Bobby,

Yeah, I drove the donor car in my driveway but not down the highway since it was not registered. The brakes seemed perfect then. Of course, that was two years ago now. I put the Mity-vac on all four corners when I was bleeding the system and I was getting fluid then. I wonder if somehow the calipers have seized or something like that while sitting. Maybe tomorrow I should check that out. I wish I had somebody to push the pedal down while I tried turning the front wheels. A helper comes in handy from time to time.

 

Great news Vern. Feels good I know. Around the block is next. Joe

 

This systems uses a combination valve. I know the lines are correct and the system is clean since I blew everything out with compressed air and installed all new brake lines. Can a combination valve go bad just sitting? Wonder how I would determine that? I have given some thought to yanking the combination valve just to see what happens but I hate to do that since it's a lot of trouble to re-plumb everything...

 

...not unless I drag my feet to stop! Thanks.

 

Vern,
I know what you mean. Find yourself a stick or something to wedge between the pedal and the seat.
If you were getting fluid out of it while vacuum bleeding then that pretty much eliminates a blocked line.

I don't know if they can go bad from sitting but I think they can get out of whack if the system was completey empty and refilled. I think that these valves basically consist of a housing and a spool type valve. If that valve gets pused all the way to one side(front or rear) due to no pressure being on the other side during bleeding, then when the other side (front or rear) is bled the valve is stuck over to one side or the other and the equalized pressure will not let it center.

Don't quote me on this stuff. It seems like I read something about it somewhere. I think there is a procedure to correct it though.

Bobby

 

Bobby,

You lost me on that. This one was definitely emptied and refilled. I'll snoop around and see if I can find out some more about the centering stuff. I have no idea how these things work internally...

 

Heres a link describing the operation of a valve;
http://www.cougarclub.org/atsotc/brake_valves.shtml
http://www.guzzitech.com/BrakePropor-Stan_M.html

 

Wow! I never knew the inner workings of these things were so intricate.

 

Cool huh? hope it something simple like the spool valve being slightly out of place or something like that. Maybe it allows a flow of fluid but not enough pressure.

As with any problem, step back, crack open a frosty beverage and think to yourself "...if I ever get my hands on the little rascal Murphy, I'll beat the tar out of him"

Bobby

 

Vern,
Here's another troubleshooting guide on the Classic Performance Parts website. Scroll down to the "test combination/proportioning valve" and give it a try.
http://www.classicperform.com/TechBo...t.htm#testprop
Good Luck!

 

Congratulations! Looking forward to more pics in the Gallery!

 

Bobby,

I tried your suggestion and wedged a piece of wood between the seat and the brake pedal. If I pump up the brakes with the engine off and wedge the brake pedal down I can still turn the front wheels with the truck jacked up. If I pump them up and start the engine and wedge the pedal down I cannot turn the front wheels. So, that means the front brakes are engaging when the booster is engaged...just not engaging enough to stop the truck. I took another short trip down the driveway again and they definitly start to grab better if I keep pumping them but as soon as I quit it's back to nothing again. Do any of you brake experts out there know what all of this adds up to? I might drag out my Mity-vac again and try bleeding one more time. I do not want to get into dissassembly of that combination valve unless I have to...

 

Vern,

From the sounds of it everything is working, you just are not getting enough pressure to the fronts. I'm wondering if the spool valve in the combo valve is slightly off center.
It seems like one of the links that was posted has a way of recentering the valve without havin to take it all apart (I don't remember which link it was though, one of the 3) I think it came down to releasing some of the pressure from the opposite side, in this case the rears. I just skimmed the article yesterday and I've slept since then so I don't remember (dang, I can't even blame it on frosties)

I know you are working by yourself, I wonder what would happen if you wedged the brake pedal with the wood and then went out and cracked the line to the rear brakes at the combo valve. In theory this would create a lesser pressure in the rear part of the system than what is in the front which should push the spool valve in the combo valve towards its center position. (heck, it sounds good on paper)

Bobby

 

Shoot fire, I drive my truck almost every day. Oh, wait, you mean your project, as Emily Littela would say "Never mind".

 

Congrats on driving your truck. Man, I forgot what it felt like. 52 Panel is progressing in fits and jerks. Hope to be back on the road in time for the Turkey Run in Dayton Thanksgiving weekend. Post some pictures of your project.