ZR-1 Net Registry Forums  

Go Back   ZR-1 Net Registry Forums > C4 ZR-1 > C4 ZR-1 Technical Postings

Reply
 
Thread Tools Display Modes
Old 04-16-2021   #31
Ccmano
 
Ccmano's Avatar
 
Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
Default Re: Rear brakes sticking lightly & Brake light comes on and off

When you look under the car just forward of the diff you'll see the cable for the emergency brake running cross the car. Follow the cable to the passenger side and you'll see a bracket that mounts it with a single bolt to the frame just ahead of the rear wheel. Undo that bolt completely and let the cable droop. This will take the emergency brake out of the equation. If the brakes still stick it either the master or something in the ABS system. Since you didn't get an ABS warning light its likely the master.
H
__________________
90'ZR-1 #1461 Red/Black
Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold
08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold
05 C6 Z51 Red/Black Sold
90'ZR-1 #1723 Black/Gray Sold but not forgotten
91' Z51 L98 White Vert. My First, you always remember your first. Sold.

Last edited by Ccmano; 04-16-2021 at 01:11 PM.
Ccmano is offline   Reply With Quote
Old 04-16-2021   #32
staminqia
 
staminqia's Avatar
 
Join Date: Dec 2020
Location: Pittsburgh
Posts: 145
Default Re: Rear brakes sticking lightly & Brake light comes on and off

Quote:
Originally Posted by 32valvesftw View Post
You could try loosening the brake line connection at the master cylinder for the rear, see if that losses them up, then do the same with the proportioning valve. That may give you an idea of where the issue is.
In a previous life I worked with subsea hydraulics, if this happened I would suspect a bad non-return valve, or bad actuator. We had much more instrumentation to tell us where to look though.
Ok this may be a bit too much but do you know which lines go to the rear? I dont have my service manuals yet. Also for the propostioning valve is it as simple as just unscrewing it from the front of the master cylinder? Will a bunch of fluid leak out when I do this?? This is a little out of my league.
staminqia is offline   Reply With Quote
Old 04-16-2021   #33
32valvesftw
 
Join Date: Jun 2015
Location: Texas
Posts: 530
Default Re: Rear brakes sticking lightly & Brake light comes on and off

I would have to trace the lines from the rear caliper towards the front.
Have a look at this:
https://www.corvetteactioncenter.com...rol/index.html
After reading through that I would pull the fuse that controls ABS and traction control and see if the wheels free up. The shop that said it was the hydraulic control unit, may not have been wrong he may have just used the wrong term.
32valvesftw is offline   Reply With Quote
Old 04-16-2021   #34
staminqia
 
staminqia's Avatar
 
Join Date: Dec 2020
Location: Pittsburgh
Posts: 145
Default Re: Rear brakes sticking lightly & Brake light comes on and off

Quote:
Originally Posted by 32valvesftw View Post
I would have to trace the lines from the rear caliper towards the front.
Have a look at this:
https://www.corvetteactioncenter.com...rol/index.html
After reading through that I would pull the fuse that controls ABS and traction control and see if the wheels free up. The shop that said it was the hydraulic control unit, may not have been wrong he may have just used the wrong term.
Ok now I have to find the right fuse. Wouldn't the car off release that pressure though if it was ABS?
staminqia is offline   Reply With Quote
Old 04-16-2021   #35
Ccmano
 
Ccmano's Avatar
 
Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
Default Re: Rear brakes sticking lightly & Brake light comes on and off

Forgot to ask, are both rear calipers locked or just one?
H
__________________
90'ZR-1 #1461 Red/Black
Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold
08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold
05 C6 Z51 Red/Black Sold
90'ZR-1 #1723 Black/Gray Sold but not forgotten
91' Z51 L98 White Vert. My First, you always remember your first. Sold.
Ccmano is offline   Reply With Quote
Old 04-16-2021   #36
staminqia
 
staminqia's Avatar
 
Join Date: Dec 2020
Location: Pittsburgh
Posts: 145
Default Re: Rear brakes sticking lightly & Brake light comes on and off

Quote:
Originally Posted by Ccmano View Post
Forgot to ask, are both rear calipers locked or just one?
H
they are both locked up.
staminqia is offline   Reply With Quote
Old 04-17-2021   #37
staminqia
 
staminqia's Avatar
 
Join Date: Dec 2020
Location: Pittsburgh
Posts: 145
Default Re: Rear brakes sticking lightly & Brake light comes on and off

Well, I decided today to flush the old brake fluid and bleed all the lines. I did it. All new clean fluid. Then I put tires on started it and viola no light!. Took it for a spin and no sticking at a stop and no light. I hope this was the issue and it doesn't come back but for now I'm back to normal. Moral of the story here is when you get a 30 year old car flush the fluids first. That was the issue.

Thanks for everyone's help. I'll keep you all posted if it come back.
staminqia is offline   Reply With Quote
Old 04-17-2021   #38
Ccmano
 
Ccmano's Avatar
 
Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
Default Re: Rear brakes sticking lightly & Brake light comes on and off

Quote:
Originally Posted by staminqia View Post
Well, I decided today to flush the old brake fluid and bleed all the lines. I did it. All new clean fluid. Then I put tires on started it and viola no light!. Took it for a spin and no sticking at a stop and no light. I hope this was the issue and it doesn't come back but for now I'm back to normal. Moral of the story here is when you get a 30 year old car flush the fluids first. That was the issue.

Thanks for everyone's help. I'll keep you all posted if it come back.
Glad you got it. Surprised that worked, but hey it's fixed!
H
__________________
90'ZR-1 #1461 Red/Black
Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold
08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold
05 C6 Z51 Red/Black Sold
90'ZR-1 #1723 Black/Gray Sold but not forgotten
91' Z51 L98 White Vert. My First, you always remember your first. Sold.
Ccmano is offline   Reply With Quote
Old 04-17-2021   #39
32valvesftw
 
Join Date: Jun 2015
Location: Texas
Posts: 530
Default Re: Rear brakes sticking lightly & Brake light comes on and off

Good work! There was probably sludge fouling up something.
32valvesftw is offline   Reply With Quote
Old 04-17-2021   #40
staminqia
 
staminqia's Avatar
 
Join Date: Dec 2020
Location: Pittsburgh
Posts: 145
Default Re: Rear brakes sticking lightly & Brake light comes on and off

Yes it was really dark and sludgy. Let's hope it doesn't come back. So if someone has this same problem bleed the system FIRST.

THANK YOU GUYS!
staminqia is offline   Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 06:44 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright ZR-1 Net Registry 2020