[Sirrotica]

My 95 3500 HD popped a brake line yesterday that runs from the ABS unit to the LF flex hose, so I made a new one from Nicopp line, installed it, and as I always am, I have no second person to help bleed it, same scenario over the last 50 years of wrenching.

I left the lower connection loose at the flex hose, refilled the front half of the master cylinder and gave it a few gentle pumps at the very top of the stroke to start a siphon. Same result as always over the last 50 years. The fluid drips from the connection for a minute or two, I tighten the connection. jump into the cab and start the truck and test the pedal. It holds just fine, and is right at the top of the travel, done and done. No vacuum pumps, no pressure bleeders, and no second person to pump, and hold the pedal. I performed the bleeding by myself, with brake fluid, gravity, and time. Probably in less time than it took to type this.

Just wanted all the doubters that say, "it can't be done" to know I just did it, with the same results I've had over the last 50 years. I never opened the bleed screw on the caliper because it never emptied the caliper. I bled it at the lowest connection that was opened, same as usual. No sense in trying to open a bleed screw that is 25 years old if you don't have to. I had enough fun trying to save the flare nuts to reuse on the new line (special application, not easy to come by at most parts stores). Also saved me a 20 mile round trip. Heat was my friend, as most times in a corroded fastener application.

[PontiacJim1959]

NO WAY!!! Blashemy! On an ABS system?! Just wait until the other brake bleeding guru's read your post. Burn him at the stake I say!

Funny how you do something so simple as gravity feed bleed, and all the experts who took that Brake 101 course by reading the contemporary Hot Rod magazine become doubting Thomas' and brake technicians.

I have done the gravity bleed on non-ABS brakes and really don't see why it would not work on them. I have not messed with many contemporary cars, but if I am not mistaken, the early ABS had a magnet and exciter ring? Had nothing to do with the fluid part of the brake system. Now that may have changed, but as I said, I don't mess much with newer vehicles.

You know you just opened a can of worms, right? LOL

[Sirrotica]

It ain't the first ABS system I've gravity bled, won't be the last. The later, more sophisticated electronic systems in the really late models probably can't be bled like this. From what I've read it requires a scanner to evacuate the air from the ABS and lines. I'll probably never own one of those though. Since GM did away with Pontiac, I'm committed to only driving Pontiacs til I quit driving, or I die, so the newest car I'll ever own is a 2010, last year for Pontiac.

When I met my wife she owned a 1999 chrysler stratus and I also had to replace a rear flex hose on it. I has ABS, and I gravity bled that also.

The doubters can't believe you can bleed even old cars with gravity bleeding, ya gotta have 2 people, a vacuum pump, or a pressure bleeder. The laws of physics never change and a siphon still works today same as it did ever since they've been putting fluid inside of pipes, it will seek the lowest point, and air will always rise to the top of a fluid column.

Just wanted to keep the record straight, it works on everything I've worked on so far, up to, and including my wife's 2008 Vibe, which is in the 310,000 mile range on the odometer. The Vibes quit registering at 299,000 miles. My stepsons girl friends Vibe also quit registering miles just before it hit 300.000 miles, must be a Vibe thing........

[Ben M.]

The only ones I've never been able to gravity bleed are the really modern cars with solenoids in the line, usually a regenerative energy recovery braking - hybrids and electronic cars. Those require a diagnostic hookup and a computer.

[Sirrotica]

Originally Posted by Ben M.

The only ones I've never been able to gravity bleed are the really modern cars with solenoids in the line, usually a regenerative energy recovery braking - hybrids and electronic cars. Those require a diagnostic hookup and a computer.

Unless I live to be 100, I don't see any hybrids, or electrics in my future, and yes those would be the cars I was talking about that would require a separate source to operate the brake system independently of the onboard brake system. Mike Garblik recently made a post that certain systems required an auxiliary control to bleed them, I thought he said a scanner, but it could have been a computer to command the system.

Anyway, if I did live to 100 doubtful I'd be working on my own stuff or anyone else's. My mother just turned 99 at the beginning of this month, and rides a scooter because of the impairment of her left leg, add to that arthritis. Scooters have manual brakes, no bleeding required, but the are electric powered.............LOL

Maybe Tesla will be making scooters by then. I could pull wheelies in the halls of the assisted living center...........

[Chief of the 60's]

Originally Posted by Sirrotica

My 95 3500 HD popped a brake line yesterday that runs from the ABS unit to the LF flex hose, so I made a new one from Nicopp line, installed it, and as I always am, I have no second person to help bleed it, same scenario over the last 50 years of wrenching.

I left the lower connection loose at the flex hose, refilled the front half of the master cylinder and gave it a few gentle pumps at the very top of the stroke to start a siphon. Same result as always over the last 50 years. The fluid drips from the connection for a minute or two, I tighten the connection. jump into the cab and start the truck and test the pedal. It holds just fine, and is right at the top of the travel, done and done. No vacuum pumps, no pressure bleeders, and no second person to pump, and hold the pedal. I performed the bleeding by myself, with brake fluid, gravity, and time. Probably in less time than it took to type this.

Just wanted all the doubters that say, "it can't be done" to know I just did it, with the same results I've had over the last 50 years. I never opened the bleed screw on the caliper because it never emptied the caliper. I bled it at the lowest connection that was opened, same as usual. No sense in trying to open a bleed screw that is 25 years old if you don't have to. I had enough fun trying to save the flare nuts to reuse on the new line (special application, not easy to come by at most parts stores). Also saved me a 20 mile round trip. Heat was my friend, as most times in a corroded fastener application.

Just replaced 2 brake hoses and 1 caliper on the front of a PT Cruiser this past weekend. Bled them the same way. Perfect brake pedal.

[track73]

I have changed master cylinders and didn't have to bleed the system as long as the master was bled.

[Sirrotica]

Just wanted to keep the record straight, it works on everything I've worked on so far, up to, and including my wife's 2008 Vibe, which is in the 310,000 mile range on the odometer. The Vibes quit registering at 299,000 miles. My stepsons girl friends Vibe also quit registering miles just before it hit 300.000 miles, must be a Vibe thing........

Totally unrelated to brake bleeding is the Vibe speedometers. I just did some research on them, and the odometers are only programmed to go to 299,999 miles and shut off. Only way to keep track of them is to have them reset to a lower number, or buy a speedometer head from another car and plug it into your car. I'm not sure how many PY members have Vibes on this board, but it's good to know they commonly go over 300,000 miles where the odometer quits functioning.

My wife's car quit about a year and a half ago, but since she's home based with her job now, she doesn't accumulate the miles like she once did as a home care nurse.

You can also keep track of the trip odometer, but that's kind of a PITA.

[67drake]

Originally Posted by track73

I have changed master cylinders and didn't have to bleed the system as long as the master was bled.

Same here.

[grivera]

Does anyone know if a 2008 Toyota Tacoma or a 2011 Nissan Altima and 2015 Lexus RX350 can be gravity bled?

[Kenth]

Part of bleeding brakes is replacing old moisture contaminated brake fluid in some three years interval.
Gravity bleeding at the hose flange at caliper wont do that.
It would certainly be needed if the brake line rusted off!

[Mr Anonymous]

Ive done lots of brakes, and the guy that decided the 88-98 GM Trucks needed a quick take up master cylinder can kiss my sweet ass. I hope when he dies, his angelic form is put on a bus with two stops, the first being Heaven and the second one Hell. Lord knows he wont make the first turn.

[Sirrotica]

The line rusted from a plastic loom that retained road salt resulting in a pinhole in the line. It rusted from the outside in, not from the inside out. I've owned the truck since February of this year and use it for storage on my property. It's not street driven, but still requires brakes to be driven in it's limited capacity as a mobile storage unit.

I'm not concerned about possibly breaking a bleed screw off to exchange brake fluid on a truck that reaches maybe 5 MPH in my backyard,, but thanks for pointing out the obvious.

FWIW, I've never followed the 3 year brake fluid exchange in my own vehicles, and the lowest mileage vehicle I own is a 1999 GP with 111,000 miles on it. Most of my street driven vehicles range from 200- 300,000 miles on them, I probably know a little bit about vehicle longevity and upkeep after taking care of customer vehicles, as well as my own fleet for over 50 years.

I also run my oil for 30-40,000 miles, also not typical in conventional maintenance schedules, but if you properly filter motor oil, you don't have to keep dumping it to keep the oil, and engine clean inside.

I'm not disputing that brake fluid with a DOT 3 is hygroscopic, it is without a doubt, but letting a vehicle sit without regularly being driven is much more denigrating to a brake system, such as hobby cars commonly on this forum.

The water, and sludge definitely settle in the lowest portions of the brake system causing corrosion and deterioration of all components in the system. Exchanging brake fluid taken from the highest point of a caliper (the bleed screw) isn't going to remove anything from the bottom of the caliper cylinder, is it?

All that being said, I'm not concerned about draining, and refilling the brake fluid in this vehicle.

[Chief of the 60's]

Originally Posted by Mr Anonymous

Ive done lots of brakes, and the guy that decided the 88-98 GM Trucks needed a quick take up master cylinder can kiss my sweet ass. I hope when he dies, his angelic form is put on a bus with two stops, the first being Heaven and the second one Hell. Lord knows he wont make the first turn.

LMAO!

[mgarblik]

Brake bleeding is always a fun topic. Like Sirrotica, I work alone 95% of the time. Gravity bleeding works great nearly all the time. I have a venturi style vacuum bleeder as well. To save time I often use it to start the bleeding procedure faster, especially in cars with ABS where fluid to the calipers passes through the ABS modulator first before getting to them. Vacuum speeds the process. Once flowing fluid, I remove and let it gravity bleed. I have XM radio in my shop and listen to the 60's mostly. Once the fluid is flowing, I let each wheel gravity bleed 2 songs, about 6 minutes each. That gives me a great pedal almost every time. Some vehicles with ABS can be a bear to get the air out of if the system has gone dry. (ABS modulator). Some have bleeder screws on the unit, which helps. They can be gravity bled. Some don't. The scan tool in bleed mode really just energizes all the valves and solenoids in the ABS unit and helps vent any tiny air bubbles to the MC. I have had some GM trucks I had to scan tool bleed 6 cycles to get a nice pedal. Changing brake fluid is a good idea as it absorbs water. I change fluid for customers all the time. ATE now sells brake fluid in 3 colors, Amber, green and red I think. You suck out the MC and put a different color fluid in the MC. Then when you bleed the brakes at the wheels, you look for the color change to know you have the old stuff out. Kind of a neat idea.

[Sirrotica]

Mike, it would be better yet if you had a product that changed color to let you know when it should be changed. Identify when the water content was above a certain point.

If I remember correctly there are some test strips to identify when it should be changed, but I'm not certain that's correct. I could be thinking of coolant PH straps.

I do know there are millions of vehicles that are on the road that have their born with fluid still in the system years past thev3 year suggested time frame.

[Kenth]

Originally Posted by Sirrotica

Exchanging brake fluid taken from the highest point of a caliper (the bleed screw) isn't going to remove anything from the bottom of the caliper cylinder, is it?

Not if you bleed by gravity only.
I have found the fluid inlet often sits lower, close to the bottom of the "well", than the bleeder screw.
Change the fluid is best done by the "two person" method or pressurize the master cylinder or using the vacuum method at the bleeder valve.
The bad fluid needs to be pushed or sucked out of the system.

FWIW

[mgarblik]

Gravity bleed to refresh the fluid would work like this. You would remove the old fluid, as much as you can from the MC reservoir. You can use vacuum or even swab it out with paper towels. ( a real mess). Then fill with fresh fluid and keep refreshing it as you gravity bleed. The bleeder is always at the top of each hydraulic unit, wheel cylinder or caliper. Fluid line is always below the bleeder. It may not be 100% perfect, but you will get most of the old fluid out with some patience. When I do a flush, I use a vacuum bleeder to save time and exchange more fluid faster. But I ALWAYS finish with a gravity bleed because I want all the air out and a firm pedal. We have to teach 1 person bleeding because no shop is going to let 2 people at $125.00 an hour each bleed someones brakes. Also, most car enthusiasts work alone.

[Sirrotica]

Originally Posted by Kenth

Not if you bleed by gravity only.
I have found the fluid inlet often sits lower, close to the bottom of the "well", than the bleeder screw.
Change the fluid is best done by the "two person" method or pressurize the master cylinder or using the vacuum method at the bleeder valve.
The bad fluid needs to be pushed or sucked out of the system.

FWIW

I've rebuilt plenty of calipers/wheel cylinders that were flushed by the 2 person method that were loaded with sediment. I always rebuild any brake components myself if the core is salvageable, so I've been inside of many hydraulic brake systems. If I can buy a kit for the vehicle I rebuild the part myself, simply because I don't trust the rebuilders. Unless the vehicle is low mileage, they all have sediment in them

Sorry, not buying that your going to remove all the crap in a caliper just by bleeding them with 2 people, I've seen the results myself.

Here in Ohio we have high humidity, and road salt 3-4 months of the year, flushing the hydraulic portion of the system could get you a tiny bit more life from the system, too many negative things in the environment here that just replacing fluid won't help.

One more thing, due to the road salt (recently we started getting liquid calcium, which is even more corrosive than just road salt) we live with year after year, the bleed screws are usually frozen, trying to bleed them may end up, either a very expensive proposition (parts replacement), or labor intensive drilling the bleed screws out and trying to save the core) when the bleed screw shears off.

Try explaining to your customer that you were going to flush the brake fluid for them, and now the bill is $500 because of the damage you did trying to save them money by flushing the brake fluid.

Did you save them any money overall? Did you make any money, or did you donate a lot of time, and not get paid for it?

That goes over like a lead balloon, who pays the bill? Do you eat the parts, and labor to keep the customer? Or do you charge them for parts, and labor, and piss them off so they never come back?

Explain to them up front that the flush could be between $50 to $500?

If it makes you feel better to flush systems, then have at it, the parts wear no matter how much you flush the system. I don't recall seeing any vehicle go 200,000 miles with out rebuilding/replacing something in the hydraulic portion of the brake system.

[Ben M.]

Originally Posted by Kenth

Change the fluid is best done by the "two person" method or pressurize the master cylinder or using the vacuum method at the bleeder valve.
The bad fluid needs to be pushed or sucked out of the system.

Whenever I've done brakes that were old or cruddy and the customer didn't want to replace the parts, I pull the bleeder screw, clean it out, and attempt to clean out the bottom of the wheel cylinder or caliper of as much as I can (or at least free up the hole). Once I've done that I get clear plastic tubing and a coke bottle, stick clean brake fluid in the bottom to cover up a significant portion of the bottle and hose, then push the pedal inside the car to force nasty fluid and trash out. Once the fluid flows out of the bleeder into the hose cleanly, that side is done and I repeat with clean fluid for the remaining bleeders. Then I finish it up with a gravity bleed to make sure the air bubbles are gone and the pedal is nice and firm.

Takes longer, but it gets done right to me and the fluid is all fresh inside the lines and the majority of the trash is gone.