Brake Flushing

[hammersley]

Over at teh Ford Site a guy said:

I bought a high dollar vacuum flush machine which works OK for the fronts but not well
on the rears. If I had to do it over, I'd have just spent $1 for some small diameter vinyl tubing to slip over the bleed screw and let gravity do the job.

My advice is to suck out all you can from the reservoir w/ turkey baster and tubing, hypo, or whatever, and refill w/ fresh fluid. Attach a piece of vinyl tube to the bleed screw and put the other end in a container so you can catch the fluid. Open the bleed screw a few turns (start at the right rear). Gravity will let the fluid flow. Do it till you see fresh fluid come out the tubing then close the screw and repeat for the other rear and then the fronts. Trucks w/RABS have a valve that makes vacuum bleeding from the
wheels less effective. Just check the reservoir every 10 minutes or so to make sure that it doesn't run out of fluid and add as required (you'll get a feel for how fast it goes). No need to pump the brakes as you need two people and can introduce air if you don't close the bleed screw at the right time (but it is faster). The job takes about 32 oz of fluid and will take about 1-2 hrs by gravity with a minimum of attention. Save the money you'd spend on a fancy bleeder for other goodies!

Has anybody flushed their brakes this way - seems easy... .

 

[Deezal Man]

Never heard of the gravity method. Sounds as if it works. . but seems a little slow.

I do things slightly different, but it works best with two people.

Like you, I remove the old fluid from reservoir into a clear bottle, add new fluid.

Then I attach a short piece of tubing to the bleed screw, and put the other end into the bottle with the old fluid. The old fluid creates an air seal. . keeping air from entering the system.

Then I crack open one of the rear bleed screws, and have the other person pump the brake pedel till I see fresh fluid.

Finally, I tell him to press the pedel slow, while I tighten the bleed screw. This ensures no air or old fluid is pulled back into the system.

While I move the next wheel, the other guy refills the reservoir and the process repeats.

We can usually flush the entire system in about 15-20 minutes... no rushing.

You could do this yourself but it would take a bit longer.

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98. 5' 24v 2500 Auto/3. 54 4x4 SB QC 285-75-16's on Alcoa's. Everything but leather. PIAA 1200's, AMSOIL dual filter relocation system, Smittybuilt Stainless Steel Nerfs, Rhino Liner(Junk), K&N air filter(For Sale)15 year AMSOIL dealer. Time permitting, Soon to include Ultra-lite Pyro,0-50lbs boost, Trans temp in the pillar. Rancho 9000's with in cab adjustment.

 

[PHaller]

Suck out all the old brake fluid from the resevoir and refill with fresh fluid. Start by bleeding the wheel furthest away from the resevoir, usually the right rear. Have a person step on the brake and crack the bleeder nipple. When the pedal hits the floor, tighten the nipple and have your assistant pump up the brakes. Repeat until fresh brake fluid come out of the nipple. Fill the resevoir and repeat whith the next furthest wheel from the resevoir.
Gravity bleed will not purge all air bubbles from the system. The bubbles will cling to the inside of the brake wheel cylinders and pistons. Stepping on the brakes while the bleeder is open will create turbulence thoughout the bled line to shake loose debris and air.
IMHO, pressure is the proper way to bleed a hydraulic system, either by a pressure port and compressed air or by someone applying brake pressure. Vaccume or gravity will not always remove the air.
After checking the manual, I was surprised to find no service interval for bleeding the brake or power steering fluids. Brakes should be bled every 2 years because dot 1,2,&3 brake fluids absorb water and over time will rust the steel and iron components in the system. It's also important to remove the rubber and iron particles suspended in the fluid because they will cause further wear. Dot 4 fluid is silicone based and does not absorb water as efficently as the earlier fluids do but dot 4 is NOT recommended for use in our trucks. It is also incompatable with mineral oil based fluids. Do not mix them.
Power sterring fluid should be changed every 4 years or so and the same procedures are generaly used.
-Paul R. Haller-

 

[Ram_Kowboy]

I have used the gravity method many times. Just remember to leave the cap off the master cylinder resevoir while you are gravity bleeding. If the cap is on the resevoir it acts just like when your finger is over the top of a straw, the fluid cannot bleed out.

Just a word about pressure bleeding with the brake pedal. When the bleeder screw is opened and your pedal travels down towards the floor, you are moving the plunger and seals into an area that have not seen any action for awhile. As a result the seals can be damaged. When we pressure bleed with the pedal, the person inside the vehicle would put his left foot under the pedal to prevent the pedal from traveling all the way to the floor. Or another way is to open and close the bleeder screw quickly so the pedal does not travel all the way to the floor.

My prefered way is with a pressure bleeder attached to the master cylinder resevoir. But this operation usually rules out the do-it-yourselfers as most of us to not want to spend the money neccesary for a power bleeder.

So for my $. 02 worth. 1st choice, pay someone for a power flush. 2nd choice, gravity bleed, 3rd choice, pressure bleed with a friend behind the wheel.

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98 Properly Valved 4x4 SWB QC ISB A/T Metallic Red w/ tan cloth interior, DC nerf bars, DC two piece mud-flaps, 275 h. p. injectors, Monroe Gas Magnums, Armor Tuff spray in bed liner, Goodyear Wrangler ATS 285/75r/16, BD Heavy Duty Valve body. Walker 21468 thru flow muffler,Cobra 29 NWST CB. American Racing Wheels. Power Edge EZ control module.

 

[kaffine krazed]

Originally posted by Paul R. Haller:
Brakes should be bled every 2 years because dot 1,2,&3 brake fluids absorb water and over time will rust the steel and iron components in the system. It's also important to remove the rubber and iron particles suspended in the fluid because they will cause further wear. Dot 4 fluid is silicone based and does not absorb water as efficently as the earlier fluids do but dot 4 is NOT recommended for use in our trucks. It is also incompatable with mineral oil based fluids. Do not mix them.
-Paul R. Haller-

DOT 4 is not silicone that is DOT5.

I use a vacuum bleeder to do the brakes. I haven't had a problem with ABS doing it this way.

 

[1tuffram]

In regards to DOT 3 and DOT 4 fluid, I know you can't mix the two, but I see brake fluids (Valvoline Synpower) which claim to be compatible with both DOT 3 and DOT 4. Can these fluids be used without harm?

Also, can any DOT 3 brake fluid be used? I saw some stuff by Castrol which claims to be specially formulated for use in ABS systems. Does the RAM 4 wheel ABS systems require a special type of DOT 3 brake fluid?

 

[sam peterson]

kowboy is right, dot 5 is silicone not dot 4.
dot 4 will mix with 3 but why use 3 when you can get the benefit of higher boiling point with dot 4. don't push the pedal all the way down as he suggests and don't start the motor. ---Sam

 

[Alan Reagan]

I did it that way on a Corvette after installing new calipers. Slow but worked great. I was wondering if it would work that way on my truck with the ABS. Thanks for the tip. Based on the recommendation to do it annually, I'm getting psyched to do it now.

 

[sam peterson]

to add to the previous post--a lot of the brands use glorified marketing techniques to make you think they have something special, but the fact is if you keep the system clean with fresh dot 3 or 4, that is what is needed for the antilock systems. moisture is what messes up the abs unit.

 

[Jim Guidry]

MityVac, baby!! Best thing since sliced bread for bleeding brakes. Bought mine at NAPA for 25 bucks or so. Put the tube on the bleeder, crack it, apply about 25 lbs of vacuum and out she comes. (I drain my master cylinder reservoir first and fill with fresh fluid. )
Also great for sucking power steering fluid and rear end oil out.
http://www.mityvac.com/kits.html

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'96 Regular Cab, 118k, SLT 2WD auto 3. 54, Vista topper, Pillar-mounted Autometer Boost/Pyro, transmission temp and oil pressure guages under dash, starwheel spun, stock plate and housing slid ALL THE WAY!!

 

[Skydiver]

I have seen the gravity method used. I prefer the 2 man method because of the turbulance that will remove air and trash.
After I changed my front pads for the 1st time I noticed my ABS light was on. My mechanic friend told me that the ABS system has a censor of some type (c'ant remember what type)that will detect contaminates. These contaminants were from me compressing the calipers. Anyway before I could find time to flush the brake system the ABS light went off which was 3 days later. Have seen many older cars and trucks have one of there calipers fail to completetly release the pads because the flexable tubing was clogged so bad. It was acting as a one way check valve. Changing the brake fluid is important. On a safty note,you w'ont ever get brake in your eyes more than once. I have never had it happen to me but from what I have heard it burns much more than lemon juice.

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96 3500 Feline deceased. Ready to upgrade. 86K. auto,3. 54,Ext. cab.
K&N air,Star wheel spun,silencer ring hanging on a nail.
Truck looks just like the truck on left side of page 6 issue 31.

 

[PHaller]

You guys are right of course... My mistake on calling dot 4 silicone based. It is dot 5. Having a senior moment.
-Paul R. Haller-

 

[tlippy]

Wish this advice had been around a year ago when I changed the fluid for the first time. One of my front fittings had mud in it, so I just unscrewed it and took it into the garage to clean out. Buy the time I got back under the truck, I had a cup of brake fluid under the RF wheel. Gravity does work!

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99' Quad 4x4 A/T LB 3. 54 30K Miles.
26' Terry w/slide 7500GVWR
"KISS your truck and it will be forever faithful"

 

[mikepvg]

Do the above methods work on trucks w/ RWAL or 4Wh ABS?
DC manual says to bleed in order:
1)master cylinder
2)rear anti-lock valve
3)combination valve
4)front anti-lock valve
5)left rear wheel
6)right rear wheel
7)right front wheel
8)left front wheel
Basically, after looking at master cylinder, combination valve etc. . I have no idea what the manual is talking about. Its not obvious to me how to bleed these first.
Can I bleed all 4 wheels & get the new fluid everywhere it shoule be in this type of system?
I've bleed a lot brakes before but no anti-lock systems. I need some TDR expert advice w/ this one.
Thanks!
Mike
#ad



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94 2500HD 5sp 4. 10LSD 4X4 ABS w/GearVendor OD, K&N Oval w/ Pre-Filter, Straight Exhaust, Geno's Fumotovalve, AW-Direct Idle Controller, Mag-Hytec Rear, 123K miles. NRA Member. V1.

 

[sam peterson]

forget the word ABS and bleed the system like you would anything else. Don't let the resevoir go dry and don't pump the pedal fast to build pressure. If you don't push real hard you probably won't set any warning lights. The truth is you can bleed any wheel any time you want without any problem. ---Sam

 

[John]

I've been considering the purchase of those trick little Speed Bleeders (that replace the OE style bleeders). They have a check ball assembly that is said not to allow air to enter the system. Several on this site have used them (that's where I got the tip)... I just haven't got around to ordering them yet.

 

[mikepvg]

Sam
ABS? What ABS?... .
Advice taken...
Methods mentioned here are:
1)Gravity
2)MityVac suction
3)traditonal 2 man press & bleed

No one mentioned injection, why fight gravity? I've used injection, rebuilding my motorbikes brake system, it is a great way to go if you have to start dry.
#ad

Mike
p. s. My left brake PULL is BACK!
There is only one thing left to do to these brakes... .
#ad

 

[sam peterson]

Pressure bleeding is a good way to flush a brake system. Because of the volumn and pressure it cleans the system out the best. The injection method from the bottom to the top is ok but you have to keep cleaning out the resovoir and you are pushing dirty fluid thru the rabs valve and master cyl.

 

[Steve Roseman]

Skydiver,
You brought back old memories when you mentioned brake fluid in the eyes. About 20 years ago when I was in high school I was helping a buddy bleed the brakes on his parents' car. Since I was young and dumb I'm not afraid to say what happened. We thought since the car had power brakes it needed to be running while we bled them. As the bleeder screw was pointed straight towards my face I cracked it open. Needless to say, the rest of the story includes a lot of water and cussing. I don't know what lemon juice in my eyes feels like, but I don't think anything can measure up to the pain of brake fluid. I guess nowadays somebody could have just handed me a sign... LOL.

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'95 2500 Ext. Cab, 2wd 3. 54 limited slip, auto, TST 230/605 plate, TST low stall T. C. , K&N air filter.