I was doing a hose job on the FD and found that one of the brake booster vaccuum lines has a check valve in it. Is this necessary to keep vaccuum in the booster (to prevent run out) or has someone removed it and had no problems?

Thanks!

 

It's required.

 

Think about it for a second:

You have a turbocharged car. This means you will have POSITIVE pressure under boost. You need that one-way check valve to keep from pressurizing your power brake unit. It works on vacuum.

 

so what exactly will happen or can happen if say you replace the hose and didnt know it had a check valve in it? Yes I did this.I cant really say anything has changed so thats why im asking.

 

hmmm.I think I just realized why im getting this whooshing sound right in front of me in the engine bay.The booster is pressurizing.Which also means im also losing boost right? or would it just cause some lag since the system is pressurizing extra space?

 

whoa.that was friggin weird.The last two posts before this one were actually mine.But for some reason the forum made a different screen name.Thats weird.Mahjik if you see this maybe theres a bug or something.

 

hmm no answers yet.could it be that ive answered my own question?
Feel free to chime in guys.

 

bajaman, I was wondering if there wasn't a second check valve within the booster(like on other cars) in which case the check valve in the hose to the booster is redundant (which would not surprise me on this car).

I realize that a check valve has to be in the system or the booster will lose vacuum as you boost (hope you don't have the use the brakes right then!). Sounds like a great way to blow the diaphram in the booster!

Thanks for the sanity check.

 

Nope, there is only one valve. The valve was moved from the passenger's side to the driver's side line as a TSB. Cars that never had them replaced will find the check valve on the passenger side.

speeddemon7, yes, that is an ongoing problem which the Admins are working on...

 

well I guess ill try to find a check valve for the hose since I dont have one right now.

 

Just call Ray:

Malloy Mazda
1-888-533-3400
Talk to Ray Crowe

The kit for both hoses (passenger and driver side with check valve already in place) is about 10$.

 

umm so theres actually two check valves then? one in each hose?

 

One check valve, two hoses.

 

ok I get it.So it may vary where the check valve is right.I just have to check both hoses.I think I may be lucky and still have the hoses around somewhere.i hope so anyways.Just means I dont have to buy new ones.Thanx mahjik for the help.

 

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

:-) neil

 

I had the line with the check valve in it fail. The result was LOTS of manual leg pressure to get the brakes to work (and a damn scary drive home from the canyons here).
I drove back giving me like 10 car lenths at 40 mph and used lots of muscle to stop the car.

I didn't know what the problem was until the next day (nor that there was a TSB for this - probably my fault). Definitely not a fun way to learn about these 2 hoses.

 

Thread bump!

I've had my fd for a few years now and come to find out the recall for mine was never done. The fuel line leak recall was also never done but my local mazda dealership has no one experienced enough to be willing to tackle this job. Nor would I be trusting them with my 93 r1 low mileage fd. I was able to recently get a hold of Ray and able to order all of the parts for the fuel recall kit. I will be tackling it myself for this part, as for the brake booster hose recall kit. Unfortunately Ray said that the brake booster hose recall kit is NLA, so I'm trying to find other ideas on how to get the brake booster check valve recall done myself on my fd. Just don't want to make a mistake and have no brakes. I know I have to replace both hoses on driver side and passenger side.

Here are the ideas that I have come up with and wonder what are everyones thoughts:

1. Get universal brake booster hose from what I read usually a 11/32 size, cut it to length and use an external check valve for the driver side. I believe the passenger side just put the hose in with no check valve.

2. Would using brake booster hoses from other mazda cars work?
example: using something from 929 or miata, as long as i can have the check valve on the correct side and the length of hoses are able to be made to match. (Even if trimming of the hoses is needed)
My follow up to this would be, i am not sure if this would work as I assume all check valves have different pressures that it can hold before opening. Thus this may not work for me.

3. Open to anyone else's idea on how to get his done as a safe fix is truly appreciated.