The message to which you are about to reply is shown first. GO TO REPLY FORM



 VIEW    REPLY TO THIS MESSAGE    PRINT   SAVE 

740 faulty brake booster? 700 1990

uid 6185's pic
posted by  blue940 on  Thu Jan 31 21:56 CST 2013
Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
last visit: Sat Oct 18 21:11 CST 2014
[RELATED]

Car is a 1990 740GL with ABS.
Symptoms: When the brakes are applied there is a distinct air hissing/rushing sound which stops as soon as the brake pedal is released. When the engine is turned off with the brake applied, the pedal almost immediately starts pushing back against my foot and goes almost rock-hard in 4-5 seconds.
The car also exhibits an occasional high idle (1000+ rpm).

I checked the vacuum hose from the manifold to the booster and there are no cracks or splits. I removed the check valve and can blow air from the booster side through to the hose side but not back the other way. I assume this is correct since I compared it to my 940 which was the same. The check valve itself is not cracked or otherwise damaged.

Is it possible to remove and dismantle the booster to check for a broken diaphragm? Is there any other way to be certain this is a faulty booster? Is the check valve known to leak around the rubber gasket on the booster?

I would really appreciate any help people can offer.






USERNAME
Use "claim to be" below if you don't want to log in.
PASSWORD
I don't have an account. Sign me up.
CLAIM TO BE
Use only if you don't want to login (post anonymously).
ENTER CAPTCHA CODE
This is required for posting anonymously.
OPTIONS notify by email
Available only to user accounts.
SUBJECT
MODEL/YEAR
MESSAGE

DICTIONARY
LABEL(S) +
IMAGE URL *
[IMAGE LIBRARY (UPLOAD/SELECT)]

* = Field is optional.

+ = Enter space delimited labels for this post. An example entry: 240 muffler


©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.