bleeding brakes

I was wondering if it is a hard and fast rule to bleed brakes after every race weekend?
I run the motul 600 and just completed a double school at CMP. It was very cold all weekend and the brakes never showed any sign of fade or mushyness all weekend.
After my first school, in 100 deg. temps, at moroso I bled the brakes and saw no bubbles and the fluid was very clean.
This stuff is expensive, so if I dont have to...
My car is also very light and has pretty big disc's, if that makes a difference...
matt

What rule? When I race my Capri at Laguna Seca, I have to bleed and adjust my drum brakes after nearly every session if I push the car. With my VW, I've run several weekends between brake maintenance.

It depends.

just asking.
I've been told by a few different people that it is something you do before every race weekend...

It's not a bad idea to bleed as part of the prep, and a good flushing is important, esp in humid climates, but if you don't have to bleed after a session, then don't.

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Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

I try to bleed pre-race weekend but do not do it during a race weekend unless absolutely necessary (like changing a caliper or wheel cylinder).

Cheers.

Matt, brake fluid only really wears out when it's boiled. Like all of the rest have said, brake bleeding, is like changing oil. Setup some standard maintenance schedule that's comfortable with your finances, and stick to it.

Like Joe said, the VW's have pretty good brakes, and I normally bleed the front's during a race weekend just to get fresh fluid in the calipers.

I also use Motul 600 and normally go through a bottle a year as part of "normal maintenance"



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Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html

I bleed before every session. Brakes are too important to me. I want to know if there are issues. The other part of that is knowing that stuff is fresh I feel allows me to have that little extra edge when I need it.

Ok, well that answers it for me. I'll wait until after CMP in feb. and just see how they feel. Try going to two weekends or maybe more...
matt

I don't know if there's something wrong with me or my car, but I just ran a whole season (5 weekends) without touching my brakes. I typically drive deeper into corners than my competitors and don't have any brake cooling beyond stock, and I've never had a hint of fade. Might be that the tracks I've run are really easy on brakes - Grattan, Gingerman, and MidOhio. I've been warned that things are likely to change if I venture to Blackhawk Farms.

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Marty Doane
ITS RX-7 #13
CenDiv WMR

Marty, I'm with you. If it gives someone a mental edge, then that is great. But it certainly is not necessary, esp. with IT cars.

I bring a can of brake fluid with me to each race and if I start to question anything, I'll change it before the scheduled time. As for brake fluid, I have been very, very happy with ATE's race fluid. And it costs less then $15 for a can that lasts me the entire season. As with most brake fluids, they make it in two different colors to make flushing it easy. (Boiling point 536 degrees F; Wet boiling point 392 degrees F)

Matt, it's all about who you ask. If you ask people how often everyone changes their oil, you'll get just as diverse answers.

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Dave Gran
NER ITB #13
'87 Honda Prelude si

yep, I can see that. I will just feel it out and see what happens, always being prepared to do it at the track if I have to.
I bought the power bleeder from Motive. Used it for the first time and seemed to work fine without having to go bug the wife...
thx for the info guys.
matt

I bleed:
1. When I have an inkling of any braking problem.
2. Before enduros
3. Before Big races (ARRC)
4. Once a year I change the fluid out. Usually I do this at the ARRC, which takes care of 3.

Lets face it, we never want to lose a race, or have to come in early, or heaven forbid, Crash, if we can avoid it.

Also, some cars are harder on the fluid than others. Such as cars with non vented rotors or cars that don't duct air to the caliper/rotor.

Also, I heard it is a good idea to bleed fluild when you change pads, rather than just just force old crappy fluid back into the system. I have not decided on this one yet.

Completely dependant on tracks for me.
Like Alan, I also do it before any major events. (schools, thus far)

Marcus

Before major events for me, usually twice a year, but I don't use the expensive fluid...Castrol LMA....the last time I bought it was 1.75/pint. Have never had brake problems.

One other thing, KD tools makes a vacuum brake bleeder that is killer. You need an air compressor to use, but when I filled my new car after blowing out the lines with compressed air, I was able to fill/bleed the complete system by myself in less than 30 minutes.

good luck, Chuck

Bleeding can accomplish many things, and each racer (also type of car) will be somewhat different. Many people bleed to ward off the hygroscopic characteristics of standard brake fluid. Yes, although the recommended changing cycle for street cars is one year, moisture can be absorbed into the system thru the seals themselves in a progressive fashion during that time. Moisture is CONSTANTLY being absorbed, so length of time in the system is important. That alone might make one want fresh fluid every new time out (race weekend).

Others have heat issues that necessitate changing just to replace the "fried" fluid after sessions, or races. Certainly, if one has obvious air-in-the-line issues during a race, flushing/purging will be the order of the day.

Others will change it due to nervousness about having absolutely the "best they can be" even if "it ain't broke".

Establish a program that meets your needs, and stick to it. Remember, fluid out of a container that has been opened for a while is not "fresh", and will have already been contaminated with moisture. Small cans are the best.

Good racing.

Bill

[This message has been edited by bill f (edited January 31, 2005).]

Quote:

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Originally posted by Joe Harlan:
I bleed before every session. Brakes are too important to me. I want to know if there are issues. The other part of that is knowing that stuff is fresh I feel allows me to have that little extra edge when I need it.

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Funny, same goals different approach.

I bleed mine before every weekend and then don't touch them at the track (unless I have to) for the exact same reasons. Things happen and the fewer things I fiddle with between sessions the less likely I might dork something up.

We had a similar discussion on the Waterford Hills site (see link) http://www.waterfordhills.com/phpBB2/viewt...opic.php?t=3839

Lot's of engineering minded racers at our track so there was some interesting data posted along with opinions.

The conclusions that I made for my team is to bleed just between race weekends. I'm driving a light ITC Honda Civic and only use the brakes twice on the entire track. That's only 80 pushes of the pedal in a weekend.

I have a follow-on brake fluid question. I use motul 600 as well and use a pressure bleed system to bleed the brakes. This pressure pot system works great. The only drawback is it can waste a bit more fluid than using individual bottles.

My normal routine is to dump out the remaining fluid at the end of each season. Depending on where I fall in cycle of bleeding for the season this could be as much as 2 quarts or so. Usually closer to 1-1.5 quarts.

With the pressure pot system I try to minimize the amount of fluid I put in the pot at any given time. But you need to have enough to cover the bottom of the pot and then a little higher so the pick-up tube can get the fluid up. On the other hand if I'm bleeding during a race weekend I want enough fluid in there so I don't run dry while bleeding #3 wheel out of 4 to be done.

I'm wondering if it is overkill to dump this fluid at the end of each season. The pot itself is pretty much a sealed container. But I have of course exposed the fluid to the atmosphere when I opened the bottles and dumped them in.

When I have asked this question in the past I got the usual line of "dump the fluid, it's only 2 quarts" "brakes are important" "what is your life worth" yada yada yada...

I'm looking for a technical answer here. What specific attribute(s) of the fluid make the fluid "bad"? Is it moisture content alone? Assuming the fluid has not been boiled?

If that's the case why couldn't I use a moisture meter (for brake fluid) and measure the moisture content at the beginning of the new season to see if the fluid in the pot is "truly" "bad"?

Thanks
Wayne

What about taping a desiccant packet to the lid inside the container. That should remove any water moisture...wouldn't you think?

How'd they get the fluid from the BIG container into the little Liter/Quart bottles without exposing it to moisture?

Golfs seem to be pretty easy on brakes but I'm still using the Ford HD fluid that I first learned about from Smith's book 20 years ago. We used to buy it by the case of small bottles and use it in both the race cars and the tow vehicles.

It's cheap, readily available (no shipping $ and you can score it in a hurry if you run out), it's as temperature-tolerant as many "racing" fluids, and it isn't as hygroscopic as most - because it's not assumed that it will get thrown out every half hour. If nothing else, it's good to know about so you have an option if you get in a bind while traveling.

Ford has given it a new number PA-1 - to replace the old CAZ... designation.

From this, you can accurately infer that I don't bust my hump bleeding brakes. Typically once before a race weekend...

K

We bleed them before every track weekend, with every pad change, and whenever we suspect a problem (like boiling the crap out of a caliper or two). We only flush them once a year or so.

It's gonna be interesting to see how a Baby Grand does on brakes compared to the RX-7. :-)

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Doug "Lefty" Franklin
NutDriver Racing
ITA/IT7 Gen1 RX-7
SEDiv/AtlRegion