james2747
Senior Member
- Joined
- Jan 26, 2011
- Messages
- 107
- Reaction score
- 31
- Location
- Newent, Gloucestershire
- Your Mercedes
- E270 CDI 2003
W211 E270CDi 2004.
I had read lots of warnings about deactivating the SBC system before attempting any work on the brake calipers … otherwise you could lose a finger or two.
I had the rear calipers off the other day (renewing parking break shoes) and ensured all doors closed, ignition key safely tucked away, etc. as recommended in many write-ups..
However, I needed to get in to the car after I got the new shoes on … to put it in neutral … so I could spin rear wheels to allow me to set the rear shoes adjusters properly .. and didn't want any drag from calipers, so they were still off the disc.
I therefore placed a piece of wood between the brake pads, the thickness being about 1mm less than the disc thickness, in case the system activated when I opened the door.
Sure enough … the SBC pump jumped in to life as soon as I opened the door and put key in ignition so I could get gear selector in to Neutral … but on checking the calipers, rather than finding the 2 pieces of wood being held in a vice like grip by the brake shoes … nothing!
They hadn't moved … still a 1mm gap twixt pads and wood.
Obviously no pressure at all was going to the brakes. I assume putting my foot on the brake pedal would have resulted in activation … but that would be normal and expected.
It was in this state for about 30 minutes … before I then opened door again to put it back in to 'Park' and remove key … more pump activation …. but no pressurising of rear brakes!
Can anyone tell me if this was normal … or was this just a glitch in the system and pressure could have been applied without warning to the calipers at any time … although I can't think of how this could occur.
I would add that the brake system is in good order and works fine in normal use.
I had read lots of warnings about deactivating the SBC system before attempting any work on the brake calipers … otherwise you could lose a finger or two.
I had the rear calipers off the other day (renewing parking break shoes) and ensured all doors closed, ignition key safely tucked away, etc. as recommended in many write-ups..
However, I needed to get in to the car after I got the new shoes on … to put it in neutral … so I could spin rear wheels to allow me to set the rear shoes adjusters properly .. and didn't want any drag from calipers, so they were still off the disc.
I therefore placed a piece of wood between the brake pads, the thickness being about 1mm less than the disc thickness, in case the system activated when I opened the door.
Sure enough … the SBC pump jumped in to life as soon as I opened the door and put key in ignition so I could get gear selector in to Neutral … but on checking the calipers, rather than finding the 2 pieces of wood being held in a vice like grip by the brake shoes … nothing!
They hadn't moved … still a 1mm gap twixt pads and wood.
Obviously no pressure at all was going to the brakes. I assume putting my foot on the brake pedal would have resulted in activation … but that would be normal and expected.
It was in this state for about 30 minutes … before I then opened door again to put it back in to 'Park' and remove key … more pump activation …. but no pressurising of rear brakes!
Can anyone tell me if this was normal … or was this just a glitch in the system and pressure could have been applied without warning to the calipers at any time … although I can't think of how this could occur.
I would add that the brake system is in good order and works fine in normal use.
