How much brake fluid per line to flush?
07-01-2019, 10:22 AM
#1
Senior Member
Thread Starter
How much brake fluid per line to flush?
The front and rear pistons were changed with the brake lines. Records show 2013. I think front abs and it looks like no more free vin checks for the mechanical details. 128K miles. Since then I just made sure the brake reservoir showed full. There is no brake problem.
Recently, though, I found out that the fluid needs to be changed, as completely as possible. So how much fluid should I measure to be confident that each line and pistons are filled with fresh fluid?
I have an old toyota camry which is why I found out about the fluid flushing. Recommendation for 98 camry seems to be about 250ml (bit over one cup). For anybody interested. One poster ground off the cone at the end of the bleeder screw and use that for bleeding. Many would put vasoline around the screw to stop air. Above poster used a hand vacuum pump. I bought a mityvac at the time and it did not work, so I thought. Per above poster, I made a bottle that keeps vacuum.
BTW, I changed the metal brake lines with premade lines with some extra lengths that is just bent to keep them more or less in the factory position. So I will make sure to add extra fluid.
Recently, though, I found out that the fluid needs to be changed, as completely as possible. So how much fluid should I measure to be confident that each line and pistons are filled with fresh fluid?
I have an old toyota camry which is why I found out about the fluid flushing. Recommendation for 98 camry seems to be about 250ml (bit over one cup). For anybody interested. One poster ground off the cone at the end of the bleeder screw and use that for bleeding. Many would put vasoline around the screw to stop air. Above poster used a hand vacuum pump. I bought a mityvac at the time and it did not work, so I thought. Per above poster, I made a bottle that keeps vacuum.
BTW, I changed the metal brake lines with premade lines with some extra lengths that is just bent to keep them more or less in the factory position. So I will make sure to add extra fluid.
Last edited by carpdad; 07-01-2019 at 10:25 AM.
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carpdad (07-02-2019)
07-02-2019, 07:20 AM
#3
To bleed by yourself, you can put a piece of clear tubing on the end of the bleeder valve with the other end in a bottle of brake fluid. Then open the bleeder and let fluid flow from the master cylinder down. A few pumps might be needed. Close the bleeder when you see clean looking fluid coming out.
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carpdad (07-02-2019)
07-02-2019, 10:19 AM
#4
Senior Member
Thread Starter
I guess that trucks with longer tubes and maybe bigger brake pistons would take more fluid. But, raski, do you mean a quart for each wheel or for all of them? Clear fluid would be one way to see it but I would like to have a better way to know. I edited the truck specs in the signature but I still don't know why the specs don't always show up. Also I'm not sure what my brake specs are. It is 96 300 manual with front disc and rear drums. No changes done to the brake system. Original booster and master cylinder.
07-02-2019, 10:31 AM
#5
Senior Member
Here's your protocol, and it works every time on these trucks:
1) Remove all fluid from the master with a turkey baster and replace with clean fluid.
2) Bleed the rear passenger side until you see clean fluid - this will take the longest of all 4 wheels. Make sure the master does not run dry.
3) Bleed the rear driver's side - this won't take long at all because clean fluid has already gotten to the rear axle in the previous step.
4) Bleed the RABS valve - some people skip this step, its debatable if its really necessary.
5) Bleed the front passenger
6) Bleed the front driver, top off the master cylinder
All the while making sure the master never runs dry. If it runs dry you have to start from the beginning.
1) Remove all fluid from the master with a turkey baster and replace with clean fluid.
2) Bleed the rear passenger side until you see clean fluid - this will take the longest of all 4 wheels. Make sure the master does not run dry.
3) Bleed the rear driver's side - this won't take long at all because clean fluid has already gotten to the rear axle in the previous step.
4) Bleed the RABS valve - some people skip this step, its debatable if its really necessary.
5) Bleed the front passenger
6) Bleed the front driver, top off the master cylinder
All the while making sure the master never runs dry. If it runs dry you have to start from the beginning.
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carpdad (07-03-2019)
07-02-2019, 11:05 AM
#6
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Ford specifically recommends NOT bleeding or flushing any brake lines, except when necessitated by other repairs or failures. It's more likely to create new problems than to prevent any.
Every 2~5 years, remove all the fluid from the reservoir using suction (turkey baster, etc.) and refill with DOT3 from a sealed bottle. That's all.
If you ever notice that the fluid is the wrong color or consistency during a brake service (pads, shoes, rotors, drums):
While all the slave cylinders are fully-compressed, empty & refill the reservoir as above. Then extend all the slaves near their limits (DO NOT ALLOW any slave piston to hyperextend, OR the reservoir to run dry) by pumping the pedal. This fills the slaves with fresh fluid & flushes the lines. Then compress each one fully (DO NOT ALLOW fluid to overflow the reservoir - it will strip paint from the booster & body), removing fluid as necessary from the reservoir. This flushes the lines & dilutes the last bit of old fluid in the slaves. It's also how you "reverse bleed" the lines after any hydraulic repairs because it carries any air in the lines or slaves back to the reservoir. The bleed nipples on the slaves do not need to be opened.
Every 2~5 years, remove all the fluid from the reservoir using suction (turkey baster, etc.) and refill with DOT3 from a sealed bottle. That's all.
If you ever notice that the fluid is the wrong color or consistency during a brake service (pads, shoes, rotors, drums):
While all the slave cylinders are fully-compressed, empty & refill the reservoir as above. Then extend all the slaves near their limits (DO NOT ALLOW any slave piston to hyperextend, OR the reservoir to run dry) by pumping the pedal. This fills the slaves with fresh fluid & flushes the lines. Then compress each one fully (DO NOT ALLOW fluid to overflow the reservoir - it will strip paint from the booster & body), removing fluid as necessary from the reservoir. This flushes the lines & dilutes the last bit of old fluid in the slaves. It's also how you "reverse bleed" the lines after any hydraulic repairs because it carries any air in the lines or slaves back to the reservoir. The bleed nipples on the slaves do not need to be opened.
04-22-2020, 07:37 PM
#7
Ford specifically recommends NOT bleeding or flushing any brake lines, except when necessitated by other repairs or failures. It's more likely to create new problems than to prevent any.
Every 2~5 years, remove all the fluid from the reservoir using suction (turkey baster, etc.) and refill with DOT3 from a sealed bottle. That's all.
If you ever notice that the fluid is the wrong color or consistency during a brake service (pads, shoes, rotors, drums):
While all the slave cylinders are fully-compressed, empty & refill the reservoir as above. Then extend all the slaves near their limits (DO NOT ALLOW any slave piston to hyperextend, OR the reservoir to run dry) by pumping the pedal. This fills the slaves with fresh fluid & flushes the lines. Then compress each one fully (DO NOT ALLOW fluid to overflow the reservoir - it will strip paint from the booster & body), removing fluid as necessary from the reservoir. This flushes the lines & dilutes the last bit of old fluid in the slaves. It's also how you "reverse bleed" the lines after any hydraulic repairs because it carries any air in the lines or slaves back to the reservoir. The bleed nipples on the slaves do not need to be opened.
Every 2~5 years, remove all the fluid from the reservoir using suction (turkey baster, etc.) and refill with DOT3 from a sealed bottle. That's all.
If you ever notice that the fluid is the wrong color or consistency during a brake service (pads, shoes, rotors, drums):
While all the slave cylinders are fully-compressed, empty & refill the reservoir as above. Then extend all the slaves near their limits (DO NOT ALLOW any slave piston to hyperextend, OR the reservoir to run dry) by pumping the pedal. This fills the slaves with fresh fluid & flushes the lines. Then compress each one fully (DO NOT ALLOW fluid to overflow the reservoir - it will strip paint from the booster & body), removing fluid as necessary from the reservoir. This flushes the lines & dilutes the last bit of old fluid in the slaves. It's also how you "reverse bleed" the lines after any hydraulic repairs because it carries any air in the lines or slaves back to the reservoir. The bleed nipples on the slaves do not need to be opened.
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04-22-2020, 08:37 PM
#8
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It's a hydraulic system - opening it risks introducing air, or causing leaks, or breaking fittings, or rounding off fasteners, or...
Using the wrong brake fluid is technically illegal on public roads, and always dangerous - even if it's strictly a track car. The system is designed to work correctly with the original fluid - not any other. Brake fluids with higher DOT numbers are NOT "better"; they're just newer (created after those with lower numbers). It's like putting R-32 into a system designed for R-12; it's NOT an improvement, won't work right, and may cause damage. Just because you haven't NOTICED any problems yet, doesn't mean there aren't any.
Using the wrong brake fluid is technically illegal on public roads, and always dangerous - even if it's strictly a track car. The system is designed to work correctly with the original fluid - not any other. Brake fluids with higher DOT numbers are NOT "better"; they're just newer (created after those with lower numbers). It's like putting R-32 into a system designed for R-12; it's NOT an improvement, won't work right, and may cause damage. Just because you haven't NOTICED any problems yet, doesn't mean there aren't any.
04-22-2020, 09:55 PM
#9
DOT 4 has a higher boiling point. There were guys out there boiling the DOT 3. The two are also compatible. My point is changing the fluid and bleeding the brakes never caused any issues. I’m not changing the type of fluid I’m going to run, just want fresh fluid and I prefer to change it all. I just started pulling a 7,000 lb trailer so I’m upgrading pads and prefer to have all new fluid. I may just drain the master cylinder and refill with new, but prefer to replace all of it. With the proper tools and knowledge I don’t see where I’m going to have any issues. Auto manufacturers don’t want anyone else working on their cars. At 100+ per book hour why would they. I’ll do a little more research. Thanks for the response. Also I’ll be using a pneumatic bleeder so I’m not going to be pumping the brakes to bleed them.
Last edited by Davet435; 04-22-2020 at 09:57 PM.
04-22-2020, 10:03 PM
#10
Brake fluid is hydroscopic, it absorbs moisture. Wet brake fluid has a lower boiling point than dry brake fluid. When your brake fluid boils the moisture turns to steam a gas. You then have no brakes. When brake fluid is fresh it is almost clear. After it absorbs water it turns dark. If your brake fluid is dark it needs to be changed.
For all practical purposes DOT 3 and 4 are interchangeable. DOT 4 has a synthetic base and higher boiling point but absorbs moisture more quickly. Most automakers now recommend brake fluid change every few year but few do it. Most folks don't use their brakes hard enough to experience brake boil. Moisture will cause corrosion in the brake system.
DOT 4 generally has a higher boiling point than DOT 3. If you plan on tracking your truck you can get DOT 4 brake fluid with much higher boiling point for much more money that is completely legal in your truck.
For all practical purposes DOT 3 and 4 are interchangeable. DOT 4 has a synthetic base and higher boiling point but absorbs moisture more quickly. Most automakers now recommend brake fluid change every few year but few do it. Most folks don't use their brakes hard enough to experience brake boil. Moisture will cause corrosion in the brake system.
DOT 4 generally has a higher boiling point than DOT 3. If you plan on tracking your truck you can get DOT 4 brake fluid with much higher boiling point for much more money that is completely legal in your truck.