topic, if you are using normal car brake fluid in the brake and the bike doesn't get much use if you are going to do a rebuild its worth changing to silicon brake fluid.

I don't know the science behind it but have tried it on some old minis (car not Hope) and it works a treat - no more sticky wheel cylinders etc.

You will need to clean out the old components first as it doesn't mix with normal brake fluid but the results are worth it.
 
got one of these at home will have a look at it tonight
shure you need a syringe to bleed the pro-stop
what lever are you using?
my pro-stop was shite no matter what i did even made up different
length actuators.
mike
 
Jez,

It's been a few years (like 17!) since I had to bleed Prostop and I don't have mine to reference now (maybe I can get a pic from Aaron) but this is what I remember...

The Prostop is a mechanically actuated hydraulic cylinder with one master and one slave side. On the caliper, there should be two threaded ports, one towards the top and one near the side/bottom. Get yourself two syringes (20cc) and a bit of aquarium tubing.

Attach about 4 inches of tubing to the nipple of each syringe and fill one syringe full of your favorite oil (mineral works great, does not break down seals like petroleum based) and the second about half full making sure to express the oil til there is no air in the tubing downstream.

Screw in the mechanical cylinder adjuster about half way...this sets up the master cylinder to be backed off at the end of the process as the bleading / pressurizing will set the pads tight.

Take out the ports, drain the old oil.

Push the tubing into each hole, with the fuller syringe on top.

Compress the upper syringe, filling the cylinder until pressure begins to fill the lower syringe. Slowly work the syringes back and forth, allowing any air bubbles to travel into the upper syringe.

Once your are sure all the bubbles are out and the cylinder is full of oil, gently compress the upper syringe as you retract the tubing so that the oil tops off the hole, replace the port stop.

Flip the fork over and repeat the process for the lower port, removing and replacing the stop.

Unscrew the mechanical piston adjustment so that the wheel travels freely.

Good luck!

rody
 
don't remember it being that complicated ........but then again
my brake was rubbish :) .....so probably doin it wrong....
mike
 
pistons not moving could purely be sticky pistons. fairly common occurance & easy fix. I had 1 sieze on a hope mini & the brake was perfectly bled.
 
sticky hope mini was fixed by a couple of drops of brake fluid onto piston and push back/out a few times. Repeat. May work on this too, but don't get it on your pads :shock:
 
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