I'm going to my novice DE at Hallett raceway in two weeks, and need to replace my dot 3 with dot 4. I did a search but nothing came up. Everything else on the car is up to specs. Whats the best method to do this? Is it just bleeding the brakes till all the fluid is changed? Do I drain the entire system, then refill and bleed, bleed, bleed?

Thanks in advance, Curt

it's pretty easy if the new stuff is a different color than the old, just bleed, fill, bleed, fill, bleed til the color changes at each corner.

yeah...

buy ATE blue (or gold) and then switch colors every year...

b

Cool. Should the the bleed sequence be backwards? I.E., front left, front right, rear left, rear right? or does it matter?

Thanks Guys.

I used my little vacuum bleeder... sucked out the resevoir, and then sucked out the lines.... add new fluid and bleed...

maybe that was the wrong way... but it worked

I always follow the same bleed sequence and go furthest first... closest last...

if you take the reservoir down half way then you will use less fluid... flush half the fluid out through the caliper so as to get any grit or grime, rather than removing it by turkey baster....

then before the reservoir runs dry you can add the ATE.

I am so Jealous.. I hear AMAZING things from all my friends about hallet.. it is supposed to be a great teener track...

everytime an event comes up for me there, my car is not ready...

b

I've been a volunteer corner worker there for the last two pca club races. A very satisfied customer and friend paid for my DE as a tip for rebuilding his 1.7. I love 914 people.

Thanks for all the tips guys. I just remembered my vacuum guage doubles as a brake bleeder, so this should be easy.

Whoa nellie!!

I wouldnt want any grit or grime flushed through the caliper... I have drained the resevoir all the way down with a turkey baster.... then filled it with clean fluid for fluid flushes...

If the resevoir has some nasty goo in the bottom... you can completely remove the resevoir and clean it well, then replace it, then flush following the usuall procedures..

I bleed the fluid at least once per track event.... and change the fluid yearly... You wont have any grit or grime to contend with if you "maintain" your brake system

I didn't do the "turkey baster" through the calipers... I removed the BRAKE LINE... bigger hole to get crap out of!

I didn't want it through the caliper either...

Ok, We're getting there. I should empty and clean reservoir, remove lines at calipers, flush out lines, reinstall lines to calipers, flush calipers, bleed entire system. Still easy, but definitely longer.

I just did a brake job and installed speedbleeders. They seem to work pretty well but I still have a slightly spongey pedal.

I was thinking that driving it a bit and then rebleeding would cure it.

Any tips and tricks?

A NEAT trick I found when bleeding brakes.
Get a 1pint plastic jar. Place the small plastic tubing, I believe about 3-4mm, about 1 ft long. Place one end of the tubing into the bottle and the other over the drain nipple. The 10mm open end wrench easily accesses the zert and you can drain huge quanities while keeping the floor and paint finish clean. Have fun. But, get the breaks done now so you can hit something at a reasonable speed prior to DE.
L. McChesney

Anthony, If the pedal will "pump up" it's still needs bleeding.

Anthony, sounds like air in the prop valve. That's why everybody hates 'em. Crack the lines on the valve and bleed. You can also tap on it while bleeding to help move the air bubbles to the top.

Yeah, it 'pumps up' a little. I've bled the system quit a bit.

I attended a 4 hour brake seminar a couple of weeks ago and learned a ton. Of particular interest were 2 things: 1. 17mm MC puts out more braking pressure than the 19 mm MC, and 2. Don't use a power bleeder, ie. one that pressurizes the resevoir.
1. Reason is the same reason a spike heel will sink deeper into the lawn than a flat heel. Less surface area with the same amount of pressure from your foot will deliver more PSI to the MC. This revelation came as kind of a surprize considering everyone always wants to "upgrade" to a 19 mm MC but what he says makes sense when you think about it. (By the way, he was the brake expert Grassroots Motorsports consulted for its' 914 racecar project. They had already installed a 19 mm MC on the car before consulting him. He made them put the 17 mm one back on)
2. Reason is that pressurized air in direct contact with the brake fluid forces air molecules into the fluid.

FWIW
The brake guru said vaccuum bleeders were fine to use in his opinion and he was indifferent about speed bleeders.

I think they "outlawed" that type of bleeder... I haven't seen one in years...


the other point... I think that's only valid assumming stock or near stock brakes... the 19mm should still put out more MAXIMUM throughput for big brakes that need it...


true for the same force, you will get less pressure using the 19mm m/c... but that is only a good point until you reach the max output(not pressure... volume) from a 17mm, that is when you need the 19mm

correct me if I'm wrong... I'm not a physicist or a brake specialist, this is just what I've been told...

No, you're right. The 19mm will be able to generate a total of about 25% more pressure than the 17mm one will. But you will have to push much harder to get that pressure--to get the same pressure on each, you have to push 25% harder on the 19mm one than on the 17mm one.

I don't disconnect any of the brake lines when I flush the brake system. I do it just like bleeding the brakes, except that I use my Mity Vac to get almost all of the fluid out of the reservoir first and I re-fill it with fresh fluid. Then go to the right-rear, hook up the Mity Vac, and go until I get none of the old fluid coming out--all fresh. I will usually have to stop and re-fill the reservoir at least once during that process. (If you have upper and lower fittings, use the lower one. If not, no big deal.)

Then I go to the left-rear and repeat. Keep going until all of them have been gone through.

Then I go fetch an assistant and do the two-man push-the-pedal bleeding process, just to make sure that all the air is out.

--DD

Some place there is that 17mm vs 19mm physics article. I think on PP.
L. McChesney

25% harder for equal pressure. So to actually get 25% MORE pressure you'd have to push twice as hard, right?
100% more pushing for 25% more pressure

Geez guy's, I just want to change the fluid, not upgrade the brakes. My brakes stop great. Meanwhile, I've been busy dodging tornadic storms and hail. Hot times in T-town tonight.

Dave, I have the mighty vac setup.

So it's another evening drive in T-town along the Arkansa river with the Targa top on. When you say that, I can still recall the smell of coal oil lamps in my grandmother's cellar in Owasso.
L. McChesney

Coal Oil? Man, you must be older than dirt . I'm a city boy.

Just kidding, went through a few thunderstorms at my grandpa's farm in the early fifties. We all ran to a community storm cellar "down a the road a peice". It was lit by candles. Scared the shit out of a 5 year old.

BTW, the river's not a good drive anymore. Joggers, walkers, skaters, and the people who prey on them, and LOT'S of red lights. Osage Hills has all the good 914 roads close by.

Best investment you'll make in your brakes is a set of Speed Bleeder screws. They have a small check-valve in them, to prevent air from reentering the system during bleeding.

I've installed them in two 914s and my Wrangler. They're money.

-Rusty

don't forget to put the speed bleeders in the top fitting on the calipers.

kevin

What is the best procedure for flushing out silicone fluid?
Thanks
Van914

I like to drain the calipers where possible, as soon as fresh fluid comes out of the bleeders. My reasoning is this: first flush the lines, then get rid of all the old fluid before refilling with fresh fluid.

After rebuilding a lot of calipers I puzzled over the extra dirt and corrosion in the outer halves. Then I figured out that a normal bleed rarely changes the fluid in the outer half. If you look at the caliper, the bleed is directly above supply line. The fluid flow is from the line across the back of the piston, up the channel and out the bleed nipple. Nowhere in there do I say anything about fluid flowing into the piston and changing the fluid there, nor do I say anything about fluid flowing to the outer half of the caliper. The fluid does not flow there because it is not forced to do so, and takes the easiest path from inlet to outlet.

True that this procedure makes bleeding much more difficult and requires more fluid, however I cannot come up with a better way to change ALL the fluid. This is particularly true for the rear calipers with the adjustment mechanism built into the piston. Comments????

I was concerned about that, too, when I was changing the 10+ year old brake sludge in the /6 after I dragged it out of the barn.

I changed the fluid and the leaking MC. Drove it around for a day or so. Changed it again. A week later, I changed it again.

My thoughts were that all the brake fluid would eventually mix together, especially after some spirited driving when I got my brakes hot. No problems, and the brake fluid was clear when I changed it again 9 months later.

Van, I've heard ugly things about silicone fluid in standard brake systems. I have no personal experience, but was told that I would need to change out all the rubber in the system, because the silicone based fluid would degrade it over time. Maybe it's urban legend... can someone shed some light on that?

-Rusty

On that issue with the power or pressure bleeders-IE the popular motive prod. pump pressure bleeder,

-if you follow the directions and dont pressurize the system very high, you cant get pump air into the brake fluid. In fact, I'm pretty sure that there is no way that you'd be able to put enough pressure using a pump to do this. My guess is that the brake GuRu that was saying this, just isn't familiar with bleeding by this method, anyway, everyone has their own preference and there's many ways to do it properly..

BTW, I agree, the speedbleeder's are very good-and since the origional bleed nipples are usually rusted to hell, they're a good upgrade for cheap$$

Ok, so my teener has been sitting for the last 12 years. Fluid needs to be purged and replaced, no question (among other stuff). How about the condition of the hard brake lines? Is there any way to ascertain their condition, or would it be best to replace them all (after all, can't look inside for rust problem spots)?

Andy

You can start by bleeding the system. If the color of the fluid is too dark, then I'd replace all the lines, both metal and rubber.

Lot of different things going on in this thread.
A 17 m/c will have more fluid pressure than a 19 m/c if you apply the same force on the brake pedal. You generally only have to increase the size of the m/c if you enlarge the caliplers. Bigger calipers will have bigger pistons so you need the increased fluid volume to move the pistons.
I'm not sure the force on the pedal would be increased by 25% to get the same fluid pressure. The brake pedal arm acts like a lever on the piston in the m/c and I believe there is a 4 to 1 ratio.
I've got a Girling dual m/c setup with large Wilwood calipers. The Girling works fine except it has a little tiny (maybe 2 oz) reservoir on each m/c. I use a Motive power bleeder with no problems. Hard to believe that 8-10# pressure would contaminate the brake fluid with air.
andys, with your car sitting for 10 years you want to go completely thru the brakes. Think you should plan on rebuilding calipers, new pads, new rubber hoses. You'll have a better idea of what condition the metal brake lines are in after you pull the calipers apart and look inside the rubber lines.

Sitting for 12 years? Change the rubber lines, flush/bleed the system and see how it stops. I wouldn't mess with the hard lines unless you had to for some reason (concours restoration, broke an end off R&Ring a caliper, etc).

Flush and bleed the system a couple of times with elCheapo FLAPS brake fluid, then after you're sure it's good, replace with ATE or your favorite high performance fluid. ATE is just too expensive to just flush through a system for simply cleaning, IMHO. But then, I'm cheap.

My calipers didn't need rebuilding after sitting for 10+ years, but I decided to do it a couple years later... so I could really clean the whole area up, powdercoat calipers, etc.

Depending on the condition of the rotors/pads, you could have them turned to knock off imperfections have install new pads. If it's just light surface rust - don't bother. It'll be gone by the second stop.

Q: Can you recycle brake fluid along with motor oil?

I know if you mix the brake fluid it will eat your seals. We had a truck at work, the mecanial services topped up the brake fluid with the wrong type. The rubber gasket in the MC grew to about 3X it's normal size and was like a sponge...Truck was gone for a week while they replaced all the seals.

Well, I got my brake fliud flushed with the mighty-vac. Piece of cake. Nasty, dirty fluid out, clean fluid in. Thanks for the info guys.

How do you do it with the mity vac? Is there a special fitting you need to buy?

Nope, just the stuff that came with the unit.

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Sitting for 12 years? Change the rubber lines, flush/bleed the system and see how it stops. I wouldn't mess with the hard lines unless you had to for some reason (concours restoration, broke an end off R&Ring a caliper, etc).
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andys, with your car sitting for 10 years you want to go completely thru the brakes. Think you should plan on rebuilding calipers, new pads, new rubber hoses. You'll have a better idea of what condition the metal brake lines are in after you pull the calipers apart and look inside the rubber lines.
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Guys, the car already has stainless flex lines installed by the PO. Since brake fluid absorbs moisture, I'm concerned about the hard lines rusted somewhere on the inside. Don't know any way to ascertain their integrity. That said, honestly I've never seen an instance where this occurred, even on very old vehicles (my '56 F100 w/ SBF V8 had the original hard lines. Same w/ my '47 Ford).

Andy

I'm sure that someone will correct me if I'm wrong... but stainless lhoses are still rubber on the inside. The rubber swells (to the inside) with age. Stainless braided hoses need to be replaced at approximately the same interval as their OEM counterparts.

They're cheap insurance. It's your brake system, though.

-Rusty

I think the SS ones are usually teflon lined.

Just found out about speed bleeders from a 914 owner on a benz bbs.
Didn't see the site posted so...

http://www.speedbleeder.com

FWIW, they are cheaper at Pelican Parts.

I think I got mine at Paragon.

I got my last set (for my Wrangler) direct from the company themselves... They were such nice people to talk to on the phone.

When they didn't have a specific listing for the front (or rear, I forget) for my year Wrangler, they sent me several sets to try (on the honor system that I would return the unused ones.)

Good product, great people. I'll give them the few extra bucks and order direct for that kind of service.

-Rusty

I did a couple of web searches and noticed that there is two brands of speed bleeders.

Russell Speed Bleeders:

http://www.russellperformance.com/motorcyc...ed_bleeders.htm


The other one are found at speedbleeder.com. Has anyone use the Russell speed bleeders?

Lawrence, I know the lines are plastic on the inside, guess they could be teflon.
I belong to the "Don't Fix It If It Ain't Broke School".
I think the stainless line sets came from someone seeing them on a race car. Race car teams do a lot of stuff to their cars to eliminate problems. Probably some driver did a off course and cut up a rubber line, the engineer said I can fix that!
On race cars everything gets inspected and parts are routinely replaced including flexible stainless brake lines.
Your car will not stop any better with flexible stainless lines than it will with good OE rubber lines. If anyone had a brake problem and replaced the rubber lines with stainless and the problem went away there may have been 2 problems. Either the existing rubber lines was 30 yrs old and so deteriorated they would not pass brake fluid or the fluid had so much air/water in it that the brakes didn't work properly.
When you have rubber lines you can see if they're swollen, kinked, cut, or leaking. You cannot always tell what is going on with the stainless lines.
OTOH on the street someone may see the stainless lines and that makes them priceless.

Ahhh... the "bling" factor on the street.

Thanks for the information. I'm always happy to learn something new. I also agree with your assessment of the equality of the types of lines.

I use (and am happy with) OE rubber lines. They have always served me well, and I've never had one fail.

-Rusty