I replaced the hard rubber hose from my uim to my brake booster with a silicone piece from hose techniques. ever since, when i am in boost, it's really hard to push the brake, like there was no check valve or anything, and when it falls into vacuum, i get full pressure back. i couldn't find a check valve, so i tried a pcv valve, and it made it worse. is there any reasoning behind this or an easy fix??

 

There is a check valve -- you need vacuum in the brake booster and you don't want boost. The check valve blocks boost, and maintains the vacuum even when you go to 0 psi for light acceleration, etc.

-Max

 

The check valve has been moved from the brake booster line that connects on the passenger side to the UIM, to the one on the drivers side that connects up to the hard line (I just replaced mine with OEM over the winter).

Check the brake booster line on the driver's side to see if it contains the check valve (just try to blow threw it both directions).

 

okay, i'll have to check it later today. if i order the lines from mazda, will they have the check valve already in them? or will i have to order it seperately?

 

The check valve will already be in the line. The hoses come together as a kit and the price was $7 from Malloy Mazda.

 

thanks, i shall order tomorrow, i appreciate it man

 

got them and installed. problem solved. also, for some reason, my idle seems more stable now. is this possible with the addition of a check valve? the new set came with the valve on the booster side, my old set had the check valve on the uim side, which is the one i took off. kinda weird

 

Can you remove the check valve? I just did the hoses as well and noticed this post. I'm looking for the old hose now. Just curious if it can be taken out and put in the silicon hose. Thanks!

 

you can probably buy one from a local auto parts store. i couldn't find one so i thought maybe a pcv valve would be a substitute, but it wasn't. anyways, u might be able to cut the old one out of the hose, just feel for the big lump in it