Brake bleeding question
Thread Starter
Burning Brakes
Joined: Nov 2006
Posts: 793
Likes: 1
Brake bleeding question
So I just got done installing my newly painted calipers and bled out the brake system today. However something just didn't seem right and after reading old posts on how to bleed the brakes I think I might have screwed something up. When I removed the calipers I left the brake lines hang and drained all of the fluid. When I went to put the calipers back on and bleed the brakes I noticed the brake reservoir was totally drained. Is this bad? I just read something that said if this happens I need to have the dealership bleed my abs system. I filled it up and bled the brakes as normal but now im paranoid I have air in my abs system.
Former Vendor
Joined: Aug 2005
Posts: 5,774
Likes: 0
From: Loganville GA
If they aren't soft, you are fine. If they are spongy, then you may need to have the dealer bleed them. One other thing to check first though, if they are spongy, is whether or not the rears are on the correct sides. The bleed screws should be above the fluid lines, and its a common mistake to put them on backwards.
Safety Car
Joined: Aug 2007
Posts: 4,836
Likes: 9
From: Rushsylvania Ohio
Also, the C6 brake system is not like most cars in that the brake system is not split front and rear like most vehicles, but rather diagonal. If a brake system failure happens, this helps to insure at least one front and one rear brake will still work.
To properly bleed the brakes, the sequence is:
RR
LF
LR
RF
Not saying this will help you, but if you are worried, you might try bleeding again using this sequence. Also, even if your reservoir was empty, if you did not pump the brakes with it empty, you most likely did not get air into the system from the reservoir.
To properly bleed the brakes, the sequence is:
RR
LF
LR
RF
Not saying this will help you, but if you are worried, you might try bleeding again using this sequence. Also, even if your reservoir was empty, if you did not pump the brakes with it empty, you most likely did not get air into the system from the reservoir.
Thread Starter
Burning Brakes
Joined: Nov 2006
Posts: 793
Likes: 1
I didn't pump the brakes when the reservoir was empty. I know I did a good job of bleeding them, I was just concerned about the ABS circuit. How do I know if I got air in it?
Also, the C6 brake system is not like most cars in that the brake system is not split front and rear like most vehicles, but rather diagonal. If a brake system failure happens, this helps to insure at least one front and one rear brake will still work.
To properly bleed the brakes, the sequence is:
RR
LF
LR
RF
Not saying this will help you, but if you are worried, you might try bleeding again using this sequence. Also, even if your reservoir was empty, if you did not pump the brakes with it empty, you most likely did not get air into the system from the reservoir.
To properly bleed the brakes, the sequence is:
RR
LF
LR
RF
Not saying this will help you, but if you are worried, you might try bleeding again using this sequence. Also, even if your reservoir was empty, if you did not pump the brakes with it empty, you most likely did not get air into the system from the reservoir.
Tech Contributor
Joined: Oct 1999
Posts: 41,026
Likes: 9,777
From: Charlotte, NC (formerly Endicott, NY)
As Corvette Pilot said if the pedal is hard you don't have a problem. However, you state that something isn't just right which leaves the question of what isn't just right?
By letting the reservoir go dry you probably got air into the system upstream of the BPMV and the only way to completely bleed it is to have the service department do an abs automated bleed. Here are the directions from the Service Manual for doing Manual Bleeding:
Hydraulic Brake System Bleeding Manual
Caution
Refer to Brake Fluid Irritant Caution in Cautions and Notices.
Notice
When adding fluid to the brake master cylinder reservoir, use only Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.
Notice
Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Cautions and Notices.
By letting the reservoir go dry you probably got air into the system upstream of the BPMV and the only way to completely bleed it is to have the service department do an abs automated bleed. Here are the directions from the Service Manual for doing Manual Bleeding:
Hydraulic Brake System Bleeding Manual
Caution
Refer to Brake Fluid Irritant Caution in Cautions and Notices.
Notice
When adding fluid to the brake master cylinder reservoir, use only Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.
Notice
Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Cautions and Notices.
- Place a clean shop cloth beneath the brake master cylinder to prevent brake fluid spills.
- With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake pedal effort increases significantly, in order to deplete the brake booster power reserve.
- If you have performed a brake master cylinder bench bleeding on this vehicle, or if you disconnected the brake pipes from the master cylinder, you must perform the following steps:
- Ensure that the brake master cylinder reservoir is full to the maximum-fill level. If necessary, add Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. If removal of the reservoir cap and diaphragm is necessary, clean the outside of the reservoir on and around the cap prior to removal.
- With the rear brake pipe installed securely to the master cylinder, loosen and separate the front brake pipe from the front port of the brake master cylinder.
- Allow a small amount of brake fluid to gravity bleed from the open port of the master cylinder.
- Reconnect the brake pipe to the master cylinder port and tighten securely.
- Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal.
- Loosen the same brake pipe to purge air from the open port of the master cylinder.
- Tighten the brake pipe, then have the assistant slowly release the brake pedal.
- Wait 15 seconds, then repeat steps 3.3-3.7 until all air is purged from the same port of the master cylinder.
- With the front brake pipe installed securely to the master cylinder, after all air has been purged from the front port of the master cylinder, loosen and separate the rear brake pipe from the master cylinder, then repeat steps 3.3-3.8.
- After completing the final master cylinder port bleeding procedure, ensure that both of the brake pipe-to-master cylinder fittings are properly tightened.
- Fill the brake master cylinder reservoir with Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. Ensure that the brake master cylinder reservoir remains at least half-full during this bleeding procedure. Add fluid as needed to maintain the proper level. Clean the outside of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm.
- Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic circuit bleeder valve.
- Install a transparent hose over the end of the bleeder valve.
- Submerge the open end of the transparent hose into a transparent container partially filled with Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
- Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal. <
- Loosen the bleeder valve to purge air from the wheel hydraulic circuit.
- Tighten the bleeder valve, then have the assistant slowly release the brake pedal.
- Wait 15 seconds, then repeat steps 8-10 until all air is purged from the same wheel hydraulic circuit.
- With the right rear wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the right rear hydraulic circuit, install a proper box-end wrench onto the LEFT FRONT wheel hydraulic circuit bleeder valve.
- Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.
- With the left front wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the left front hydraulic circuit, install a proper box-end wrench onto the LEFT REAR wheel hydraulic circuit bleeder valve.
- Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.
- With the left rear wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the left rear hydraulic circuit, install a proper box-end wrench onto the RIGHT FRONT wheel hydraulic circuit bleeder valve.
- Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.
- After completing the final wheel hydraulic circuit bleeding procedure, ensure that each of the 4 wheel hydraulic circuit bleeder valves are properly tightened.
- Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
- Slowly depress and release the brake pedal. Observe the feel of the brake pedal.
Important
If it is determined that air was induced into the system upstream of the ABS modulator prior to servicing, the ABS Automated Bleed Procedure must be performed.
If the brake pedal feels spongy, repeat the bleeding procedure again. If the brake pedal still feels spongy after repeating the bleeding procedure, perform the following steps:- Inspect the brake system for external leaks. Refer to Brake System External Leak Inspection .
- Pressure bleed the hydraulic brake system in order to purge any air that may still be trapped in the system.
- Turn the ignition key ON, with the engine OFF. Check to see if the brake system warning lamp remains illuminated.
Important
DO NOT allow the vehicle to be driven until it is diagnosed and repaired. - If the brake system warning lamp remains illuminated, refer to Symptoms - Hydraulic Brakes .
Last edited by Bill Dearborn; Feb 20, 2010 at 06:12 PM.
Thread Starter
Burning Brakes
Joined: Nov 2006
Posts: 793
Likes: 1
Its not that I think something is not right, im just concearned beacuse I have read posts saying the if you let the reservoir drain then I will introduce air into sections that will not bleed out from just bleeding the calipers. A "spongy" brake pedal and a"firm" brake pedal are very subjective so im having a hard time knowing if something is wrong. I just purchased the car not that long ago so I don't have a very good before and after comparison.
Tech Contributor
Joined: Oct 1999
Posts: 41,026
Likes: 9,777
From: Charlotte, NC (formerly Endicott, NY)
I would use your own judgement on how it feels. If it doesn't feel right it probably isn't. The brake pedal shouldn't be instantly hard when you step on it. There should be a little drop before you hit resistance. When it hits that point and it feels spongy then you have a problem.
If you take it to the dealer tell them what happened. That way they have a better chance of helping you.
Bill
If you take it to the dealer tell them what happened. That way they have a better chance of helping you.
Bill
Last edited by Bill Dearborn; Feb 20, 2010 at 08:09 PM.
