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Bleed the brakes again. If that doesn't help, get a one-ton master cylinder.
A prop. valve looks like a biggish chunk with lines in and out of it, NOT a small, squarish thing with wiring. Double check.
When bleeding brakes, start farthest away from the master cylinder and work forward.
Still waiting....
:photo:
OK, OK.... You guys are relentless. <g> Hey, I never game a timeframe this time!
I *do* have the first part of the writeup on my site.
www.bigscaryjeep.com
Click on "M715 Disc Brakes".
It's not really finished, because I have to replace the master cylinder and I'm going to install a proportioning valve. As is (with a bad MC), I have semi-decent brakes good enough to go around the block, so I'm hoping that with a working MC and a prop. valve, I'll be able to lock all 4 without stomping the pedal into the ground. (Remember, I'm using an FSJ vac booster and brake pedal assembly.)
It will be a couple weekends before I will be able to get back to this project but I will let everyone know what happens.
Alright, it's been the stated couple of weeks, so here goes with an update.
UPDATE:
I have a new FSJ (Grand Wagoneer) master cylinder attached to the stock vac booster and pedal assembly. The front and rear circuits are competely separate from each other (no prop valve, yet). The pedal still goes low when brakes finally actuate. They will not lock up. I discussed this with Ray and he recommended a master cylinder with at least a 1 1/4" (1.25") bore.
QUESTIONS:
Has anyone actually INSTALLED and DRIVEN their truck with this conversion? <g> What pedal/master cylinder setup are you using?
COMMENTARY:
I'd like to stay with power brakes. I like them, esp since it's already installed. I like not having to strain my leg or stand on the pedal to hold the brake on a hill.
WAIT, THERE'S MORE!:
I did some browsing through NAPA's site and found a 2005 F350 Super Duty master cylinder with a stated more of 1 3/8" !!! If that's true, I might have to try it, even with a NAPA price of $82.50. None of the specs (on any master cylinder) list the stroke. Is this an industry standard or a deep dark secret???
SHAMLESS THANK-YOU to ELICIT MORE HELP:
Many thanks for everyone help and putting up with this thread that won't die! :D
Hydroboost is the answer to a LOT of braking issues ;)
I got mine from a CUCV donor. But really, most will work fine.
The 1 ton setup should have the right size you want, but I can't remember off the top of my head.
Of course that is hydro and not vacuum assist. Just more stuff to mess with.
So is everyone else using a modified version of the original brake pedal?
After experimenting today with a 1980 Chevy 1 ton MC, I've decided that the FSJ brake booster doesn't have enough stroke to depress the MC completely. And yes, it engages the MC pretty much immediately. I tried "extending" it with a spacer, but then the MC doesn't return to its proper place and it won't release the brakes.
So it looks like I'm back to using the original brake pedal assembly and pushrod.... once I find them in my garage. :( Unless someone can tell me of something else that they are using. I'm kind of bummed that the FSJ pedal/booster assembly won't work since I'm familiar with it, but I guess this means I get to learn something new. :rolleyes:
I am going to have to go through with the installation of Ray's kit also, I appreciate you posting up the trials you're having. I liked the idea of using the Astro van hydroboost, I went to the local pull a part and thiere must have been three rigs with them, I do realize the master cyl. would have to be changed out. I remember seeing a thread on this, thought it a clever idea.
I found the orignal pedal assembly and the pushrod that Jon so nicely sent to me (Thanks again, Jon!). I don't think I'm going to get much more travel out of the stock pedal assembly, either....
I think I'm going to take some time off of this project for a while and frustrate myself with something else and come back to this later.
On my hydroboost setup I had to make the rod longer for it to work correctly. But I wasn't trying to use a FSJ booster (tried and failed is more like it).
Basically, for me, I kept the fsj pedal setup, lengthened the rod, and used the hydroboost and MC from the 1 ton CUCV.
After that, it worked great.
I was poking around www.mpbrakes.com and they make no mention of different stroke lengths. However, they DO make mention of residual pressure valves being required for drums. Ray also told me to make sure there was NO residual pressure valve on the MC I was using. There are NO valves on either port of the Chevy 1 ton MC. Looks like I need to install one of those as well.
Hammer, what didn't work with your FSJ booster? I have a single diaphram booster installed right now, but I also have a dual diaphram boost I can use. However, a hard pedal is not my problem. I have excessive travel. Pedal is near to the floor by the time brakes start working and I have to really stomp on it to get them to stop and/or hold the truck still.