|
Mark G
Date registered: Jul 2006
Location: Ft. Lauderdale, FL USA
Vehicle(s): 1985 280GE LWB AT
| Brake Booster 460/M110
Brake Booster 460/M110
I have some doubts about my Brake Booster. Wonder if anybody out there has some experience in this area. Air seems to leak out when you push the pedal to full extension and hold it. I am speaking of inside the cabin where the piston comes out of the firewall. There is a rubber boot covering it. If you push the pedal all the way down and rev the engine, it does move the brake pedal back and forth but not a lot.
I recently rebuilt the master cylinder, replaced brake lines, and bled everything with some good improvement but still feel I am not getting the braking force that I should. When pressing the brake pedal you can hear pressure moving through the system very well. Just can’t remember if it should be as audible as it is.
Thanks
|
|
| |
|
fernweh
Date registered: Apr 2006
Location: Calabasas, CA - Centenario, BCS - Luebeck, Germany
Vehicle(s): Few Mercedes-Benz, a Toyota Amphibious and a Vespa
| RE: Brake Booster 460/M110
Hi Mark,
The rubber boot you see is just a dust seal, it might even have a tiny hole in it to let the air out when pressing on the brake pedal. you might hear that noise.
An easy brake booster test is: shut down the engine and press a few times the brake pedal until it become stiff (to use up the stored vacuum). Then again press down on the brake pedal but keep it pressed down. Now start the engine and find out if you can push the pedal even further with the help of the "new" created vacuum. If yes, the booster might be ok. If not check all the vacuum lines/plumbing including check valves before pointing at the brake booster.
Good luck |
|
| |
|
HCrous
Date registered: Dec 1899
Location:
Vehicle(s):
| RE: Brake Booster 460/M110
Out of experience it is either you diaphram that is broken or the actuator valve inside the booster. A good brake shop should be able to rebuild it with ATE components. We do it here all the time as a new booster is ridiculiously expensive. |
|
| |
|
elevatorbernie
Expert
Date registered: Aug 2006
Location: Vancouver B.C. Canada
Vehicle(s): 1989 280GE
Posts: 1347
| RE: Brake Booster 460/M110
My G has a similar problem. The pedal sinks about an inch while idling at a stop. |
|
| |
|
Mark G
Date registered: Jul 2006
Location: Ft. Lauderdale, FL USA
Vehicle(s): 1985 280GE LWB AT
| RE: Brake Booster 460/M110
The dust cover is open ended and not sealed. I definitely can hear air seeping out long after any air should be released from the dust cover/boot. I understand Boosters are expensive and sure do not want it to be a problem. There is a check valve on the booster with a vacuum hose that runs to the crankcase. It is possible this old valve could be leaking. However, does not account for the air being released from the inside foot well.
I have done the workshop manual test outlined in the workshop manual, which states the following;
1. With engine switched off, operate brake pedal aprox. 8 times until vacuum no longer exists.
2. Hold brake pedal in partial braking position and start engine. Operate accelerator.
3. If vacuum exists and the brake pedal yields perceptibly, the brake booster is in order.
It seems to pass the test based on the only G-Wagen I have ever driven…mine.
 (brake dust boot.JPG)
 (brake dust boot.JPG)
Attachments
----------------
 brake dust boot.JPG (144KB - 2 downloads)
brake dust boot.JPG (144KB - 1 downloads)
|
|
| |
