Hello,

After more than a year of neglect, I am now trying to bring my beloved WJ back to shape, and prepare it for winter driving.

All is proceeding well, but now there is a constant hissing coming from, I believe, the brake booster. It goes away when I press the brake down.
It is not affecting the breaking per se, but I would like to get rid of the noise, if possible, without having to change the entire part.

What are the best steps to follow to troubleshoot the situation in a gradual way?

Any advice and/or link to post would be greatly appreciated.

Thank you

P.s. I recently posted with a new account about the horns going off (now that's fixed, although I am not sure the battery is completely fine, I might have to change it), but today I was able to log into the forum with my old account.