Brake booster front seal grease?

[micbrody]

Should I have grease on front seal and/or bushing that is between brake booster push rod an master cylinder? If so, what kind of grease?

The reason I ask is: I replaced leaking brake booster. When I removed master cylinder there was grease covering the bushing. I didn't understand why. When I installed new booster, I did not add any grease. The new booster works great; and car starts immediately.......but only 8/10 times. I found if it sits for over 12-24 hrs, I am more likely to have difficulty. My theory is that I still have a tiny leak.
As an experiment, I waited about 24hrs, and then just before restart, clamped vacuum hose from engine. Car started immediately. Next day, I did not clamp; car took 5-10 seconds to start. I starting thinking that maybe the grease helps seal front seal.

[alexg2368]

I am about to replace my brake booster any advice on how to do this.

[micbrody]

Yes, I can help!

First, the post about maybe losing suction in new brake booster turned out to be (mostly), a red herring. My trouble with starting car ultimately turned out to be flakey fuel pump that could not deliver pressure to fuel lines. I did find that the check valve on new booster was totally non-functional; AR sent new valve which solved problem.

As for specifics: anything you have questions about?

[alexg2368]

What do I need to move to get the booster out?

[micbrody]

I detailed much of my experience in lower link. (If link does not work, look at February 10, 2016 post by me "micbrody"

http://www.fiatspider.com/f15/viewtopic.php?f=3&t=32629

[alexg2368]

ok thanks

[micbrody]

From memory: things that were difficult was the physical removal and replacement of booster. Space is VERY tight; but I think I detailed what I had to disconnect.

The hardest thing (which I did not mention in thread) was the reattachment of spring that is on brake pedal linkage under dash. Easy to remove; but extremely difficult to reattach because of cramped space; awkward contorting of body ; not easy to grasp