YACT: DIY power brake bleeder...need some suggestions

[TechnoKid]

I'm in the process of making my own power brake bleeder. I'm using a 1/2 gallon garden sprayer from OSH.

What I need to know is it is ok to tap a 1/4"-18 NPT into the plastic tank to put a fitting for a pressure relief valve and a 30 psi pressure guage? For the pressure relief valve, I'm going to be using an air compressor drain cock (Campbell Hausfeld, the twisting kind), is that ok to "bleed" of the presure in the tank? Or should I use a safety valve?

I'll be running a tee off the tap in the garden sprayer tank, and put the relief valve and the pressure gauge on there.

The pressure gauge is a 30psi one from Ace Hardware. Any suggestions on stores that I could go to to get a 30psi gauge with a 1/4" NPT? So far Ace is the only place that has it readily, I don't know exactly what kind of store to go to to get a 30psi gauge; all the Kragen, autozone etc, don't seem to have em, and harware stores like Homedepot and Lowes have the kind that hookup to your water faucet.

Thanks in advance.

http://www.bmw-m.net/TechProc/bleeder.htm It's very similar to this one here. Maybe I should just buy the tool that Motive makes.

 

[resinboy]

something you may wish to consider is one of the reverse bleeders- they are basically a fluid injector- you introduce brake fluid at the bleeder, and let the air take it's natural course- uphill towards the master cylinder.
If you use a power set-up, you need some kind of WELL fitting adapter at the master- if it leaks even a little, you will run out of fluid very quickly.
My shop uses a vacuum reservoir set-up, with an auto refiller at the master, that works pretty well.

 

[TechnoKid]

Originally posted by: resinboy
something you may wish to consider is one of the reverse bleeders- they are basically a fluid injector- you introduce brake fluid at the bleeder, and let the air take it's natural course- uphill towards the master cylinder.
If you use a power set-up, you need some kind of WELL fitting adapter at the master- if it leaks even a little, you will run out of fluid very quickly.
My shop uses a vacuum reservoir set-up, with an auto refiller at the master, that works pretty well.

I will be using a spare cap that actually fits with little modification; a late model GM cap (about 1-3/4") just needs a gasket to work for my app (Audi/VW).

Do you know a good source for pressure gauges?

TIA

 

[NutBucket]

I think I'll stick with a $20 vacuum pump from autozone BTW, does a power bleeder allow you to properly bleed ABS systems?

 

[GalvanizedYankee]

Do what you will, that is a pretty comprehensive article you linked.

The best pressure bleeders use a bladder that is filled w/brake fluid inside a pressurized container. This keeps air and
moisture from migrating into the fluid. The units that do not use a bladder will force air into the fluid if left for several
days, under pressure.

Brakes are best bled slowly, by pressure or vacuum. This prevents cavitation and a slightly spongy brake pedal that
will result from foaming. I am referring to a match head size ball of air that will form as the foam settles.

The way I bleed brakes is by suction. I pull all the bleed screws out and dry them w/brake clean spray. I lube all the threads with brake assembly grease, it's silicon based and meant for internal use (I got a large tube of Brembo). This is to prevent air sucking by the threads.
I just like seeing the fluid run clear. I use 80cc plastic syringes and slowly draw the fluid out. 80cc=20seconds.

Bleeding the brakes with someone pumping the pedal can be done but is not to be encouraged. Generally the job
gets rushed and again cavitation.

EDIT: Back bleeding, forcing fluid into the bleed screw, works very well as a finishing touch when bleeding motorcycle
front brakes and hydralic clutches because the lines run vertical.

 

[Quixfire]

Originally posted by: galvanizedyankee
Do what you will, that is a pretty comprehensive article you linked.

The best pressure bleeders use a bladder that is filled w/brake fluid inside a pressurized container. This keeps air and
moisture from migrating into the fluid. The units that do not use a bladder will force air into the fluid if left for several
days, under pressure.

Brakes are best bled slowly, by pressure or vacuum. This prevents cavitation and a slightly spongy brake pedal that
will result from foaming. I am referring to a match head size ball of air that will form as the foam settles.

The way I bleed brakes is by suction. I pull all the bleed screws out and dry them w/brake clean spray. I lube all the threads with brake assembly grease, it's silicon based and meant for internal use (I got a large tube of Brembo). This is to prevent air sucking by the threads.
I just like seeing the fluid run clear. I use 80cc plastic syringes and slowly draw the fluid out. 80cc=20seconds.

Bleeding the brakes with someone pumping the pedal can be done but is not to be encouraged. Generally the job
gets rushed and again cavitation.

Great post, the only difference for me is I use teflon thread sealant and a vacuum hand pump.

 

[TechnoKid]

Originally posted by: galvanizedyankee
Do what you will, that is a pretty comprehensive article you linked.

The best pressure bleeders use a bladder that is filled w/brake fluid inside a pressurized container. This keeps air and
moisture from migrating into the fluid. The units that do not use a bladder will force air into the fluid if left for several
days, under pressure.

Brakes are best bled slowly, by pressure or vacuum. This prevents cavitation and a slightly spongy brake pedal that
will result from foaming. I am referring to a match head size ball of air that will form as the foam settles.

The way I bleed brakes is by suction. I pull all the bleed screws out and dry them w/brake clean spray. I lube all the threads with brake assembly grease, it's silicon based and meant for internal use (I got a large tube of Brembo). This is to prevent air sucking by the threads.
I just like seeing the fluid run clear. I use 80cc plastic syringes and slowly draw the fluid out. 80cc=20seconds.

Bleeding the brakes with someone pumping the pedal can be done but is not to be encouraged. Generally the job
gets rushed and again cavitation.

EDIT: Back bleeding, forcing fluid into the bleed screw, works very well as a finishing touch when bleeding motorcycle
front brakes and hydralic clutches because the lines run vertical.

Hey, I was wondering where you get your plastic syringes? I need some to take out fluid from things like power steering resivoirs, etc. I tried turkey basters, but the rubber bulb ended up falling off and slipping once fluid got into it. Another idea I have is using a hand-soap-dispenser pump.

Also, I had an idea about the DIY brake bleeder. You could use a bigger gallon sprayer, then put the whole bottle of brake fluid inside, and stick the sution stick-tube into the bottle. But, if you move the sprayer, the brake fluid bottle will tip. With the homemade bleeder, you must be very careful to not let the level of fluid get low or empty. It causes a violent stream to come out of the sprayer, and causes those "micro" air bubles that you describe.

I built and flushed the brakes yesterday on my dad's Audi, the tool worked great. Took a while to build the tool. I'm am going to flush it one more time to get all of the old fluid completely out.

I need to flush a toyota (Previa) and honda accord/civic, but I don't have an adapter plate buit for the master cylinder cap. I could get the plate from Motive. I may have to resort to gravity bleeding (I will definately have to on the Previa, It's got a weird cap style). Although a long process, gravity bleeding ensures that the master cylinder won't get damaged by pushing the brake pedal too far.

 

[GalvanizedYankee]

I don't believe you fully understood what I posted.

The cavitation is cause as the fluid rushes through the relief port of the master cylinder, IF the brakes are
bled in a high volume manner, flow at the bleed screw must be kept at a low output.

Non-bladder bleeders introduce air and moisture into brake fluid. The only way to use them is they must be clean and
and filled with fresh fluid. Pressured up and used within an hour then unpressurized. Any left over fluid is discarded.

Air will remain in the fluid only to be released when the fluid gets hot (220f), like soda pop on a hot day. This is why
the fluid MUST NOT be left under pressure for more than an hour, max 20psi.

The syringes can be had at medical supply stores or sometimes the Goodwill will have them. They gum-up when exposed to oil or brake fluid after about an hour, so are just a one shot deal They work real good as wood glue
applicators. PM me if you can't find any.



BTW: I was doing brake jobs and tune-ups at 13 for money, rather than mowing lawns as my brother did

 

[Slickone]

galvanizedyankee, forgive my ignorance, but you're talking about two different methods of bleeding when you mention your method w/ syringe, and using a pressure bleeder (w/ or w/out bladder), correct? And the syringe method is like using one of the vacuum pump bleeders, which allow you to open the bleeder screw and pull out fluid at your own pace (and see the fluid easier), and stop when you need to, to add fluid to the master cylinder. Is all correct or am I all confused?
I was planning to buy one of the vacuum pump bleeders since I've always just used the pump the pedal method. Is there one that you recommend that's not too expensive?
Or I might can get a syringe easily. How do you connect it to the bleeder screw?

 

[Quixfire]

Originally posted by: Slickone
galvanizedyankee, forgive my ignorance, but you're talking about two different methods of bleeding when you mention your method w/ syringe, and using a pressure bleeder (w/ or w/out bladder), correct? And the syringe method is like using one of the vacuum pump bleeders, which allow you to open the bleeder screw and pull out fluid at your own pace (and see the fluid easier), and stop when you need to, to add fluid to the master cylinder. Is all correct or am I all confused?
I was planning to buy one of the vacuum pump bleeders since I've always just used the pump the pedal method. Is there one that you recommend that's not too expensive?
Or I might can get a syringe easily. How do you connect it to the bleeder screw?

MityVac is favorite tool for vacuum bleeding brakes.

 

[GalvanizedYankee]

Quixfire offers up a good one. Do not go for a cheap China knock-off. The pumps are weak and the cup is a PITA
to get it to seal right. You can pump like mad and never pull a decent vacuum.

The syringes I got at a garage sale. They work very well for topping off battery water, particularly when working w/small batteries.

I've had several good vacuum pumps and they seem to grow legs/disappear.

Take Mr Fire's advice

 

[scauffiel]

This is what I use and it works really well: http://www.phxsyss.com/

S.

 

[Slickone]

Originally posted by: QuixfireMityVac is favorite tool for vacuum bleeding brakes.

How much is it?

Originally posted by: scauffiel
This is what I use and it works really well: http://www.phxsyss.com/

S.

Which one?


I don't need anything fancy and expensive, just something that will work for the rare times when I need to flush and/or bleed the brakes on my car. Are there any US made bleeders that are cheaper, more for the home DIY mechanic?

 

[Slickone]

^

 

[bmacd]

I highly recommend the Mityvac Brake Bleeder...$34.99 at Sears: http://www.sears.com/sr/javasr/product.do?pid=00947058000&BV_UseBVCookie=Yes&vertical=TOOL

-=bmacd=-

 

[Quixfire]

Slickone,
The plastic Mityvac Brake Bleeder, like the one Bmacd linked to, is about $35.00.

I have the Silver Line model, which made out of metal, and can be found around $50-65 dollars.

The Phoenix system is very expensive, about $200-400.00 dollars depends on the different accessories you get with it.

 

[bmacd]

i used to bleed brakes by hand on my bikes, but now i could never imagine using anything BUT the mityvac. Definitely a wise investment.

-=bmacd=-

 

[GalvanizedYankee]

Got a PM from slickone.

Over the years I have had nothing but bad luck with the plastic vacuum pumps and other mechanics helped themselves to the two pot metal ones I had.

slickone, go with what Quix suggests, the metal pumps have far less problems sealing and last forever. Never loan it out. Remember what I posted above, bleed slowly. It makes a major difference in systems with a small master cylinder
piston diameter, such as, small import cars, bicycles (some have hyd.brks.) & motorcycles.

I much prefer using a plastic syringe because its very positive in it's displacement of fluid. My mother was a nurse and
I have used them since my teens I have 6 boxes of 50 count 80cc The nozzle is quite large but they do come with a reducer for small tubing.

In doing a full system overhaul, like a restoration or installing stainless steel flex lines, sometimes a bubble of air will be trapped at a fitting. Only at this point will I have someone hold moderate pressure on the foot pedal as I go around
and crack open the fittings one at a time, in the hope of further firming up the pedal. This is done after the car has been driven a bit and the brakes bedded in. On some old cars I've had to slip a smooth .004" feeler gage between the piston and wheel cylinder bore to lift the lip of the rubber cup to release an air bubble, thats extreme, it was an early 50's Chrysler.

Never use DOT 5 brake fluid. The best for a sealed system, as all new cars are, is Ford HD DOT 3. It's also the most
hygroscopic (sp). Never use old opened plastic containers, even if they have been kept capped. If you buy quarts
only buy it in a metal container as it will keep much better than plastic.
There is a ton of stuff on line about brake fluid compatibility. I know several racers that almost died from using DOT 5.
I hate the stuff



bmacd: Because bike front brake lines run vertical and can trap air, most racers will back bleed as a finishing touch.
Back bleeding is forcing fluid into the bleed screw back up to the m/c reservoir. A plastic syringe is perfect for this
operation.


Note: When changing lines lube the threads with brake fluid upon assembly. I use the grease thats intended for lubing
caliper piston sealing rings but if I don't have it at hand, I use brake fluid.

 

[Slickone]

Wow, good info. Thanks guys. Looks like the Silver line is $70, which isn't bad. What about this one (metal?)?
And yes, I do plan to add stainless flex lines.

What about DOT 4, and synthetic DOT 3/4 brake fluids?

DOT 5 is silicone fluid right? I've seen a lot of people recommend it. But I don't plan to use it. Many on the Zcar lists I'm on have been using it for a long time. See this or this.

 

[GalvanizedYankee]

Originally posted by: Slickone
Wow, good info. Thanks guys. $50-$65 is do-able. And yes, I do plan to add stainless flex lines.

What about DOT 4, and synthetic DOT 3/4 brake fluids?

DOT 5 is silicone fluid right? I've seen a lot of people recommend it. But I don't plan to use it. Many on the Zcar lists I'm on have been using it for a long time. See this or this.

Read this Text
Ford H.D. DOT3 has a dry boiling point of 550F, thats very good,near best. Wet boiling point of 280F, thats poor.
Buy it in a metal container and it's the racers choice of today. Plus it is cheap enough to bleed the system till clear fluid flows, as recommended in the above article, your system will work as new forever. Use it, if it's not broke; don't fix it.

Synthetic blends are just another way to get into your pocket
They do make a 5.1 that is supposed to be compatible. DOT 5 does not lubricate worth a dam. DOT 5 is OK for static
display cars, that might see a trip around the block.

Why are there so many synthetic blends??........Can you say marketing band wagon
I've known ppl in the automotive publishing business, most are sell outs and will scribe anything for a sell out editor.
Thats a fact! We need the add revenue, so give it good ink....... Ford H.D. DOT 3 is what I use in everything.

 

[Slickone]

So what about DOT 4?

I guess the Ford DOT3 is only at the dealer?