cooliomo

i have an 86 n/a rx7 today i was planning to change the brake booster vacuum line because it looked old and dried up!, so i go to pull it off and i notice some kind of valve or orfice tube in it what is that, and do i need to special order it?

satch

iTrader: (1)

It's called a check valve.I think some posters have used ones made by other manufacturers such as GM,but you are probably better off by getting one by Mazda.

Blackfc3srx7

iTrader: (1)

As long as its a n/a you can replace it with hose straight from the auto parts store. That check valve is mainly for t2 models because of the boost that the turbo throws into the system and you would have problems boosting and braking. There is another thread on here where I found this.

cooliomo

r u sure? i don't think they would have put it there for no reason

satch

iTrader: (1)

If I remember correctly the hose has some serious bends in it and any rubber hose will not suffice. I think the dealership can provide you with one for about twenty bucks. If you find that it is too much I'll make up the difference.

Blackfc3srx7

iTrader: (1)

I actually don't mean a rubber hose, I mean an already molded or bent hose that matches the bend in the hose he is replacing. I searched for is about a month ago wondering the exact same thing.

I replaced mine without the check valve and no problems at all. I actually have better braking because my hose was bad. You can order it from the dealership but I went the other route.

misterstyx69

iTrader: (142)

Boy oh boy....the Check valve is in there for a reason..it prevents the air from Backfeeding on the booster,and also so that your brakes don't "ride" while the Brakes are NOT in use...and Try to put that Hose on Backwards..you get almost no Brakes at all.,because the vacuum of the engine is not allowing the Booster to Work,when you push the pedal Down,it's like super Hard manual brakes.(been there done that TOO)..the Manufacturer Always have a reason for Little **** like this..don't tell people they don't need it.If you want to Shortcut the life of your brake Components go ahead.It's your Car.but when you start telling others that you can take **** off,that rightly should be there..then NO..that is when you Put someone else's Life into a bad Situation...It is Kind of Funny that the check valve In question is on an N/a Car as well.And that the Hoses for N/a and TII are Different also.,So I am wondering Where MY turbo is,when my Car seems to have a Check valve on the hose.

cooliomo

hhmm good point, i think ill just call the dealership or a rotary shop and get one with the check valve OEM Baby!

clokker

iTrader: (2)

I call shenanigans.
Either your replacement hose has the check valve and you don't know it, a PO put a check valve on the engine side of the hard line or you simply don't know what the brakes are supposed to feel like.
A vacuum assisted brake system absolutely requires a check valve.

Most makers don't use the internal "pill" type of valve- they use valves that look like little fuel filters spliced into the hose.
There is nothing model specific about check valves, they are totally generic, so if you want to use the valve from another car you can just cut the hose and add it in but in any case, you must have one.

pfsantos

iTrader: (1)

Styx and the others are mostly right. You NEED the proper hose w/ check valve.

At WOT, how much vacuum are you producing? Hook up a vacuum gauge to your intake and find out. You'll have very little. If you go on the brakes right after a bit of fun, you won't have much assist when you need it the most.

pfsantos

iTrader: (1)

- 86-88 Mazda RX-7
- With and without ABS

NA
Hose near booster (43-640) FB01-43-640

TII
Hose near booster (43-836A) FB45-43-836A

Check valve (43-770) FB44-43-770

Looks like the TII uses a separate check valve and the NA's use one built-in to the hose.

pfsantos

iTrader: (1)

86-88 FSM (see my sig. for link), Chapter 11 - Brakes, page 18.

"Check valve
......Note: The check valve is pressed into the vacuum hose, and there is an arrow on the hose surface to indicate the installation direction."

Does not specify whether NA or TII

Blackfc3srx7

iTrader: (1)

I was simply stating that I replaced mine with no check valve after reading another thread on this exact same thing with no noticable affects. I am sorry if I am putting someones life in danger?! I did not mean that. By all means get the check valve and be done with it.

Blackfc3srx7

iTrader: (1)

https://www.rx7club.com/showthread.p...+booster+valve

https://www.rx7club.com/showthread.p...+booster+valve

Just so you know im not pulling it out of ***.