Soft pedal after panic stop
Thread Starter
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
Soft pedal after panic stop
About a week ago some blue-hair in a Gran Marquis tried to kill me but luckily the ABS + Corvette brakes won out. The problem is after that stop I seem to have a pretty soft brake pedal and decreased braking ability. Didn't notice any loss of fluid and the car will stop eventually so I don't think I blew any lines/hoses (Done that before - not fun).
Any ideas on what I broke?
As an aside, Corvettes need louder horns or loud speakers to shout obscenities not the wussy *meep* horns they have now
Thanks all!
Dale
Any ideas on what I broke?
As an aside, Corvettes need louder horns or loud speakers to shout obscenities not the wussy *meep* horns they have now
Thanks all!
Dale
Burning Brakes
Joined: Aug 2001
Posts: 1,238
Likes: 0
From: walled lake MI
if you stopped from a pretty high speed, i suspect you boiled the brake fluid. cheap thing you can do is flush out the old fluid and put in some new. it certainly will not hurt. once the fluid boils, it just gets even worse.
brake fluid absorbs water over time and the moisture lowers its boiling point. do a couple of panic stops at this point - voila! brake fade.
as a precaution i bleed my brakes every two months or so to spit the heat cycled fluid out of the calipers.
brake fluid absorbs water over time and the moisture lowers its boiling point. do a couple of panic stops at this point - voila! brake fade.
as a precaution i bleed my brakes every two months or so to spit the heat cycled fluid out of the calipers.
Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
Possible that you may have weakened the seals in the master cylinder so that it's not pumping the fluid like it should. However it usually is more serious than your description but without trying the pedal myself that's my best guess. Might want to consider a new m.c.
Thread Starter
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
The stop was only from about 55-0 maybe less as I just came thru a small construction area. My brake fluid is maybe 1.5 yrs old - not good but I don't race the car so it should be good enough for a quickie stop once and awhile.
I was thinking I might have a MC problem but didn't want to start throwing parts at with out input. Might be a good excuse for the bias spring upgrade
To better describe the pedal - It is kinda like the brakes don't grab until about 1/3 to half travel. I doubt I would survive another panic stop. I had to push the pedal to about 60% just for a kinda short off ramp. In fact, when I get home from work this morning the Vette is getting parked until I fix this - it is not safe.
I was thinking I might have a MC problem but didn't want to start throwing parts at with out input. Might be a good excuse for the bias spring upgrade
To better describe the pedal - It is kinda like the brakes don't grab until about 1/3 to half travel. I doubt I would survive another panic stop. I had to push the pedal to about 60% just for a kinda short off ramp. In fact, when I get home from work this morning the Vette is getting parked until I fix this - it is not safe.
Racer
Joined: Jun 2002
Posts: 428
Likes: 0
From: Dallas Tx
I agree with the advice.
If you have not changed brake fluid in over a year, I'd do that first.
It may fix the problem, and you probably needed to do it anyway.
As an aside, I've been very happy with PFC Z-rated brake pads. Work well when hot, and still have nice "grab" when cold (for the around town LOL in the Grand Marquis).
If you have not changed brake fluid in over a year, I'd do that first.
It may fix the problem, and you probably needed to do it anyway.
As an aside, I've been very happy with PFC Z-rated brake pads. Work well when hot, and still have nice "grab" when cold (for the around town LOL in the Grand Marquis).
Thread Starter
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
Thanks for the advice all! 
I'll stop by AutoZone tomorrow and order a reman master cylinder - Lifetime warranty and I have had good luck with their reman calipers so I'll give it a try. I also plan on ordering a Bias spring and speed bleeders from VBP as long as everything is apart. Gotta turn a repair into a mod somehow, right
I doubt just the brake fluid would cause this problem - at least not directly. I have had cars with 100K miles on the same old, cruddy, black fluid and the brakes were fine (not a bright idea I know). Although, living in salt country (Northern WI/UP) usually forces a bleed about 120K or so due to lines rusting out.
BTW: The problem is getting worse. On the way home this morning, it took nearly 60% pedal to keep the car held on a small hill - not good.
Thanks again!
Dale
Edit:
I use PF Carbon Met. from AZ but I need to get something else (Hawk, maybe). I am on my second set in under 20K miles due to them glazing and not stopping the car. The Z-Rated are probably better but these pads have left a sour taste (Not literally) for PF.
I'll stop by AutoZone tomorrow and order a reman master cylinder - Lifetime warranty and I have had good luck with their reman calipers so I'll give it a try. I also plan on ordering a Bias spring and speed bleeders from VBP as long as everything is apart. Gotta turn a repair into a mod somehow, right
I doubt just the brake fluid would cause this problem - at least not directly. I have had cars with 100K miles on the same old, cruddy, black fluid and the brakes were fine (not a bright idea I know). Although, living in salt country (Northern WI/UP) usually forces a bleed about 120K or so due to lines rusting out.
BTW: The problem is getting worse. On the way home this morning, it took nearly 60% pedal to keep the car held on a small hill - not good.
Thanks again!
Dale
Edit:
I use PF Carbon Met. from AZ but I need to get something else (Hawk, maybe). I am on my second set in under 20K miles due to them glazing and not stopping the car. The Z-Rated are probably better but these pads have left a sour taste (Not literally) for PF.
Last edited by Dale1990; Dec 9, 2004 at 11:48 PM.
Burning Brakes
Joined: Aug 2001
Posts: 1,238
Likes: 0
From: walled lake MI
a friendly warning - quite a few forum members have had bad luck with remanned master cylinders.
i used to have the carbon metallics and recently switched to the Z rated. it is a world of difference although it still isn't great when it is cold. the Hawks or the Greenstuff will provide better performance at the sacrifice of more dusting.
i used to have the carbon metallics and recently switched to the Z rated. it is a world of difference although it still isn't great when it is cold. the Hawks or the Greenstuff will provide better performance at the sacrifice of more dusting.
Thread Starter
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
I appreciate the warning. I haven't been burned yet but there is always a first time. I used to work at AZ and we did not seem to get many returns on the brake stuff except for people not ordering the right parts. Electrical is another story...
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