evernon's Baja Build

[evernon]

Single handle cnc. Its been a few years since I bled this setup and I think I had my son at the rear calipers as I pushed on the pedal and pulled or pushed on the handle. All break lines including the flexible lines were new when installed. The pedal and handle don't feel spongy like it needs to be bled.

[Ol'fogasaurus]

That style does have the one limitation (locking the diff) that the double handles styles have but mostly I am concerned about the soft lines as they, when they get old, can swell and limit the amount of fluid, and swiftness being moved back and forth.

As far as bleeding goes this is how I was told to do it at different times by a couple of VW off-road mechanics; it is like what you described with the one difference.

Bleed the one side of the brake system the normal way but when it is OK you then throw in the turning brake handle into the bleed. When the one side of the brake system is done then, with the brake pedal held to the floor, you push/pull the brake handle for that side to its full end position. If no bubbles come out then close the bleed valve you should be done with that side. If bubbles do come out continued on with the bleeding of the handle for that side.

When everything is OK then you let up on the foot brake pedal but keeping the turning brake handle in the full applied position. Then, using the foot brake, pump the foot brake and the handle will be pushed (forced), in stages, to it's full open position. Keep the reservoir full at all times also . Then repeat the process for the other side.

Not everyone does it this way and have good luck so this method is more like a double check/back up way of doing it.

Lee

[evernon]

After reading up on this, I have decided to add a new pair of 4 piston calipers an will leave the old ones in place to function as the parking brake. After moving the caliper around, I am thinking the top is the best option for the new caliper. The front would be better because bleeding is easier with the calipers mounted in a vertical position. Unfortunately the angle of the boxed arm complicates things though it might be possible. The top surface is would be much easier to fab mounts on but to bleed these calipers, they would need to be disconnected to elevate the bleeders, plumbed with a flexible line to enable this. Any thoughts?

[Ol'fogasaurus]

I just looked it up and while it used to be DOT illegal for hydraulic parking brakes things seemed to have changed somewhat but you have to meet certain https://www.law.cornell.edu/cfr/text/49/393.41 specs.

Lee

[evernon]

Haha, in Montana anything is legal. Funny the cable operated parking brake provides more stopping force than the pedal! Other options would be a line lock, or willwood makes a cable caliper. I would probably shed a few pounds with either of these options

[Ol'fogasaurus]

Sometimes... what is legal, what is illegal and what is right are all different things. For example, if you live in pretty flat areas the e-brake isn't as important (yes it is but..) as when you live in hilly or mountain areas. Play for safety, yours and others, and you will be happier in the long run.

Lee

[Skidmark]

My interpretation was the parking brake system was required to be separate from the main brake hydraulic system. If the parking brake system is separate, but hydraulic as well, it meets MY interpretation anyway...

[Ol'fogasaurus]

My interpretation was the parking brake system was required to be separate from the main brake hydraulic system. If the parking brake system is separate, but hydraulic as well, it meets MY interpretation anyway...

You might be right Skid but when I got into it years ago that was not true. Over the years a lot of things (as I alluded to) were tried and shut down. If big business got things changed what can I say. The e-brake on a different system is an upgrade but it too can fail but then so can a cable .

Anyway, all the states seem to be different on a lot of rules hence the DOT rules for the US so that is what I guess we here in the states should go with.

The discussion was not meant as being mean... I just thought it needed to be discussed.

Lee

[evernon]

Got the willwood callipers. The plan is ro remove the break line from the old calipers and either re bend it to fit the new topside location or purchase a new rigid line to run from the flexible connection to the caliper. I believe that the connection fittings i have now are m10 straight and the willwoods need a 1/8 27 npt. If I rebend the lines, I will need to get adapters for the calipers. The calipers are also closer in to the rotor meaning that I will need to use thinner mounting tabs to get them to fit. I am even thinking of positioningthe mounts with a thick shim between the caliper and mount, allowing me to install the mounts a little further inboard, flush with the end of the arm. The mounts will be really short as the caliper only needs to be elevated about a millimeter off the top surface of the arm to be in position

[evernon]

So I am having an issue bleeding the brakes. I believe that I have all the air out of the lines from the cutting break to the new rear calipers. The calipers are visually clamping and the resistance on the handle feels right. The pedal however has almost no resistance and will go straight to the floor. If I first activate either rear break with the cutting brake, the foot pedal will feel firm and will continue to hold if I release the hand brake. If I release both, the foot pedal will go straight to the floor the next try. Anyone have an Idea what's going on? The MC was working fine before this project. It also didn't seem like the MC was pushing very much fluid during the bleeding process.
Thanks!

[Ol'fogasaurus]

So I am having an issue bleeding the brakes. I believe that I have all the air out of the lines from the cutting break to the new rear calipers. The calipers are visually clamping and the resistance on the handle feels right. The pedal however has almost no resistance and will go straight to the floor. If I first activate either rear break with the cutting brake, the foot pedal will feel firm and will continue to hold if I release the hand brake. If I release both, the foot pedal will go straight to the floor the next try. Anyone have an Idea what's going on? The MC was working fine before this project. It also didn't seem like the MC was pushing very much fluid during the bleeding process.
Thanks!

Try this: when bleeding the system with turning brakes especially if the turning/cutting brake handles are on the top of the tunnel (or mounted higher than the foot brake pedal) you start with bleeding the foot brakes (you can't do the gravity bleed with this setup). Then with your brake foot pedal held on the floor using your foot after bleeding the foot brake on passenger side (the longest distance from the pedal assy... this is the normal way of doing it and it covers both right hand and left hand drive) then you can start the bleeding of the turning/cutting brake.

Pull the handle to see if it is soft or not from the foot re-bleed. If it is soft then close the bleed valve keeping your foot brake pedal to the floor then pull the turning/cutting brake handle at the end of the pull then have someone else close the bleed valve then release the pressure letting both go back to a normal position. Then, keep pull pressure on the turning/cutting brake handle at full pull then using your foot pedal then pump the brake which causes the turning/cutting brake handle to return to it's forward position. Check the foot brake and the turning/cutting brake handles to see if they are hard and working the brake shoe correctly. If OK then duplicate the other brake the same way. If not try the turning/cutting brake bleed again. Also, keep track of the brake fluid in the reservoir to make sure you are not bleeding it dry then having to start over .

I am not sure if "pressure bleeding" the system with work this way but if you have the stuff for it it is worth a try.

I hope all this makes sense! If not let me know and I will try to re-write it to make sense.

Lee

[Leatherneck]

Even if MC “was” operating correct I would start at square one and bench bleed it, then move on to next part, checking connections as you go.

[Ol'fogasaurus]

Even if MC “was” operating correct I would start at square one and bench bleed it, then move on to next part, checking connections as you go.

Bench bleeding is a proper thing to do. It is the rise in the connection tube to the turning brakes then back down to the wheel cylinders where the problem is. That is why you bleed the brakes then, holding the pedal for the side you are bleeding (the shoe farthest away from the MC), you work on the turning brake handle. When there is no bubbles or anything from the turning brake handles you continue to hold the turning brake handle to full pull then let up on the pedal then pump it and it will pump the handle with you pulling on it still back to its stop. Once done repeat for the other side.

If there is no rise to the turning brakes it still is a good idea to bleed it this way. Again, I don't recommend soft lines (they would be ersatz) in the system until the rear to cover the rear suspension rise and drop.

On the e-brake on the top... as long as the slave is horizontal is it probably OK but not sure if the slave is vertical. This is something that came up so long ago most of you weren't old enough to fart.

Lee

[evernon]

Have a 2lb residual valve ordered. Apparently this can solve the soft pedal issue. If I had air trapped somewhere, wouldn't the pedal get firmer if pumped? Basically it's the same configuration as before and I didn't have any issues with bleeding after the original build. I am hoping that it is related to the increased volume of fluid needed for the 4 piston calipers.

[Ol'fogasaurus]

... If I had air trapped somewhere, wouldn't the pedal get firmer if pumped? Basically it's the same configuration as before and I didn't have any issues with bleeding after the original build.

If there is air trapped in the brake system it would be softer/more compressible than a full load of brake fluid as liquids are harder/stiffer to be compressed like air can.

"A "residual pressure valve" is used when a master cylinder is mounted equal to or below the horizontal plane of the calipers or drum brake wheel cylinders. This valve prevents fluid flow-back." (I forgot to post the source of this but do a search and it will come up) The "below" term is more of a "slightly below" term than when the turning brake cylinder(s) is mounted on the tunnel for example.

Lee