Disc brakes on Dana 25 with stock single chamber MC

Actually disc brakes normally have larger lines due to the larger amount of fluid required to push the larger pistons in the calipers. Sometimes if the wheel cylinders total surface area (2 pistons per wheel x 2 wheels) equals the total surface area or is close to the same surface area of the caliper pistons (generally 1 piston per wheel x 2 wheels) then the lines may be the same size..

The pressure is built by cylinder and piston diameter not by line size. This is where Pascal's law comes into play.

If the line diameter is too small then the restriction can cause too little fluid flow which will result in a delay in brake application. If too large, won't really have an effect on fluid flow other than in extreme situations causing a low pedal. It would have to be a very extreme too large diameter mismatch to cause a real problem though.

 

when plumbing the residual pressure valves into the brake system, where should they ideally be placed? Close to the master cylinder? Close to where the lines T off and go to each wheel? Does it really even matter or not?

 

Well just to update, I had pulled the master cylinder apart and removed the check valve altogether. I cleaned it up and put it back together (it was newer and all the rubber parts were like new) with a new Y fitting on the output and a new brake light switch with new copper crush washers and put it all back in.


(That's POR-15 engine enamel in aluminum on the motor, MC, and gearbox)

I purchased a ton of pre-made 3/16" brake lines after carefully planning out where I was going to place them all, and then using a tubing bender and a lot of patience, I made and installed all new brake lines. At the Y fitting, I have one line going to the front brakes, and the other going to the rear brakes. I have the RPV placed close to the MC as per the instructions.



After all that and spending a lot of time bleeding fluid through the system, it's been doing great. The front disc brakes don't drag anymore, and the pedal still feels great.

I also found something else out about the Wilwood RPV units. You need to buy an adapter fitting that screws into both ends in order to mount standard 3/16" brake lines to it. These adapters cost about $5 per at Summit, but I was at a local hydraulics shop and bought 4 of them for about $1.

 

What tires / size are you running, they look sweet!

 

Can someone post exactly how to remove the check/residual valve from a stock single res. master cylinder?

Thanks!

Troy

 

Sorry to go digging, but those are 33" Buckshot Mudders, about 6 or 7" wide and bias 6 ply I believe. The original Buckshot Mudders that made themselves known in the southeast, not the Maxxis garbage. They're still manufactured by Gateway tire. If you get in contact with Denman tire they can hook you up with a distributor.