2003 Burb 4WD Z71 Standard Booster (not HydroBoost)

Every now and then, the Brake Pedal goes to floor, with only a slight braking force. After a few pumps (some time elapsed) it comes back firm and high as it usually is.

Can't decide it it's a problem with the Booster, or Master Cylinder

Your thoughts.

 

Booster... I had a 1997 Tahoe that had a very similar problem....You could do the master cylinder while you are under the hood. The booster for the 97 was nearly plug and play as there is no need to drain the MC, if you replace the MC you will need to bleed the brakes.
That was a 97 the 03 I wouldn't think wouldn't be that different, but the MC will likely have a proportional valve that may come into play during the bleed process..

 

Thank you for your prompt and informative reply

Given the age of the vehicle and, that it has 147K mi, I wonder if maybe a rebuilt Booster may do ?

 

I think an remanufactured one would do just fine...

 

Ok, I'll go with the re-manuf.

But I've been wondering...
This has happened about twice in a year or so, do you have any idea just what causes it ? I know there is a diaphragm and vac-valves that assist the pedal pressure, plus a hose which supplies the vacuum.