If your pedal goes to the floor the problem is NOT the vacuum check valve. It's function is only to hold some vacuum for a short time after the motor is shut down or during periods of low vacuum so you would still have some boost for the pedal. The real problem is either air in the brake system, a leak, or a bad master cylinder. You can rule out a leak if the level never goes down. Inspect the front bulkhead for moistness which would indicate a leaking master cylinder which means it is bad. If it looks dry flush and bleed the brakes. If that still won't correct the problem then the master cylinder is leaking inside and must be rebuilt or replaced. BTW you could pull the vacuum hose off the booster and look inside the hose. If it is wet that means the master cylinder is leaking into the booster which also means you need to do the master cylinder. The tip-off is if the brake fluid is going down, it only needs to be topped off if it is leaking out (or over a long period of time to take up brake pad wear). If you find you are always having to add fluid you have a leak which must be fixed ASAP. Remember to try to use Castrol GTLMA DOT 4. Same stuff for the clutch (if you have a 5-speed). David Teitelbaum vin 10757 --- In dmcnews@xxxxxxxxxxxxxxx, "Adam 16683" <acprice1@xxxx> wrote: > I can put the brake pedal almost all the way down the first time, > then the second pump is only about halfway. This is after the car was > sitting for a weekend. > > What part number is this check valve in the dmc parts guide? > > thanks, Adam 16683 >