I bought the shoes from KW, but set them aside. I didn't like the fitment, so I went to the original shoes, with some fresh brake material riveted on. The material is most likely asbestos, because there was no telling how long it had been sitting on the shelf.
There are boot springs on the original wheel cylinders, but I didn't tear into the replacements to see. Even with the cup expander, with the reservoir being so low, the fluid still has a tendency to go back and equalize back at the master. With all this being said, when I get back to it I am going to order a new master and wheel cylinders to start fresh.
I wonder where I can get some shoes with thicker linings. I bet the rivited ones you found were thicker.
It is puzzling what is going on with your brakes. Since you have a firm pedal it has to be a volume of fluid vs motion issue. If the volume of fluid isn't sufficient to move the pistons out to contact, you would have to pump it again to get the next movement. Like a jack, each pump moving it a little further. With that thought, I pressure bled my system. That would push the pistons out and insure maximum fill. After that I did go around manually but, the pedal is real good for what it is. I wounder if one or more of your cylinders are sticking in when you bleed it and consequently, affecting the total volume of fluid? I like your "square one" approach. There could be a gremlin in there.
With nothing preventing the fluid from returning to the reservoir after the pedal releases, it takes the path of least resistance. If the master was mounted to the firewall, and the fluid has to go up hill, it stays in the line as is ready for the next brake application.
The brake lining material was from when I worked at a Ford tractor dealer. We dealt a lot with the N series of tractors, and could rebuild all aspects of every component. I trimmed them down to fit on the length then peened in new rivets. The holes for the rivets didn't match up, so I filled the holes in the bracket and re-drilled. Sounds like a lot of work for not much gain, but I just didn't like the way the reproductions fit.
gm, do you have the Service Manual for Universal Jeep Vehicles? I was looking at section P. In paragraph P-2 they talk about the check valve and the return spring, and it says both are used together. On page 225 they show two exploded drawings of the master cylinder. It does show a check valve FIG. 279, and FIG. 278. Also shown are the wheel cylinders with springs in FIG. 280 and 281. It is confusing to say the least but it looks like it takes both a spring in the wheel cylinder and a check valve. The valve is actually a seal and spring on the end of the piston. It isn't a conventional "valve". Nothing is in the line port.
The valve is not conventional to say the least, it doesn't really do much to retain line pressure, but is more to equalize the residual pressure by restricting the flow. The holes in mine may be too big, or there is too much slop in the bore of the cylinder. I believe I'll start with a master cylinder and see what happens from there.
The set up certainly explains how a little dirt in the system or wear, and it's not going to work very well. If this is it, it will be interesting. The springs are in your wheel cylinders. If the master and/or check valve is at fault, the spring in the wheel cylinder is not enough to stop the "double stroke".
The Mechanic’s Manual for the 1948 vehicles has a passing explanation of the check valve and its function:
“The holes in the piston head are for the purpose of allowing the fluid to flow from the space in back of the piston into the space between the primary cup and the check valve, keeping sufficient fluid in the lines at all times. The holes in the check valve case allow the fluid to flow through the case, around the lips of the rubber valve cup and out into the lines during brake application. When the brakes are released, the valve is forced off the seat permitting the fluid to return to the master cylinder.”
What they don’t say specifically is that as the fluid returns to the master cylinder, pressure in the brake lines drops and at some point the spring in the check valve overcomes the pressure in the lines and then it seals off the lines to keep the pressure in them from dropping to zero.
I guess I did know that there was something you dropped into the master cylinder when you did a rebuild, but I didn’t know it was a check valve.
The four wheeler was a close encounter with a hardwood. The tire shelf was a necessity, especially with the 37" takeoffs that are waaay too big for any of my junk to mount to, but the price was right. Plus now all my Heep wheels and the South's largest selection of BF Goodrich Silvertown and Firestone formerly studded snow tires from the '50s are shelved up and off the ground. Next my yard guard Shepherd had a knock down drag out with a snake, in which her left ear may never quite stand up like it did before, plus a part of her lower lip had to be removed and stitched back together. Now I have a '99 Mustang clogging up my garage for my brother in law. It just needs an idle air sensor that he can't afford, that when running the engine looks like it wants to turn oil pan up in the engine bay. 10 minutes worth of work, and it would be on its way back home.
What kind of snake attacks an ear and a lip? I'm against that. I had a dog once that got bit by another dog and a day later his ear swole up and stood straight up for the first time ever. Love the garage pic. Being a retired tire hoarder, I love that idea to lift em up. Mine were outside and froze and thawed, houses for critters and such. When we moved off the place I lucked into a annual free dump day across the hills where they let me unload a u-haul full of tires no fee. That was nice, but I still miss my favorite and yours, those ones with holes for the studds. Side note. I also had a convertible with four studded tires I used to run down six miles of windy hilly dirt mountain roads. Front wheel drive. Except for the time that cow jumped up from asleep in the ditch and mooed at me in my side ear loud enough to scare me half to death and cause a swerve, a few deer and elk scares, that was some commute. Cool garage. So what's up with the Jeep? Any progress? C'mon man.
Reply With Quote
