Brakes? I have none. 1990 Corvette
10-30-2012, 11:08 PM
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Brakes? I have none. 1990 Corvette
So I am finally at a point where I think I can take a test drive.
But What?
I have no brakes.
During the "put everything back together phase", I took the front Brake calipers off, cleaned em, and topped em with fresh paint.
The Calipers were off the car for at least a week. So I put back on a few weeks ago and they sat.
Now I have no brakes. Normally I would add fluid and pump. Follow that up with bleeding the air that leaked in.
But when I tried to bleed, nothing comes out. There is no pressure.
I've read a few other posts and stickies.
Do I need to bleed the master cylinder? I did let the fluid get too low.
I found this in the Stickies-
Information
Most instruction manuals indicate that you should place the
Master Cylinder in a vise and then use a dowel rod to press on the plunger
to bleed the air out of the Master Cylinder. I found an easier way is to
bleed the air out of the system
backwards.
Supplies:
Fittings for bleeding hose (usually
included with new Master Cylinder)
Bleeding Hose (usually included with
new Master Cylinder)
New pump oil can (New to make sure that it is not
contaminated)
Brake Fluid.
Once you are ready to bleed the air
from the master cylinder screw the fittings into the appropriate holes,
and attach the bleeder hose to the fittings. During the next process you
will drip brake fluid so use a pan to catch what is lost.
Fill the
reservoir with brake fluid. Through this process, and until you get the
brake lines attached to the New Master Cylinder make sure that the
reservoir level does not fall below the minimum level.
Place the
tip of the pump oilcan in the end of one of the brake bleeder hoses and
begin pumping brake fluid into the system backward. Continue until you do
not see any more air bubbles in the reservoir.
Once you finish with
the one line switch to the other and repeat the previous step.
Once
you have the air removed from both the front and rear brake line
connecting points, remove the fittings and bleeding
tubes.
Reinstall the Master Cylinder on the car.
I also read about letting gravity bleed them-
So the car is outside, on jacks, its been 5+ hours and barely a teaspoon has dripped out.
Before that I hooked up the Vacuum pump. Pump, pump, pump and nothing comes out.
So whats the secret?
But What?
I have no brakes.
During the "put everything back together phase", I took the front Brake calipers off, cleaned em, and topped em with fresh paint.
The Calipers were off the car for at least a week. So I put back on a few weeks ago and they sat.
Now I have no brakes. Normally I would add fluid and pump. Follow that up with bleeding the air that leaked in.
But when I tried to bleed, nothing comes out. There is no pressure.
I've read a few other posts and stickies.
Do I need to bleed the master cylinder? I did let the fluid get too low.
I found this in the Stickies-
Information
Most instruction manuals indicate that you should place the
Master Cylinder in a vise and then use a dowel rod to press on the plunger
to bleed the air out of the Master Cylinder. I found an easier way is to
bleed the air out of the system
backwards.
Supplies:
Fittings for bleeding hose (usually
included with new Master Cylinder)
Bleeding Hose (usually included with
new Master Cylinder)
New pump oil can (New to make sure that it is not
contaminated)
Brake Fluid.
Once you are ready to bleed the air
from the master cylinder screw the fittings into the appropriate holes,
and attach the bleeder hose to the fittings. During the next process you
will drip brake fluid so use a pan to catch what is lost.
Fill the
reservoir with brake fluid. Through this process, and until you get the
brake lines attached to the New Master Cylinder make sure that the
reservoir level does not fall below the minimum level.
Place the
tip of the pump oilcan in the end of one of the brake bleeder hoses and
begin pumping brake fluid into the system backward. Continue until you do
not see any more air bubbles in the reservoir.
Once you finish with
the one line switch to the other and repeat the previous step.
Once
you have the air removed from both the front and rear brake line
connecting points, remove the fittings and bleeding
tubes.
Reinstall the Master Cylinder on the car.
I also read about letting gravity bleed them-
So the car is outside, on jacks, its been 5+ hours and barely a teaspoon has dripped out.
Before that I hooked up the Vacuum pump. Pump, pump, pump and nothing comes out.
So whats the secret?
10-31-2012, 01:32 AM
#2
Le Mans Master
You need to bench bleed the master cylinder in a vise or risk paint removal on anything the brake fluid comes in contact with.
After you bleed the master, install it on the car and hook up the lines. Fill the reservoir.
Have an assistant pump the pedal twice, and hold the pedal to the floor....then start with the right rear, then left rear, then right front then L.F.
after the pedal is depressed and held to the foor, open the first bleeder, the lock it off quick.
Do it a couple times, then progress aound the car.
Make sure the master cylinder does not get dry, and the ports in the master that are visible through the fluid are not uncovered. Keep adding fluid to the reservoir.
Then go back to the first bleeder, and this time, same thing, but you will start to get some fluid pressure out of the rear caliper.
Keep that in mind as you move to the next caliper in sequence.
It may take 3 or 4 times around the car to get the pressure you desire.
Each time though, the assistant must not release the pedal until you have locked off the bleeder.
Once you have established pressure, you need to perform a panic stop to activate the ABS. THen you need to rebleed the rears again.
What I do when removing the master cylinder lines is to get a couple of wooden pencils, and sharpen them, and break the lead off. then with the lead broken off (it won't break off in the line), insert the sharpened end in to the line. the pencil will only go in so far, and wedge itself in the flare. The wood of the pencil swells with the fluid, and will stop any fluid loss when you take the calipers off.
(Kind of like sticking a drinking straw in a liquid, and putting your finger over the end.)
THen when you bleed, the lines are mostly full, and you do not have to start all over again.
After you bleed the master, install it on the car and hook up the lines. Fill the reservoir.
Have an assistant pump the pedal twice, and hold the pedal to the floor....then start with the right rear, then left rear, then right front then L.F.
after the pedal is depressed and held to the foor, open the first bleeder, the lock it off quick.
Do it a couple times, then progress aound the car.
Make sure the master cylinder does not get dry, and the ports in the master that are visible through the fluid are not uncovered. Keep adding fluid to the reservoir.
Then go back to the first bleeder, and this time, same thing, but you will start to get some fluid pressure out of the rear caliper.
Keep that in mind as you move to the next caliper in sequence.
It may take 3 or 4 times around the car to get the pressure you desire.
Each time though, the assistant must not release the pedal until you have locked off the bleeder.
Once you have established pressure, you need to perform a panic stop to activate the ABS. THen you need to rebleed the rears again.
What I do when removing the master cylinder lines is to get a couple of wooden pencils, and sharpen them, and break the lead off. then with the lead broken off (it won't break off in the line), insert the sharpened end in to the line. the pencil will only go in so far, and wedge itself in the flare. The wood of the pencil swells with the fluid, and will stop any fluid loss when you take the calipers off.
(Kind of like sticking a drinking straw in a liquid, and putting your finger over the end.)
THen when you bleed, the lines are mostly full, and you do not have to start all over again.
Last edited by coupeguy2001; 10-31-2012 at 01:41 AM.
10-31-2012, 03:04 AM
#3
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You need to bench bleed the master cylinder in a vise or risk paint removal on anything the brake fluid comes in contact with.
After you bleed the master, install it on the car and hook up the lines. Fill the reservoir.
Have an assistant pump the pedal twice, and hold the pedal to the floor....then start with the right rear, then left rear, then right front then L.F.
after the pedal is depressed and held to the foor, open the first bleeder, the lock it off quick.
Do it a couple times, then progress aound the car.
Make sure the master cylinder does not get dry, and the ports in the master that are visible through the fluid are not uncovered. Keep adding fluid to the reservoir.
Then go back to the first bleeder, and this time, same thing, but you will start to get some fluid pressure out of the rear caliper.
Keep that in mind as you move to the next caliper in sequence.
It may take 3 or 4 times around the car to get the pressure you desire.
Each time though, the assistant must not release the pedal until you have locked off the bleeder.
Once you have established pressure, you need to perform a panic stop to activate the ABS. THen you need to rebleed the rears again.
What I do when removing the master cylinder lines is to get a couple of wooden pencils, and sharpen them, and break the lead off. then with the lead broken off (it won't break off in the line), insert the sharpened end in to the line. the pencil will only go in so far, and wedge itself in the flare. The wood of the pencil swells with the fluid, and will stop any fluid loss when you take the calipers off.
(Kind of like sticking a drinking straw in a liquid, and putting your finger over the end.)
THen when you bleed, the lines are mostly full, and you do not have to start all over again.
After you bleed the master, install it on the car and hook up the lines. Fill the reservoir.
Have an assistant pump the pedal twice, and hold the pedal to the floor....then start with the right rear, then left rear, then right front then L.F.
after the pedal is depressed and held to the foor, open the first bleeder, the lock it off quick.
Do it a couple times, then progress aound the car.
Make sure the master cylinder does not get dry, and the ports in the master that are visible through the fluid are not uncovered. Keep adding fluid to the reservoir.
Then go back to the first bleeder, and this time, same thing, but you will start to get some fluid pressure out of the rear caliper.
Keep that in mind as you move to the next caliper in sequence.
It may take 3 or 4 times around the car to get the pressure you desire.
Each time though, the assistant must not release the pedal until you have locked off the bleeder.
Once you have established pressure, you need to perform a panic stop to activate the ABS. THen you need to rebleed the rears again.
What I do when removing the master cylinder lines is to get a couple of wooden pencils, and sharpen them, and break the lead off. then with the lead broken off (it won't break off in the line), insert the sharpened end in to the line. the pencil will only go in so far, and wedge itself in the flare. The wood of the pencil swells with the fluid, and will stop any fluid loss when you take the calipers off.
(Kind of like sticking a drinking straw in a liquid, and putting your finger over the end.)
THen when you bleed, the lines are mostly full, and you do not have to start all over again.
Taking this Master Cylinder off better not be a PITA.
So the gravity technique is a waste of time?
(Doesn't seem to be working anyway)
10-31-2012, 05:48 PM
#5
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So I tried to bleed the master cylinder. On a bench.
The piston got stuck inside. I took off the ring and got the piston out.
There isn't any spring inside. The manual shows a spring. Oh well.
As I don't know the history of the car, I must assume that it was swapped out or something to that effect.
I ordered a rebuilt one from Napa. $77 with a core.
But the rebuilt one doesn't come with the reservoirs. I now need to figure how to get them off and on without damage.
The piston got stuck inside. I took off the ring and got the piston out.
There isn't any spring inside. The manual shows a spring. Oh well.
As I don't know the history of the car, I must assume that it was swapped out or something to that effect.
I ordered a rebuilt one from Napa. $77 with a core.
But the rebuilt one doesn't come with the reservoirs. I now need to figure how to get them off and on without damage.
11-01-2012, 02:09 AM
#8
Le Mans Master
The stuck piston is why your gravity method did not work. the piston covers the hole in the master cyl. body if the spring does not return the piston to the "at rest" position.
If you had a spring in it, and the piston returned to "ready" position, the fluid would run down to the calipers.
Since you are using a rebuilt, put it in a vise, and push on the piston. it should return. If it does, then add the reservoirs.
You can still buy the reservoirs at Eckler's if you ruin them getting them off.
If you had a spring in it, and the piston returned to "ready" position, the fluid would run down to the calipers.
Since you are using a rebuilt, put it in a vise, and push on the piston. it should return. If it does, then add the reservoirs.
You can still buy the reservoirs at Eckler's if you ruin them getting them off.
Last edited by coupeguy2001; 11-01-2012 at 03:22 PM.
11-01-2012, 06:00 PM
#9
Burning Brakes
These guys are steering you in the right direction.
I would suggest, while you are at it, that you replace the old brake line hoses. After all, they are 23 years old and will fail at some point. Replace them with stock-looking rubber or stainless braided Teflon hoses (my choice). I also replaced the bleed fittings with "SpeedBleeders". They work great. Sure does make bleeding my brakes a whole lot easier. I have completely replaced the old brake fluid with new fluid twice, now. It was a piece of cake.
I would suggest, while you are at it, that you replace the old brake line hoses. After all, they are 23 years old and will fail at some point. Replace them with stock-looking rubber or stainless braided Teflon hoses (my choice). I also replaced the bleed fittings with "SpeedBleeders". They work great. Sure does make bleeding my brakes a whole lot easier. I have completely replaced the old brake fluid with new fluid twice, now. It was a piece of cake.
11-02-2012, 02:00 AM
#10
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Put the Master Cylinder on.
Bled the front breaks, all new fluid.
There is something going on with the back brakes. Need to get it up on jack stands to take a look.
Bled the front breaks, all new fluid.
There is something going on with the back brakes. Need to get it up on jack stands to take a look.
11-03-2012, 02:11 AM
#12
yep!
I was wondering if anyone remeobered the ABS !
thats a whole other brake system in itself that has lots to do with fluid and what gets fluid/when and how much.
The FSM has the process for bleeding ABS.
Or, the short cut is just as described...bleed as well as you can, roll the car running and stomp the pedal a couple times. Do the roll & stomp a cpl times. This will throw another cycle of the abs pump that helps move fluid where you can't make it move. Each time you roll, the ABS will self test and cycle the pump. Pound the pedal and that forces an ABS pump & dump cycle. There is close to a mile of additional tubing and other stuff in the ABS system and pump hidden behind the seat. Lots of places for air to hide..
That should help chase any remaining air toward the calipers. Go find a set of self bleeders...screws with check valves so you can open them to let fluid squirt out but they won't let air back in.
I was wondering if anyone remeobered the ABS !
thats a whole other brake system in itself that has lots to do with fluid and what gets fluid/when and how much.
The FSM has the process for bleeding ABS.
Or, the short cut is just as described...bleed as well as you can, roll the car running and stomp the pedal a couple times. Do the roll & stomp a cpl times. This will throw another cycle of the abs pump that helps move fluid where you can't make it move. Each time you roll, the ABS will self test and cycle the pump. Pound the pedal and that forces an ABS pump & dump cycle. There is close to a mile of additional tubing and other stuff in the ABS system and pump hidden behind the seat. Lots of places for air to hide..
That should help chase any remaining air toward the calipers. Go find a set of self bleeders...screws with check valves so you can open them to let fluid squirt out but they won't let air back in.
11-03-2012, 03:35 AM
#13
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I'm on it.
I plan on taking the wheels off tomorrow. Honestly- It kinda feels like the parking brake is stuck on. I'll take some pictures if I find anything strange.
On top of the vette, I'll be doing my other sons brakes. And Early voting because I'm forced to travel on the first Tuesday following the first Monday in November.
I plan on taking the wheels off tomorrow. Honestly- It kinda feels like the parking brake is stuck on. I'll take some pictures if I find anything strange.
On top of the vette, I'll be doing my other sons brakes. And Early voting because I'm forced to travel on the first Tuesday following the first Monday in November.
11-11-2012, 07:32 PM
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I've had the wheels off so often the past week I feel like I am on a pit crew.
I've replaced the master cylinder. I bench bled it as perfectly as can be done.
I bled the front as they were the ones that were originally taken off allowing air in.
Then I bled all 4. Passenger Rear/Driver Rear/Passenger Front/Driver Front.
I am running Clear brake fluid out of all four and I see no air coming out.
I also took the cover off the parking brake mechanism. It was all gummed up in there. Sprayed with PB Blaster and it freed up the mechanism. Parking brakes now work correctly, instead of being stuck on.
Issue: I need to pump brakes three times to get any reaction- At 20 MPH or so, the first pump goes to the floor, it tightens the brakes the provides minimal stopping power.
Second pump goes half way, brakes starting to react.
Third pump, brakes feel hard, (as they should) and the brakes react like they should.
Could it be:
1. I took the front calipers off. Did I put them on correctly? The bleed valve is on the bottom. I'm wondering if I got driver and passenger side swapped. Don't even know if its possible.
2. There is an adjustment bolt behind the master cylinder. Does that need to be adjusted?
Any expertise is appreciated. I'm not working tomorrow and I want this brake issue resolved so I can move on to the next issue.
I've replaced the master cylinder. I bench bled it as perfectly as can be done.
I bled the front as they were the ones that were originally taken off allowing air in.
Then I bled all 4. Passenger Rear/Driver Rear/Passenger Front/Driver Front.
I am running Clear brake fluid out of all four and I see no air coming out.
I also took the cover off the parking brake mechanism. It was all gummed up in there. Sprayed with PB Blaster and it freed up the mechanism. Parking brakes now work correctly, instead of being stuck on.
Issue: I need to pump brakes three times to get any reaction- At 20 MPH or so, the first pump goes to the floor, it tightens the brakes the provides minimal stopping power.
Second pump goes half way, brakes starting to react.
Third pump, brakes feel hard, (as they should) and the brakes react like they should.
Could it be:
1. I took the front calipers off. Did I put them on correctly? The bleed valve is on the bottom. I'm wondering if I got driver and passenger side swapped. Don't even know if its possible.
2. There is an adjustment bolt behind the master cylinder. Does that need to be adjusted?
Any expertise is appreciated. I'm not working tomorrow and I want this brake issue resolved so I can move on to the next issue.
11-11-2012, 07:36 PM
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yep!
I was wondering if anyone remeobered the ABS !
thats a whole other brake system in itself that has lots to do with fluid and what gets fluid/when and how much.
The FSM has the process for bleeding ABS.
Or, the short cut is just as described...bleed as well as you can, roll the car running and stomp the pedal a couple times. Do the roll & stomp a cpl times. This will throw another cycle of the abs pump that helps move fluid where you can't make it move. Each time you roll, the ABS will self test and cycle the pump. Pound the pedal and that forces an ABS pump & dump cycle. There is close to a mile of additional tubing and other stuff in the ABS system and pump hidden behind the seat. Lots of places for air to hide..
That should help chase any remaining air toward the calipers. Go find a set of self bleeders...screws with check valves so you can open them to let fluid squirt out but they won't let air back in.
I was wondering if anyone remeobered the ABS !
thats a whole other brake system in itself that has lots to do with fluid and what gets fluid/when and how much.
The FSM has the process for bleeding ABS.
Or, the short cut is just as described...bleed as well as you can, roll the car running and stomp the pedal a couple times. Do the roll & stomp a cpl times. This will throw another cycle of the abs pump that helps move fluid where you can't make it move. Each time you roll, the ABS will self test and cycle the pump. Pound the pedal and that forces an ABS pump & dump cycle. There is close to a mile of additional tubing and other stuff in the ABS system and pump hidden behind the seat. Lots of places for air to hide..
That should help chase any remaining air toward the calipers. Go find a set of self bleeders...screws with check valves so you can open them to let fluid squirt out but they won't let air back in.
A mile of tubing? Seriously?
11-11-2012, 08:12 PM
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I may not have been the first person to put calipers on the wrong side!
http://forums.corvetteforum.com/c6-t...akes-whoa.html
http://forums.corvetteforum.com/c6-t...akes-whoa.html
11-11-2012, 10:27 PM
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I fixed it.
Went outside, using a flashlight in my mouth, swapped the calipers followed up by bleeding the front only.
My brakes are finally correct.
I did the lock them up exercise a dozen times. The ABS pump kicked in, growling as it does.
I'll bleed it again the next time the tires are off.
Went outside, using a flashlight in my mouth, swapped the calipers followed up by bleeding the front only.
My brakes are finally correct.
I did the lock them up exercise a dozen times. The ABS pump kicked in, growling as it does.
I'll bleed it again the next time the tires are off.
