Is there a way to test if brake booster is leaking internally?
05-02-2016, 03:36 PM
#1
Drifting
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Location: Massachusetts
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Is there a way to test if brake booster is leaking internally?
Wondering if my brake booster is shot. Is there a way to test using a mightymac? Don't own one but will get one if someone can tell me how to test the brake booster with it.
05-02-2016, 07:22 PM
#2
Race Car
Easy, use the adapters with the tool to go from the hose size to the vacuum tool nipple.
Pull 15 inches of vacuum and see if it holds.
Without a tool, run engine then kill. Pull hose at check valve and you should hear the booster sucking in air if it is good. The check valve would have held the booster under vacuum without the source from the engine running.
To rule out the check valve, clamp hose with needle nose vise grip pliers while engine running then perform same test.
If vacuum present when unplugging check valve with the plier clamped on the hose but not in the previous test with out the pliers, your check valve is bad.
T
Pull 15 inches of vacuum and see if it holds.
Without a tool, run engine then kill. Pull hose at check valve and you should hear the booster sucking in air if it is good. The check valve would have held the booster under vacuum without the source from the engine running.
To rule out the check valve, clamp hose with needle nose vise grip pliers while engine running then perform same test.
If vacuum present when unplugging check valve with the plier clamped on the hose but not in the previous test with out the pliers, your check valve is bad.
T
05-03-2016, 03:52 PM
#3
Drifting
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Without a tool, run engine then kill. Pull hose at check valve and you should hear the booster sucking in air if it is good. The check valve would have held the booster under vacuum without the source from the engine running.
To rule out the check valve, clamp hose with needle nose vise grip pliers while engine running then perform same test.
If vacuum present when unplugging check valve with the plier clamped on the hose but not in the previous test with out the pliers, your check valve is bad.
T
05-03-2016, 05:37 PM
#4
Drifting
You can always just pull the check valve out on the brake booster the next morning or hours later and see if it makes a swoosh sound like it was holding vacuum. Mine held without issue after a year and a half before I made my way to that part of the car.
05-03-2016, 11:03 PM
#5
Race Car
The booster will be under vacuum when you start the car.
The sound of it sucking air when you pull the check valve (assuming CV is good) will be air rushing in as booster goes back to atmospheric pressure from vacuum.
The Mityvac will test it fine too and is a handy tool to have for other purposes.
T
05-03-2016, 11:06 PM
#6
Race Car
Ya know....I never think of relaxing a booster when storing a car but it's probably a good idea.
The vacuum seal sits there holding against the spring force inside the booster all that time.
T