Check valve in brake booster line?
 

I just noticed that my 94 R2 does not have a chack valve in the brake booster line, should there be; like the 2nd gen?

Thanks

Hai

Are you sure it's not... its embedded in the line that goes from the firewall to the booster... you can feel the lump.

If it wasn't there, you'd know it. They can fail, and when they do, braking capacity is significantly reduced.

The FC has an obvious, external check valve. It's built into the rubber line on the FD.

Dale

yeah, there is one there.

Thanks

so you definatley need the check valve for your brake booster line? I was thinking of replacing the lines.

You deffinately need it. The power booster doesn't like 10 psi. on it. Mine made all kinds of wierd noises when I replaced the lines with silicone, luckily I kept the original and put it back on. Jack

If you don't have it, two things will occur:

1. You'll get an irritating fuel smell, and will spend hours checking injector seals, lines, and charcoal canisters looking for it with no success.

2. When you get on the throttle, it will literally suck boost right back out of the brake booster. The effect being that you'll nail it, then when you let off and need to slow down, you'll have very little brakes for a moment until the booster refills.

Ask me how I know.

Just get an "external" Viton valve like the ones that Dale is selling. I'm going to be doing the same thing, just haven't picked out the valve yet, but McMaster Carr has a good selection.

Why not just re-use the original valve (cut it free and stuff it into the new hose), just like you would re-use the "pills" in the WG & PC lines?

I was thinking of doing that...I have a braided line tha I was going to replace it with so I don't know if that would really work.

Good luck shoving it in to a line that's tight enough that it doesn't move or shift under 15 psi of boost. It's TIGHT.

anybody have a picture of where this pill really is? I have fuel smell but only under boost. I might check the easy stuff first.

It may even be molded in, not inserted. Has anyone ever cut one out before?

It's in the black rubber line coming off a hard line on the firewall, and rigtt into the booster. Can't miss the line, and you can feel the lump in it... right in the middle someplace

They can be cut out and used in a new line,be sure to put it in the correct direction .

you can look in the hose and see it...it's the hose with a bulge in it.

At some point they changed the location where they put the check valve. Mine ('93) is on the driver side near the brake booster.

Yes the check valve can be cut out and inserted into a new hose.

It is recommended however that you not use silicone hose for this as the wall thickness/rigidity is insufficient.

I did, it came out pretty easy when I cut the hose in one side of it and jus slide it of.
I put the same vavle on a new hose, real tight but doable. Kept the hose in hot water for a while so I can easely insert the same valve in...


:peace:

Thats where we've been saying it is... on the line going from the firewall to the booster... drivers side.

Cool. I'll look into it. Anybody know how much does it cost from the dealer? Also, how common is the failure of this check valve?

The FD's original brake booster check valve was on the passenger side of the engine bay and was prone to failure - this is the brake system recall. The recall kit includes the 2 hoses for the brake vacuum system.

I would reckon you could get the recall kit with the two new hoses VERY cheap. Most of the recall kits are very reasonably priced.

The check valve in the line is designed not to fail. Mazda had to do a recall since the original design *did* fail - this is not cool with the DOT.

You do have to make sure you do a good job if you replace those lines with an aftermarket setup - there's a reason the DOT got involved and Mazda did a recall, a failed brake booster check valve could result in an accident. The stock lines are actually very robust and should last a VERY long time.

Dale

11 dollars including tax from the dealer, for both hoses, sold as a kit.



:peace:

wow, thas pretty cheap. Might just get new ones just to be safe.

Mine was under $6 from Ray @ Malloy.
PN# FDY2-43-480.

:-) neil