|
|
|
|
| Author |
|
|
Registered
Join Date: Oct 2000
Location: Nor-Cal
Posts: 4,403
|
I think my brake master cylinder is dying
My brakes have been working fine, and I just flushed the fluid less than 3 months ago. Plenty of rotor and pads left, and all of the sudden my brakes feel really weak. They still seem to be stopping fine, but I have to floor the pedal. There is no feel untill the last 1/4 inch of pedal travel. The master cylinder resivor is still full, and I can't find any leaks.
What do you guys think? Is it time for a master cylinder? |
||
12-18-2001, 03:55 PM
|
|
|
Registered
|
Did this just happen or did it start when you did the flush?
It sounds more like air in the lines. A bad master tends to engage normally, but when you hold the brakes the peddle moves progressively to the floor. Did you do anything else to the brakes?
__________________
Clark Retired, I'm now posting under my real name Chuck Moreland Day Job - Elephant Racing Basic Transportation - '86 Cab - "Sparky", '77 Targa - "The Peaper" |
||
|
12-18-2001, 04:09 PM
|
|
|
Registered
Join Date: Oct 2000
Location: Nor-Cal
Posts: 4,403
|
Clark this just happened Sunday during a time trial at Thunder Hill. When I flushed the brakes a couple months ago, they worked great. But I guess I could have had an air bubble trapped in there, and all of the sudden it came loose. What do you think?
|
||
|
12-18-2001, 04:54 PM
|
|
|
Registered
|
I would bleed again. As for it being a bad master it is possible for a master to suck in air in the rear when the pedal is released. But that is unlikely. Clark perfectely decribed the way a master usually dies.
__________________
Never drive faster than your gaurdian angel can fly. 82 SC w/965S eng and G50 6:1 hp/w ratio 72 911t 2.6 twin plug and 72' 911t 57k orig 1 own miles 65/66 912 1 owner 76k orig 01' Aston Martin DB7 V12 Vantage Coupe 6spd |
||
|
12-18-2001, 05:01 PM
|
|
|
Registered
Join Date: Oct 2000
Location: Nor-Cal
Posts: 4,403
|
Thanks guys! Looks like I will be getting out the power bleeder Friday morning when I get off work.
|
||
|
12-18-2001, 05:10 PM
|
|
|
Senior Member
Join Date: Feb 2000
Location: Lacey, WA. USA
Posts: 25,310
|
Examine the brake line connections carefully. If the pedal suddenly goes closer to the floor, then fluid exited the system. You have a bad MC if the fluid exited past the seals, but there are plenty of other places to lose fluid.
If the pedal also feels spongy, then air is in the system. I'd agree that with a bad MC, the pedal goes gently but smoothly to the floor usually. Sometimes it does this, and if you stomp on it quickly, then the pedal will seem firm. either way, this is not your complaint.
__________________
Man of Carbon Fiber (stronger than steel) Mocha 1978 911SC. "Coco" |
||
|
12-18-2001, 08:14 PM
|
|
|
|
Registered
|
Thunderhill, sounds like you MIGHT have boiled the fluid. This same thing happened to me about 3 yrs. ago at sears pt. Changed it the next day and all was ok. But, i was only using dot 3.
__________________
72 911 Although it is done at the moment, it will never be finished. |
||
|
12-18-2001, 09:23 PM
|
|
1969 Porsche 911 2.7 
Tobluforu
