Brakebooster not working or?

[The70RT]

YUP sounds like air, or you have installed the residual valve backwards. (?)  (Your bleeders are coming out the top in the back right?)   

Don't kick on a man already laying Neal. Actually the residual valve was mounted backwards due to wrong brakelines so it's now just a pass thru.

I will check for air in the "curly" area. Any idea why the oil is forced back up into the reservoar
when I'm turning the wheels?

Something else, how tight do you adjust the rear brakeshoes? They have to be adjusted with drum on I suppose, otherwise the drum wouldn't go on.

Per

You can adjust the rear with them off because if you try to put the drum on and you can't, then your too tight. Adjust them for they just barley touch. You may have to adjust a bit after they seat in.

[elacruze]

I adjust brake shoes with wheels on and lugs tight, because it may distort the drum a tiny bit. Rotate the wheel, tighten the adjuster until you hear the shoe begin to touch the drum. Push the pedal to set the shoes, then readjust just until you can tell the shoes are beginning to drag the wheel-enough to just feel the difference when you rotate the tire by hand. This small amount of contact will polish off after only a few miles, without excessive heat.

The fluid returning to the master cylinder is normal, just the volume in the hoses changing slightly as they compress. This should be a very small amount, though, unless something else is going on like your calipers are being pushed back some while turning the wheels.

[b5blue]

I agree!

[The70RT]

I agree as well but it is easier for me to adjust the star adjuster with the drum off and back on a couple times. If you have new drums they come off and back on easily to get the same slight rub effect.

[Belgium R/T -68]

Couldn't a test be to adjust the shoes untill they are tight to the drums because if the pedal then still goes deep it must be air.

Something else, when driving backwards the brakes almost doesn't take at all.

Per

[b5blue]

You can snug them well but undoing can be a challenge! It should stop well in both directions, I wish I could help you Per! 

[Belgium R/T -68]

You can snug them well but undoing can be a challenge! It should stop well in both directions, I wish I could help you Per! 

I will send you a planeticket Neal, then you can see our new lemonbeaglepuppy.

Per

[Belgium R/T -68]

My residual valve or the "hold off valve", the brass valve located on the front to rear brakeline under
the front seat is empty. My brake lines front to rear had the wrong fittings and since in and out has 2
different sizes I removed the valve inside untill I have new brakelines or fittings so I could drive otherwise NO oil is getting to the rears.

Now something hit me, can it be that the now empty brassblock act as an airpocket and that's the reason I can't get the air out?

Untill I get new lines/fittings I could remove the brassblock and use a piece of hose instead to test if there will be any difference?

Per

[b5blue]

A: When can I leave! B: Can I have the pup!    We are on to the problem! Post pic. of what you have, my understanding is this, the distribution block for your set-up now should just be for splitting front brake line from master to left and right. The rear line needs a "proportioning valve" that is adjustable to restrict (reduce) line pressure to the drum brakes, that compensates for the difference between disk (That uses a much higher volume of brake fluid) and drum. (That have much smaller volume fluid needed.) The brass parts/blocks below your master cylinder did 2 or 3 things from the factory when new, 1: All had a "unbalance" detector (Tiny rod that if pushed forward or rearward from a large difference between front and rear brake pressure) that did 2 things, A: Acts as a switch since if it moves it (being held in place by tiny O rings thus insulated from being "grounded electrically") grounds out to the brass block and triggers the "Brake" light on the dash. B: (If I'm not mistaken) Acts as a limiter to restrict flow to the low (malfunctioning) side to give maximum fluid to the side (front or rear) that is working. BE CERTAIN IT IS CENTERED! (If all your electrical is 100% working and the wire is hooked up that, the dash brake light should be on if it is not centered) 2: Splits output from master cylinder for left and right front brakes no matter if disk or drum. (Rears are split for left and right at Tee Block on axle) 3: If the car had disk brakes there would be the "proportioning valve" feature located there. That feature (the factory "proportioning valve) is/was a very generalized part, the same one used for all cars, not "tuned" for each cars specific needs and best working ratio for engine weight, size brakes and such. The residual pressure function (Located inside the factory master cylinder) was intended for the old way they made drum brake slave cylinders, it held some pressure to the slave cylinders rubber seal to hold it tightly in place, preventing it from seeping brake fluid when under no pressure at all. (fully relaxed) It is my understanding that for many years now they have added a thin steel disk to that seal and the residual pressure valve is not needed, it could still be useful by retaining some pressure to effect a kind of "pre-load" in there to reduce reaction feel but if the slave cylinders have been replaced in the last 15-20 years not required. My car, a 10 inch drum (front and back) has just been converted to manual brakes. (Due to booster failure and a lack of money or desire to deal with booster issues like you and others have experienced) I like the results far more than expected, not having that "Z-bar" set-up altering peddle ratio (I drove the car for a month with no booster function     but with that entire assembly all still in there, booster vacuum plugged off) the difference is huge! The Z-bar assembly cripples peddle pressure and without boost took much force to slow the car even for me. (I'm not weak after 30 years working construction every day!) Well there is a review of what I know to tell you, I'm certain some if not all you knew but 2 heads are better than one. Please read the Mopar Action "Disk-O-Tech" online archive as right now you have all of the components they recommend using and it is the source of much of what I have mentioned. (Along with my own findings) You can use this as a guide to alter what you have to get it to function and adjust then you will know how to order replacement lines specified to your exact placement of modifications for a finished system.         

[Belgium R/T -68]

OK, here's what I have now and was sitting on the car from the beginning although these are new
aftermarket. As said, car is factory discbrake. The first pic shows the hold off valve that is now
turned 180° and emptied of the valveparts. There was my idea about that piece now creating airpockets. Second is the block that distributes from mastercylinder.

[Belgium R/T -68]

Here are some options. I have this valve that you can regulate the pressure from front to rear,
maybe that one instead of the hold off valve? Need some extra fittings though because you can't put the brakelinefittings directly into that valve.
Secondly, the distributionblock on pic 2 came with the discbrakekit but since I use stock mastercylinder I didn't think it would brig anything to use that one, don't like the looks of it.
What's best thing to do? Anybody with same factory set up have the same parts?

Per

[b5blue]

YES and Yes!

[Belgium R/T -68]

YES and Yes!

You mean use the valve with manual regulation?

I bought it 10 years ago but never used it so I guess it should be alright?

Per

[b5blue]

Correct, that is the right part to install. I have a "new" old school Mopar racing one it's big, heavy, and ugly and I will be using it for the same thing. Remember if you sort all this out with adapters you can specify the location and size of fittings on the new lines you get and then it will look nice. I do believe your booster is working, you did say it sucked down the peddle when you started the engine. (That's a good sign)    

[elacruze]

I think I missed something...

You have no holdoff valve? If not, the rear brake shoe springs will push the cylinder pistons all the way back and you'll get half a pedal or worse, maybe two or three pumps to get it to firm up. If there's any air in the system it's even worse.

[Belgium R/T -68]

I think I missed something...

You have no holdoff valve? If not, the rear brake shoe springs will push the cylinder pistons all the way back and you'll get half a pedal or worse, maybe two or three pumps to get it to firm up. If there's any air in the system it's even worse.

No, had to remove the valve inside the brassblock because in and out were mixed so I couldn't fit the brakelines correct. So, fix the holdoff valve
and/or mount the MP valve with regulator?

With drums off and pumping the brakepedal, the shoes doesn't moves.

Per

[elacruze]

I'm wondering if your master cylinder is missing some parts!

Try plugging the line ports off directly on the master cylinder, see if you get a tight pedal. Work your way downstream, opening one line at a time until you find the culprit. This is messy and requires the correct caps and plugs, but the scientific bulldozer will not be stopped.

[Belgium R/T -68]

OK, will do it again. Did it before I found out that the hold off valve was wrongly mounted and stopped the oil from going to the rear.

What about that valve now, is it necessary to have one? Does the adjustable one have the same function?

Per

[maxwellwedge]

Try properly bleeding the M/cylinder as well. An improperly bled master will cause those symptoms as well.

[b5blue]

I'm not following what elacruze is saying about a hold off?    The shoes rest against the large stud on the top of the backing plate and adjust on the bottom end, (with the adjuster) this all has nothing to do with a residual pressure valve's function.

[Belgium R/T -68]

I think I have been misinformed at the shop concerning the function of the hold off valve. When I read on different sites selling them the purpose
is to delay the rear brakes a split second and NOT keeping the oil from going back like I was informed so I think the valve was correct mounted.

Will look for correct fittings today to be able to install the MP valve, the adjustable. Since in and out are marked that hold off function should be there aswell?

[b5blue]

Have you read the "Disco-Tech" article yet?  (It covers how that valve is adjusted.) I'm thinking the confusion is terminology the valve would be acting as/like a "hold-off" as it is a restriction in the line, same thing, ether or in name. This thinking would make elacruse's comment make sense to me as we are not talking about "residual pressure" valve. (Perhaps it's just me!  )   

[Belgium R/T -68]

I hate brakes, I hate brakefluid, I have the taste of brakefluid in my mouth. My wife always complains that I stink from it and it sticks everywhere.

Per

[b5blue]

  Tastes better than blood Per!

[doctor4766]

And can't smell any worse than gear oil