Re: new brake booster seems like it's failing - Bulletin Board

[General | Members | C900 | 9000 | NG900 & OG93 | 93 | 95 | NG95 | 99 | Sonett | Vintage Models | Performance | Detail | Clubs & SOC | Other Cars | Books Movies & Music | Chat | FAQs | Gifts | Member Photo Galleries | Member Directory | Classifieds | Service/Mechs | Manuals | *Buddy Registry | *Mileage Registry | Polls | What's New | Raffle | Photo of the Month | Sponsors]

C900 Bulletin Board
1979-1993 & 94 Conv
(Search Author's Posts: e.g. Keyword:Author)*Members Only

[Main C900 Bulletin Board | Post Followup | BBFAQ ] [ Prev by Date ] [ Next by Date ] Member Login / Signup [Most Recently Edited Photo Galleries]
Re: new brake booster seems like it's failing
Posted by S Carlson [Email] (more from S Carlson) on Mon, 7 May 2018 14:17:31

In Reply to: new brake booster seems like it's failing, brownerbrowner, Mon, 7 May 2018 06:23:10
Alert me when someone posts in this thread:

It is possible for a brake booster to fail without a vac leak. There is internal valving that can fail. The internal valving is responsible for the pressure differential between vac-side (front) and atmosphere-side (back) of booster. It's designed to let a little of the atmospheric pressure from outside the booster into the booster when you push on the brake pedal. This isn't enough to make the engine surge, but if it's not getting in (or if it's getting through to the vac-side) it could be a problem.

Other thing to check is the non-return valve (turbo cars only). Make sure boost isn't getting into your booster!

If you've ruled out the easy stuff, it's possible that the rebuilt unit you got has some problem within it. Internal valving on these is a bit of a black box. I asked Booster Steve (specialist of Dewey's Booster Exchange in Portland) and he said he usually doesn't take the internal valving apart unless absolutely necessary. He said the usual protocol is to inject grease, repair external seals, and test. It could be that Cardone did this, and the grease they injected filled up some pits in the steel or deformities in the rubber within the internal valving, and then it tested fine. Now that the grease has settled it's not working well anymore. Doesn't Cardone have a lifetime warranty? You might want to check to see if you could get your rebuilt unit replaced.

posted by 65.112.10...

Posts in this Thread:
Alert me when someone posts in this thread:

Post a Followup

No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.

Name: Member Login / Signup [Most Recently Edited Photo Galleries]
E-Mail: (Optional)
Re-Enter E-Mail: (Confidential & Secure - Not revealed to other users!)
Note: Please check your spam folder for BB responses.
If you use GMail, follow these instructions from Google so that they appear in your regular inbox.


Posting rules are simple - No for sale/wanted ads or live auctions may be here - use the classifieds.
You may not cross-post your message to multiple BBs.
Personal attacks, insults, or flaming are not allowed.
Site Members do not see any red text, inline ad links, skyscraper ads, box ads, nor anti-spam check.

Message: (please no for sale/wanted classifieds - post those in the TSN Classifieds)
To add inline links to your post, use [link][endlink] or use the Optional fields below.
To add inline images to your post, use [img][endimg] or use the Optional Image Link field below.

Optional Link: (e.g.
To promote your own Saab site here, you must have a link back to The Saab Network.
Link Title: (Optional)
Optional Image Link: (e.g.

The content on this site may not be republished without permission. Copyright © 1988-2018 - The Saab Network -
For usage guidelines, see the Mission and Purpose Page.
[Contact | Site Map | on Facebook | on Twitter | Shop Amazon via TSN | Site Donations]

This is a moderated bulletin board - Posting is a privilege, not a right. Unsolicited commercial postings are not allowed (no Spam). Please, no For Sale or Wanted postings, SERIOUSLY. Classifieds are to be listed in The Saab Network Classifieds pages. This is a problem solving forum for over 250,000 Saab owners, so expect to see problems discussed here even though our cars are generally very reliable. This is not an anything goes type of forum. has been a moderated forum since 1988. For usage guidelines, see the Mission and Purpose Page. Please remember that you are not anonymous. Site Contact | Site Donations | Other Sites by SP -
Your address is: - Using CCBot/2.0 ( - Logged.
Site Members do not see red text instructions, skyscraper, nor box ads.
Click here to see all the Site Membership Benefits!