Cutting brake issue (1 Viewer)

[SNLC]

I don't have stock axles. On my rear axle I have duel calipers, one set is for the cutting brakes. I have a CNC cutting brake system mounted between the front seats, levers are pull back to engage the brakes. I have some line locks on them too for my e-brake.

Problem is: they never have worked to well from day one. They kind of act like there is air in the lines but they have been bled so many times I don't remember. Basically I can pull on the lever as hard as possible and not get a caliper to lock up. Braking power even at as hard as I can pull on it is maybe 30-40%.

Calipers are Wilwood, rest of system is all CNC.

What do you think could be the problem? I thought about mounting the levers differently so it is a push not pull set up but I doubt that will fix this problem even if it is a better way to set them up.

 

[CruisinFJ60]

Sounds like they just arent moving enough fluid into the caliper. Why duel calipers? why not plumb into what is already there?

 

[Bret]

Is there a residual valve in line? Maybe taking up too much travel to get the pads against the rotor. Bench bleed the master before install? Are the line locks mounted at the high point of the system? May make it hard to bleed completely. Have you tried pressure bleeding instead of using the pedal?

 

[SNLC]

Sounds like they just arent moving enough fluid into the caliper. Why duel calipers? why not plumb into what is already there?

Yeah I think that is it, not moving enough fluid but I don't know why.

Axles came with duel calipers, one set for regular brakes and one set for cutting brakes.

 

[SNLC]

Is there a residual valve in line? Maybe taking up too much travel to get the pads against the rotor. Bench bleed the master before install? Are the line locks mounted at the high point of the system? May make it hard to bleed completely. Have you tried pressure bleeding instead of using the pedal?

No residuel valve. Plumbed straight from the CNC cutting brake M/C to the calipers via steel/rubber lines. Line locks are mounted as high as possible, right next to the M/C.

Have not bench bled the M/C. I suppose it could be worth a try. Have pressure bled the system more then once. The pads are nice and close to the rotors, not like I need to move them 1/2" to get contact.

I don't know if it will help but here is a couple of pictures pre-plumbing.

 

[Radd Cruisers]

No residuel valve. Plumbed straight from the CNC cutting brake M/C to the calipers via steel/rubber lines. Line locks are mounted as high as possible, right next to the M/C.

Have not bench bled the M/C. I suppose it could be worth a try. Have pressure bled the system more then once. The pads are nice and close to the rotors, not like I need to move them 1/2" to get contact.

I don't know if it will help but here is a couple of pictures pre-plumbing.

Nice tease shot, now you have to show more pics of your link set up and rig

 

[Mace]

How much flex line do you have?

 

[SNLC]

How much flex line do you have?

Just where I need it, a few small sections from where my links mount to the axle/farme.

 

[SNLC]

Nice tease shot, now you have to show more pics of your link set up and rig

there is a whole bunch of me blahing on about it over here....


https://forum.ih8mud.com/chit-chat-section/483379-portal-patrol-other-japanese-4wd.html

 

[leftarmtan]

Do they lock up if you pump the pedal then hold the cutting brake?

 

[Sam Stewart]

Sounds like there isn't enough clamping force to lock the brakes. Any idea how much pressure you have with the set up now? I'm just wondering if it isn't creating enough friction. You could be using all the leverage you have and not actually clamping down on the rotor. Is there any adjustment? Like can you adjust the levers or cylinders at all?

 

[Medusa]

Did you bleed them properly?? Dustin Webster's method seems to work the best and has solved problems similar to yours for many individuals. See the RedBullJeep posts in this thread (especially post #13):

Bleeding a system with cutting brakes - Pirate4x4.Com

Also note that "playing" with CNC brakes before they have fluid in them can often ruin them.

 

[SNLC]

I don't see any adjustment on the system. They were not played with when dry....


Again I have duel calipers on my rear axle. One set of calipers is for the cutting brake system. That is seperate and not parts of my normal brakes. So pumping the pedal will do nothing.

Thanks for the link, looks like some good info in there!

 

[Tapage]

you get 'em as a " kit " cutting brakes with calipers ?

 

[SNLC]

you get 'em as a " kit " cutting brakes with calipers ?

Nah bro....calipers came with the axles and we bought the CNC unit seprate. When I ordered the axles I told them I wanted to run cutting brakes so that is why they came with duel calipers. I am sure it will work great if I can get the calipers clamping hard enough.

 

[CruisinFJ60]

How about you just give me your axles and I will trade you for my FF 14B with disk and finish my D60 for you. sounds like a good deal to me...

 

[77TPIFJ]

as stated above they are probably not getting enough fluid. are these cutting brakes hooked up to the brake sys. as they are supposed to, or do you have the cutting brakes hooked up directly to your second set of calipers? maybe show us how they are plumbed. nice patrol

 

[77TPIFJ]

No residuel valve. Plumbed straight from the CNC cutting brake M/C to the calipers via steel/rubber lines. Line locks are mounted as high as possible, right next to the M/C.

this makes me think you do not have them hooked up to the vehicles brake system. you might wanna try to hook up a reservoir for your cutting brakes.(also may want to call cnc and check the specs on them to see if they would be able to move enough fluid for what you are doing with them) or run 2 of these if you want to run the second set of calipers separate from the vehicle's existing brake system.

hope this helps

 

[Mace]

4 piston wilwoods? If bet that you just do not have nearly enough fluid being moved to get any clamping force. Residual valve might help. But the big 4piston willwoods take a lot of fluid to.work..

 

[SNLC]

Ok I will take a few pictures soon. Maybe I am misunderstanding what you mean by residual valve...?? I have a resivoir, it is built into the CNC unit.

I am running a hybrid master cylinder in my brakes, kind of anyways. It is a Y60 Patrol MC bolted to a 160 Patrol master vac. It is around a 1" bore, maybe a touch larger, ie 1.25". Been awhile I don't recall exactly off the top of my head. However, this stops the truck great with no problems.