MB4runner

Hi guys, new to the 3rd gens, I have a 99 4runner v6 sr5, after the cold weather started I noticed my brake pedal was rock hard when starting it up from cold.
(The pedal goes down once, after that it's rock hard for a few minutes)


So after searching, I believe the problem is the brake/vacuum check valve. The threads I read mention it is either inline with the vacuum hose running from the booster to the intake manifold, or it's on the booster itself. Problem is I don't see it in either of those places and I don't even really know what it would look like.

Anyone have a picture or can help me! Thanks!

Trail100

Plastic piece that goes into rubber grommet at booster.

Qyota

Yes, it's at the end of the vacuum hose running to the top left side of the booster. Loosen the left side master cylinder bracket nut, just enough to rotate the catch away from the check valve. Pull the hose off, then grab the check valve (which is actually metal, not plastic) with a pair of pliers and wriggle it out of the booster. Then pop out the grommet. Replace both. Rotate catch back onto the check valve stud and tighten the nut. Reattach vacuum hose.

I just did this the other day - piece of cake.