C4 brake booster not turning on
06-28-2009, 05:44 PM
#17
Check the ABS pump and ABS control relays (in the relay board). If dated before 1991, should be replaced as the pump relay can (does) stick on and burns out the pump and wiring.
06-29-2009, 03:45 PM
#19
Nordschleife Master
A little bleeding . The pump pushes brake fluid into the bomb . Trace the fluid line from the pump to the bomb . If you see that the fluid is not going to drain from the line to the bomb , you can see that the air can be pumped from the system if the bleed nipple on the bomb is cracked open before the pump motor is turned on .
The air in the pump will go down the tube , into the bomb and then out of the bomb via the bleed nipple .
If you are getting rid of your old pressure switch can you send it to me ?
I would very much like to see how the switch inside works without cutting open one of mine .
The air in the pump will go down the tube , into the bomb and then out of the bomb via the bleed nipple .
If you are getting rid of your old pressure switch can you send it to me ?
I would very much like to see how the switch inside works without cutting open one of mine .
06-29-2009, 03:58 PM
#21
Nordschleife Master
Indy - Is this what you want to see? https://rennlist.com/forums/964-foru...internals.html
I wish to see how the electrical portion of the switch works .
From dfinnegan excellent work and photos , we can all see the "guts" and the action of the mechanical parts .
06-29-2009, 05:11 PM
#22
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A little bleeding . The pump pushes brake fluid into the bomb . Trace the fluid line from the pump to the bomb . If you see that the fluid is not going to drain from the line to the bomb , you can see that the air can be pumped from the system if the bleed nipple on the bomb is cracked open before the pump motor is turned on .
The air in the pump will go down the tube , into the bomb and then out of the bomb via the bleed nipple .
If you are getting rid of your old pressure switch can you send it to me ?
I would very much like to see how the switch inside works without cutting open one of mine .
The air in the pump will go down the tube , into the bomb and then out of the bomb via the bleed nipple .
If you are getting rid of your old pressure switch can you send it to me ?
I would very much like to see how the switch inside works without cutting open one of mine .
07-06-2009, 04:31 PM
#24
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07-15-2009, 09:06 PM
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Ok I am back in the game, parts arrived.
I read dfinnegan’s excellent write up on the Pressure Switch Replacement. I am unclear why I need to remove the pump. Can I just unplug/unscrew the sensor and bleed the system and be done? Would it be possible to use vice grips with a thin rag wrapped around the sensor to remove the old one or is super tight?
I do not have a full garage of tools like a wooden vice or even a good place to work so simple solutions are better. I am working in a parking lot with basic hand tools I can carry.
I read dfinnegan’s excellent write up on the Pressure Switch Replacement. I am unclear why I need to remove the pump. Can I just unplug/unscrew the sensor and bleed the system and be done? Would it be possible to use vice grips with a thin rag wrapped around the sensor to remove the old one or is super tight?
I do not have a full garage of tools like a wooden vice or even a good place to work so simple solutions are better. I am working in a parking lot with basic hand tools I can carry.
