Where is the brake booster check valve located on a 1998 Accord EX (4 cyl, VTEC ULEV)?

This car stumbles a bit coming into a stop. I found that if, while going up a hill, it is put into neutral, allowed to glide to a stop, and then held in place with the parking brake it is fine. But step on the brake once at that point and it immediately stalls. That suggests to me that the check valve is bad.

Also, does Honda even still make this part? If not, what would be an acceptable generic?

Thanks.

 

I don't drive an accord from this era, but i thought it was a grey/white/black plastic part in line from the vacuum line coming off the intake.

To test it, i would think that you would run the car to fill the vacuum booster, turn car off, let it sit for 1 min and if you have break boost, it should be fine.
You could also just go out to your car with the engine off and press the brake pedal to see if you are holding boost.

Often, but not always when a booster goes bad, you can hear an odd whistle coming from a ruptured bladder.

I do hear that clogged egr passage ways will cause poor idle, if there is not an issue with the boost.

 

There is something that fits that description attached to the driver's end of the fuel rail. A hose goes from there to the top of the intake manifold, or maybe it is still the throttle body, on the engine side of the throttle. The other end disappears down behind the engine into the unknown. Ie, I cannot see what it attaches to. Presumably somewhere down there they have the brake booster mounted. I did check with Honda and they don't sell brake booster check valve's any more. It probably doesn't matter though if some generic valve goes in, as this is a one way valve, more less like a PCV valve.

Edit. Looking closely at the brake booster, which is between the master cylinder and the firewall, there is a vacuum hose which goes directly from the booster to the intake manifold. Nothing in that line, just hose. At the two ends it looks like it is just stuck onto the usual sort of nipple for a vacuum hose. Maybe the valve is built into the booster itself???

Edit2. Apparently the check valve is in that hose. Feeling along it there is a stiff section in the middle, and I found one for sale on Ebay, showing the hose, but listing it as a check valve. Honda no longer sells these though.
Also, the car does not always stall on the "glide to a stop and then press the brake" test. So if this part is bad, it may be intermittently so.

I can't hear much above 2kHz. If the whistle is lower than that then it isn't present. My wife still hears well though, and it's her car, and she says there is no whistle.

 

Yes, that is the hose that it would be, in Edit2. Besides the test I listed above, you can also take the hose off of the brake booster (not the intake) and put a large enough bolt and possible a hose clamp into the hose to block off any vacuum. This will make the brakes very hard to press/activate, but if the stalling goes away, then that would indicate that you are certainly looking in the correct place. Start with the one way valve and if that does not fix the issue, then it could still be a brake booster going bad. *You should be the one testing the car with the hard brakes as she won't be expecting it.

I am not convinced that this is the issue, but it is a good place to start. There are idle circuits and possibly even a temperature or air activated one bolted onto the intake as well as the EGR system built into the intake manifold.