Bleeding brakes with CNC triple reservoir and Wilwood pedal box - HELP

[Rotorcraft]

So I was reviewing the instructions that came with the CNC triple reservoir setup, and it says this:

"if you are bleeding a Dual Cylinder Brake Pedal Assembly, you will need to open a bleeder screw on the front brakes and the rear brakes at the same time"

The instructions for the CNC triple reservoir also state in bold letters, PRESSSURE BLEEDING IS STRONGLY RECOMMENDED

I would love to hear exactly how others have bled their system when using the CNC triple reservoir along with the complete kit Wilwood pedal box (two master cylinders with balance bar)

I nice step by step from someone would be very much appreciated!

Thanks!!
Jeff

[edwardb]

I can't give you a complete answer because I haven't used the two master cylinders with balance bar set-up on either of my builds. But I have used the CNC reservoirs for both. The comment about pressure bleeding is (I think) referring to using the CNC 1459A pressure cap for bleeding. Works really well and I highly recommend. I assume you have one reservoir into the front circuit MC, and one into the rear circuit MC. In general, the sequence is as follows:

1. Bench bleed the master cylinders. Usually this is done by disconnecting the brake line output and temporarily replacing with a short length of tubing back into the open top of the reservoir. With fluid in the reservoir, pump the brakes until you have a solid flow of fluid back into the reservoir from the temporary line. This means you have replaced all the air in the MC with fluid. Replace the brake line.

2. Put the pressure cap on the rear circuit reservoir. Through the Schrader valve in the pressure cap, put in several pounds of pressure. I turn my compressor regulator way down and use that source. But be careful. You could also use something like a manual bike tire pump.

3. With a short hose and bottle on the rear PS bleeder, crack open the bleeder. Continue until solid fluid flow and no bubbles. Don't pump the brakes. In fact this will mess up the sequence. Watch the level of fluid in the reservoir. If you let it all out you get to start over. Also you may need to add air pressure to keep the flow going, especially for a new system. When satisfied all the air is out, close the bleeder and remove the hose and bottle.

4. Then go to the rear DS bleeder. Same process.

5. Switch the pressure cap to the front reservoir. Then follow the same process for the front PS, then front DS.

This is the process I've followed for both my builds and worked very well, except for the one situation I had on my Mk4 where the Hydroboost pushrod was the wrong length. Once fixed, bled normally.

Others can chime in on how this needs to be modified (if it does) for the Wilwood double MC configuration. Note also this same process can be used for a hydraulic clutch, i.e. the third reservoir in your CNC triple reservoir assembly.

[Rotorcraft]

I can't give you a complete answer because I haven't used the two master cylinders with balance bar set-up on either of my builds. But I have used the CNC reservoirs for both. The comment about pressure bleeding is (I think) referring to using the CNC 1459A pressure cap for bleeding. Works really well and I highly recommend. I assume you have one reservoir into the front circuit MC, and one into the rear circuit MC. In general, the sequence is as follows:

1. Bench bleed the master cylinders. Usually this is done by disconnecting the brake line output and temporarily replacing with a short length of tubing back into the open top of the reservoir. With fluid in the reservoir, pump the brakes until you have a solid flow of fluid back into the reservoir from the temporary line. This means you have replaced all the air in the MC with fluid. Replace the brake line.

2. Put the pressure cap on the rear circuit reservoir. Through the Schrader valve in the pressure cap, put in several pounds of pressure. I turn my compressor regulator way down and use that source. But be careful. You could also use something like a manual bike tire pump.

3. With a short hose and bottle on the rear PS bleeder, crack open the bleeder. Continue until solid fluid flow and no bubbles. Don't pump the brakes. In fact this will mess up the sequence. Watch the level of fluid in the reservoir. If you let it all out you get to start over. Also you may need to add air pressure to keep the flow going, especially for a new system. When satisfied all the air is out, close the bleeder and remove the hose and bottle.

4. Then go to the rear DS bleeder. Same process.

5. Switch the pressure cap to the front reservoir. Then follow the same process for the front PS, then front DS.

This is the process I've followed for both my builds and worked very well, except for the one situation I had on my Mk4 where the Hydroboost pushrod was the wrong length. Once fixed, bled normally.

Others can chime in on how this needs to be modified (if it does) for the Wilwood double MC configuration. Note also this same process can be used for a hydraulic clutch, i.e. the third reservoir in your CNC triple reservoir assembly.


Thanks! - I also called CNC (before seeing your email) and they confirmed the same process. thanks again!

[VdubJoe]

I do it the old slow way. Let gravity work. Hose on fitting' crack and keep an eye on the reservoir. Done it for years.
If im in a rush i get someone to pump the pedal.

Joe

[CraigS]

I also let gravity do most of the work but usually finish up w/ my wife pumping the pedal. I open one front and one rear rather than all 4. Works fine and I only needed to make up two bleeder bottles.

[Rotorcraft]

Thanks guys!