I have a slight problem with my brakes. When I'm on boost, the brake pedal is hard as hell to push down.

Not that I am braking under boost but if I drive like a maniac and push the brake pedal right after I come off boost there is a little lag before the brakes actually work.

It sort of gave me a little scare today, entering a corner at relative high speed and not being able to brake in time.

 

Check the check valve in the brake booster vacuum line. Also, make sure the valve is installed properly noting which side is which.

 

+1 on the check valve.

 

Thanks, I will try that.

 

Not sure if you have a LHD or RHD car, the brake hoses and check valve setup is different. The early LHD check valve setup had the check valve on the passenger side of the car by the turbos, this cooked the check valve and they had issues. Mazda did a recall with 2 new hoses that moved the check valve over to the brake booster/driver's side of the car.

RHD cars only have a short hose going from the brake booster to the intake manifold.

Either way, try and get a new Mazda part to replace it, otherwise get a good used one. This is NOT something you want to rig up or mess with, this is a serious safety issue.

Dale

 

Thanks for the replies guys.

It turned out the last owner thought it would be nice to swap out the brakebooster line with a straight fuel hose.

I had a checkvalve laying around so I went for a spin and now everything works perfectly.