I think I'm having a brake vacuum leak with the D @ 4700 miles. When the vehicle sits overnight I get a heavy pedal feel before starting her. Then after start up the pedal feel returns to normal. Any thoughts as to what the failure is the vacuum booster pump, check valve or etc...?

 

There's no vacuum without the engine running.
Seems normal to me!

 

That's not true. When the engine is running, it creates vacuum and as long as your foot is off the brake when you shut the engine off, there should be residual vacuum pressure.

When I start my D after it has been sitting overnight, there is no change in the pedal feel on that first 'depress brake to start' than when the vehicle is running.

D3, you may have an issue.

 

Thank you, any idea what the issue may be? Anyone else having this issue?

 

Every vehicle I've ever owned (with power brakes) has had a different feel on on the brake pedal without the engine running.
Unless you're have real braking issues why are you concerned about this?

 

Because there is a vacuum leak! And Leaks get bigger! How is this not a real problem? I like my vacuum power assisted brakes on a 5,200 lbs vehicle or better yet while towing a 3,500 lbs trailer with my family in the car traveling at 65 on the highway and having no brakes or limited braking ability!

The pedal feel changed early this week and is distinct and causing issues with the vehicle starting function. When I first get in the D in the morning the pedal is extremely firm and I have to press hard to de-activated the lockout function to start the engine. Once started the pedal drops to it's normal position. No other abnormal behavior is found or logged after. From my understanding of a vehicle braking system the vacuum should not bleed out of the system while the vehicle is off. Yes you can bleed the vacuum by pumping the brakes a few times and the same firm pedal feel can be created.

 

I'm thinking Didhe... is missing the fact that it was fine all along and this change just happened.

Off to the dealer, assuming it's under warranty.

 

Straight to the dealer bro... Any questions about potential brake issues should be addressed asap!

 

Already made an appointment. Just looking for facts so I have some knowledge of the issue or possible TSB / Recall.

 

Looks like 2 other similar complaints have been filled with the NHTSA.
http://www-odi.nhtsa.dot.gov/owners/SearchVehicles