Inconsistent Brake Pressure
Thread Starter
Race Director
Joined: Dec 2005
Posts: 13,515
Likes: 12
From: Fisher, IL
Inconsistent Brake Pressure
I changed out a caliper a month ago along with a lot of the lines in the wheel well area on my 69.
I used the Motive power bleeder and it worked great.
But it seems like every time I get in my car the brake pressure is different. Sometimes it's almost nonexistent(dangerous) while other times it is perfectly fine.
I don't know if i need to bleed the system some more due to maybe an air bubble in it or if something else is causing this....
I used the Motive power bleeder and it worked great.
But it seems like every time I get in my car the brake pressure is different. Sometimes it's almost nonexistent(dangerous) while other times it is perfectly fine.
I don't know if i need to bleed the system some more due to maybe an air bubble in it or if something else is causing this....
Thread Starter
Race Director
Joined: Dec 2005
Posts: 13,515
Likes: 12
From: Fisher, IL
Yeah I think I'll bleed the system tomorrow after work and see if it helps any.
It's just not very safe driving with minimal brake some of the time, I can get by but it just takes that one quick stop scenario and I'd be boned.
It's just not very safe driving with minimal brake some of the time, I can get by but it just takes that one quick stop scenario and I'd be boned.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Try sitting with the engine running and putting your foot on the brake like your stopped at a light and hold pressure, now lighten the pressure on the pedal slightly, then push down a little more, lighten , push , lighten ,push. If you can sneak the pedal to the floor the master is bad.
Thread Starter
Race Director
Joined: Dec 2005
Posts: 13,515
Likes: 12
From: Fisher, IL
I hope bleeding does help but inconsistency in my experience has been the master cylinder.
Try sitting with the engine running and putting your foot on the brake like your stopped at a light and hold pressure, now lighten the pressure on the pedal slightly, then push down a little more, lighten , push , lighten ,push. If you can sneak the pedal to the floor the master is bad.
Try sitting with the engine running and putting your foot on the brake like your stopped at a light and hold pressure, now lighten the pressure on the pedal slightly, then push down a little more, lighten , push , lighten ,push. If you can sneak the pedal to the floor the master is bad.
Is that the case? Could there still be air in the master even if I can get fluids at the calipers?
And what on a master cylinder usually goes bad?
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
I don't want to admit it but I'm pretty sure I ran the master cylinder dry in one cell when i was changing out some of the lines. I know everyone has to bench bleed if that happens but when i got everything to bleed at the calipers i figured i was okay.
Is that the case? Could there still be air in the master even if I can get fluids at the calipers?
And what on a master cylinder usually goes bad?
Is that the case? Could there still be air in the master even if I can get fluids at the calipers?
And what on a master cylinder usually goes bad?
What I usually find that goes bad is the seals inside, no outside leak,the seals allow fluid to slip past them. (If you push really hard the seals hold but when you push easy the piston and seals just slip through the fluid.)
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Until I went Hydro Boost on my '72 with vacuum booster, and the same thing on a motor home not long ago.....the pedal feel was all over the joint, vette had been HB for some 6? years now, and solid/consistent but until then I always had that bad feeling, and soft pedal....
in both cases, my swap to HB was done on a A-B basis, meaning I did not disturb the master cylinder/lines......been proven twice now...
on two greatly different vehicles...
in both cases, my swap to HB was done on a A-B basis, meaning I did not disturb the master cylinder/lines......been proven twice now...
on two greatly different vehicles...
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Until I went Hydro Boost on my '72 with vacuum booster, and the same thing on a motor home not long ago.....the pedal feel was all over the joint, vette had been HB for some 6? years now, and solid/consistent but until then I always had that bad feeling, and soft pedal....
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Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
Until I went Hydro Boost on my '72 with vacuum booster, and the same thing on a motor home not long ago.....the pedal feel was all over the joint, vette had been HB for some 6? years now, and solid/consistent but until then I always had that bad feeling, and soft pedal....
in both cases, my swap to HB was done on a A-B basis, meaning I did not disturb the master cylinder/lines......been proven twice now...
on two greatly different vehicles...
in both cases, my swap to HB was done on a A-B basis, meaning I did not disturb the master cylinder/lines......been proven twice now...
on two greatly different vehicles...
There are 2 types of C3 brake people, those who have Hydro Boost, and those who have never tried Hydro Boost
$300, a little time ..... and an amazing upgrade!!
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
but outta 50 years of driving cars with vacuum sucking, and these two with the HB conversion....gimme the hydraulics, they don't suck....
Melting Slicks
Joined: Mar 2007
Posts: 2,520
Likes: 11
From: Hinckley OH
Le Mans Master
Joined: Apr 2001
Posts: 5,000
Likes: 1
From: Minneapolis, Mn USA
I had my brother drive my Vette with HB, and he is now converting his old Monte Carlo over to HB. Another convert sold!!
He says the only thing even close to it are the electro-mechanical brakes on the Mercedes cars, which he works on daily (mechanic) for electro-mechanical problems.
B.
He says the only thing even close to it are the electro-mechanical brakes on the Mercedes cars, which he works on daily (mechanic) for electro-mechanical problems.
B.
