brake bleeding problems

In case you wondered what the one-way valve looks like...

Well, I just checked and the line from intake into the hardline, and out of hardline into booster is ordinary heater hose line
I can blow through it both directions with no resistance, light shines right thru it from end to end

Clues tell me that piece is not in there
could this be part of my problem?

Also, I talked to the guy at oreillys and he said he found the "proper" brake lines, the first ones he sold me were wrong
They fit a crap-ton better, also one actually tore up threads on brand new master cylinder, so they warrantied out the brake lines, and master cylinder
Gonna start from square one again in the morning as far as bleeding

Yep, sounds like your problem... at least with the brakes not holding boost. You can get a new brake hose with the valve or get one form a junk yard... I have the valve or a hose with a valve available if you can't find one.

If I was to search for one

What should I search for?
I can't seem to find anything on it

Jim Ellis Mazda is a good place to look... $26 from Mazda.



Mazda part number - UB3943640A (43-640)

I looked up for 89, I don't know your model year.

1990

I think that will be the same hose/valve part. Yes, you shouldn't be able to see through, or blow through except one way (and that's also tough, and not too good-tasting).

Go new if you can't lift one from a parts yard; with shipping, price to send a used one approaches that of new.

EDIT: Thanks, Dan - didn't know what was actually in there !!!

RCogan, this is Chris the guy having the same problem that was talking to you on facebook. Thought I'd pop on and see if anyone here had advice. I ran out to check my hose hoping I'd find no check valve and that could be a source of my ailments. No such luck for me, the valve is there working properly and not tasting to good.

Do you guys have any other suggestions? I've got the same symptoms. No real pedal pressure after a day or two of swapping master cylinders (I'm on my third) and the same thing happens every time. Works great the first day or two then right back to crap. No visible leaks anywhere. Every once in a while (very rarely) if I pump my brakes while braking my pressure will build up. As I take off again and come to the next stop, right back to crappy super soft pedal. I've gone through at least two bottles of fluid from flushing the brakes, so I know there is no old fluid in there. Lines are older but in decent shape, no dry cracking etc. Aside the 64 Comet I was so excited to get running I forgot to check the brakes before taking it on it's maiden voyage (it had a dead master cylinder and busted wheel cylinders) I have never had a vehicle with such crappy brakes and that's bad for a daily driver.

Chris, I had a guy local tell me an idea
get a set of fuel line pincher clamps(or equivalent that will stop flow of fluid)
clamp all 3 rubber brake lines. 2 front and 1 in rear
Try to pump up pedal, if it works, unclamp one hose at a time and pump pedal a few times, see if it stays pressured up, or builds up
if so, do the next, by doing this, it would/should tell you if you have a caliper or wheel cylinder leaking(even if you cant see it) if nothing else, it will eliminate that as problem
Also, have read somewhere when you bleed brakes, put something under pedal to make sure it doesnt go all the way down, that may damage master cylinder(was on different vehicle, mazda experts chime in if it is or isnt same on these trucks)
Also, make sure your holes in feed lines into calipers are lined up with the hole in hose to get proper fluid circulation

BEFORE you bleed the brakes be sure to manually adjust the rear brakes.

Also, when installing a new master cylinder you MUST make sure your brake booster is set properly. Here is a sample of how to do that...

Blocking the pedal from going to the floor will only drastically increase your bleeding time as the reduced pedal travel will not allow you to get a "full" push. The only way to damage the master is if the booster push rod is adjusted incorrectly.

It sounds to me you have either multiple issues or you have not performed all the diagnostics needed to determine the real problem.

I would start by getting a new one way valve on the booster then bleed the brakes appropriately then check for leaks etc.