Still Trying To Improve Brakes

Sounds like at least a possibility that by pumping after closing the m/c, you may have run it dry and pushed more air into the system.

 

You are right on. I went through the same changes and I used the advice of experts to have a well balanced system. Wilwood knows there ****.

 

Okay. Boy this is frustrating! First, to clarify. Yesterday, after we bled the system, I closed the master cylinder and my wife pressed the brake pedal. It took about 5 strokes to get the pistons of the calipers to reach the disc. Thus the spongy pedal.

Tonight: We bled the system again. Rear and Front. Pedal is still spongy. I’m not sure, but I have two hypotheses. First, the master cylinder is bad. It is a brand new unit from Horsepower sales, but I’ve been stomping on quite a bit the last few weeks. Second, I think I have free play way too large. In other words, the push rod may be too far from the piston and doesn’t engage early enough. I think this is causing two problems. One, it’s not allowing me to sufficiently bleed the system because the stroke is too short. Two, the short stroke isn’t allowing the system to build sufficient pressure. I will adjust the push rod tomorrow and make it longer.

 

Thanks. I am about 3/4 to 1 inch away from the piston. Will be adjusting it first thing tomorrow.

 

Congratulations you've just won a test drive.

Will you be at rush springs or Fulton this year? Maybe I can put the spring reunion on the calendar.

 

That's a problem I had with my master cylinder swap. You should have 1" max travel at the pedal arm / floor. At the pushrod this would be about 1/4". You don't want it to be against the master cylinder because it can hold pressure in the system if it is too tight.

 

I bled the brakes again, moved the pushrod closer to the piston and tested. The brakes still do not stop hard even when standing on the pedal! I did a number of stops in the neighborhood and noticed the pedal was moving further down (longer travel). I looked underneath and noticed fluid at the back of the master cylinder. I was careful to clean it after the bleeding. It is leaking. I wonder if this is why I never could stop good? Sorry the image is dark. It was getting late.

 

I see the fluid. That's your problem

 

Not copper. It’s a popular line that is easily bent. Can’t recall the name. Get excellent reviews. I can only guess it’s coming out of the rear of the master cylinder where the plunger is.

Funny, when I bench bled this unit, fluid dribbled out of one of the ports. I’ve never observed this before. Usually after bench bleeding the ports are closed and won’t leak. I was concerned and called Horsepower sales and the guy said is was normal. I guess I got a bad master cylinder from the start. It seems to happen quite frequently to me—in other words, getting hosed on buying new parts. Am I the only one?

 

The big issue I see with this situation is buying the master cylinder from vendor A and the caliper system from vendor B. When you do this you have a revolving door for the buck to pass.

Externally the brake system should be sealed.

I used a factory cj bracket and it did need notched for the brake pedal due to a change in the pedal arm when they went to the dual system master cylinder.

Here is how mine looks now:
20221213_130310 by Joe the adapter guy, on Flickr

 

Fwiw I had a wilwood residual pressure valve fail.
You can see the split duckbill on the right. I did the dual reservoir swap Dec 2022, button head spindle bolts and disks April 2019. So two and a half years on the residual pressure valve.
20221214_140308 by Joe the adapter guy, on Flickr

 

I paid $400 with shipping for the dual master cylinder, bracket, and prop valve in May 24 and it failed almost immediately. At least you got a few years out of your parts.