Clutch and Brake Fluid


MDT

GT Owner
Jun 24, 2006
209
Had a problem on track with the clutch pedal going soft. I have heard that the line passes too close to something hot, not really sure. The brakes were fine, but then I wasn't pushing all that hard. In all my searches a lot of people are using the stock Ford DOT 3 fluid. Apparently the Ford DOT 4 has been discontinued. I'm all for stock, but since it failed, seems I should use the Kendal Super Blue? I'm not planning on tracking a lot, so is this fluid stable or does it need to be changed often even if not on track? Thanks for the help.
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,177
We have been using Motul 600 and with very good results.
 

BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
Shadowman and Shadow Boy came by for a visit and the Shadowman brought some Motul 600 to bleed my clutch. I did the open/close routine while Shadowman did the press/release routine. The clutch line is next to the exhaust so that could be causing a problem for some.

I decided to go with ATE super blue and 200 for brakes and will try the Motive pressure bleeder by myself. The boiling point of the ATE isn't quite as good as the Motul but it has the advantage of different colors so that you know when the entire line is flushed and it cost a bit less too.

After reading this maybe I shouldn't use the Motive :(

http://www.stoptech.com/tech_info/wp_brakefluid_1a.shtml



Brake Fluid Dry Boiling Point Wet Boiling Point Suggested List Price
AP SUPER 600 590°F 410°F $18.00/16.9oz. .
CASTROL SRF 590°F 518°F $69.99/33.8oz.
NEO SUPER DOT 610 610°F 421°F $15.00/12oz.
MOTUL RACING 600 593°F 420°F $15.00/16.9oz.
MOTUL DOT 5.1 509°F 365°F $6.50/16.9oz.
ATE SUPER BLUE 536°F 392°F $11.99/33.8oz
VALVOLINE SYNPOWER 503°F 343°F $4.97/16.9oz.
ATE SL 500°F 329°F $7.95/16.9oz.
CASTROL LMA 450°F 311°F $3.50/16.9oz.
AP 551 528°F 288°F $12.50/16.9oz.
 
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fjpikul

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Jan 4, 2006
11,475
Belleville, IL
The clutch has two bleeding points, one on the engine side of the firewall in about the middle, and a second down low, passenger side near the exhaust. Don't do this when the engine is warm.
 

Lorenzo

GT Owner
Mark II Lifetime
Dec 28, 2008
626
U.S.A.
http://www.stoptech.com/tech_info/wp...fluid_1a.shtml

great information Thanks Blackice!!
 

MAD IN NC

Proud Owner/ BOD blah bla
Mark IV Lifetime
Feb 14, 2006
4,211
North Carolina
in lieu of the NEO SUPER DOT 610 610°F 421°F $15.00/12oz. ?
 

AJK

GT Owner
Mark II Lifetime
Jul 12, 2006
335
Shadowman and Shadow Boy came by for a visit and the Shadowman brought some Motul 600 to bleed my clutch. I did the open/close routine while Shadowman did the press/release routine. The clutch line is next to the exhaust so that could be causing a problem for some.

I decided to go with ATE super blue and 200 for brakes and will try the Motive pressure bleeder by myself. The boiling point of the ATE isn't quite as good as the Motul but it has the advantage of different colors so that you know when the entire line is flushed and it cost a bit less too.

After reading this maybe I shouldn't use the Motive :(

http://www.stoptech.com/tech_info/wp_brakefluid_1a.shtml



Brake Fluid Dry Boiling Point Wet Boiling Point Suggested List Price
AP SUPER 600 590°F 410°F $18.00/16.9oz. .
CASTROL SRF 590°F 518°F $69.99/33.8oz.
NEO SUPER DOT 610 610°F 421°F $15.00/12oz.
MOTUL RACING 600 593°F 420°F $15.00/16.9oz.
MOTUL DOT 5.1 509°F 365°F $6.50/16.9oz.
ATE SUPER BLUE 536°F 392°F $11.99/33.8oz
VALVOLINE SYNPOWER 503°F 343°F $4.97/16.9oz.
ATE SL 500°F 329°F $7.95/16.9oz.
CASTROL LMA 450°F 311°F $3.50/16.9oz.
AP 551 528°F 288°F $12.50/16.9oz.

My father has used the Motive on my GT and Porsches, BMW, and other Ford vehicles with good results. No lack of good pedal or other air in the line issues. He tries to keep the pressure between 15 and 18 psi. He has also used a vacuum pump before he got the Motive but found that it sometimes appears that there is air in the line when it is leakage around the bleeder. He doesn't like using the pump the brake pedal as this requires the internals to function beyond their normal working zone. Clutch OK to pump as full travel is normal.
 

kmillen

Well-known member
Jan 29, 2007
504
We have been playing with different fluids for many, many years and hands down the AP fluid is the best. Not only because of the fact it has the highest boiling point, but also because of its recovery rate. Once you boil the fluid, you lose pressure. The fluid will recover some of its pressure after it cools, however it will never come back to 100%. The AP fluid comes back to about 90% of its dry, original pressure while most other fluids only come back about 75%. This information comes to us from the NASCAR drivers currently using AP Racing fluid, and comparing it to some of the other fluids they use like the Castrol SRF.

Motul RBF600 is a decent fluid, however I would not put it in anything I intend on tracking seriously. We used to use RBF600 in our track cars, but that's because at the time it was the best. After running and boiling the RBF in our GT on the 2006 rally Steve came back home and said "Take that XXXX out of all of the cars, we need to go test other options." During the rally we replaced the RBF600 with some Castrol SRF. The SRF was much better than the Motual however it was very expensive. Fortunately, we are the North American distributor for AP Racing so we contacted them to see what they offered. They came back with the fluid they were using with the NASCAR race teams and we have been running that in everything, ever since. Not only does the AP fluid have the highest boiling point, it also has the best recovery, and on top of that, it's pretty affordable in comparison to some of the other racing hydraulic fluids out there.
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,177
A lot of different factors here. If I was building a purpose built track car or a "street" car that spent most of it's time on the track, I'd probably look/experiment with many alternatives. However for a largely street-driven car that sees occasional track time, a high quality, readily available fluid like Motul 600 is a great choice.
 

BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
A lot of different factors here. If I was building a purpose built track car or a "street" car that spent most of it's time on the track, I'd probably look/experiment with many alternatives. However for a largely street-driven car that sees occasional track time, a high quality, readily available fluid like Motul 600 is a great choice.

Both Kendall and Kyle have valid points. It really depends on how aggressively you are going to use your brakes.

e.g.

1. If you drive like EP you can use Gunk, Prestone, or anything.
2. If you always drive on the public roads and never brake the laws you can do the same as #1.
3. If you drive on the track get something better. Look at the list. You can start with AP and know that it is probably the best or go with one of the others believing that you will not hit the limit.

Note that having fresh fluid is just as important as what type of fluid. I much rather have fresh VALVOLINE SYNPOWER than old AP fluid. I used to use VALVOLINE SYNPOWER but it is no longer sold.
 

KMCBOSS

RED GT owner
Mark II Lifetime
Dec 3, 2006
995
Bremerton, Washington
Another issue I found was the original fluid turning to jell. I fall into catagory #2 above but I had clutch issues (clutch wouldn't fully release causing the engine to stall at stop lights) last year and upon inspection of the clutch master cylinder I found the fluid was turning to jell (thought I had a slug in the master cylinder).
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,177
I found the fluid was turning to jell (thought I had a slug in the master cylinder).

Wow, we just replaced (upgraded) a clutch in a GT and when we flushed and re-filled the clutch fluid, we too found some snot-balls of gel. Definitely something to keep an eye on.
 

Fubar

Totally ****** Up
Mark II Lifetime
Le Mans 2010 Supporter
Aug 2, 2006
3,979
Dallas, TX
Well, I guess I need to run some new fluid thru the old girl. I'm pretty good about doing the brake fluid after any type of track day, but I've never done the clutch. Looking at the numbers, SRF is the best stuff (and if its my ass on the line, I'll spend x4 price on fluid) but I have never heard the term "recovery" when discussing brake/clutch fluids. I presume this means the time it take a gas bubble to return to liquid form. Which would simply be the time it take to expunge the heat from the fluid. Are some fluids more conductive than others (and wouldn't that make them heat up faster)?

What causes a fluid to jell? Are some fluid more susceptible to this than others? SRF has such a fantastic wet boiling point that I am not concerned with its moisture content (from a boiling standpoint) but is the moisture the contributing factor on the "snot balls?"
 

kmillen

Well-known member
Jan 29, 2007
504
Recovery rate refers to the brake fluids ability to return to its original compressability. Pretty sure I just made that word up.

When brake fluid is new you have 100% compressability, and best performance. This feeling will be the same for all of the major fluids. However, once that fluid is boiled, it's done. It loses some of its "compressability" meaning the pedal becomes spongey and won't come back until you flush the fluid out of the system. The big difference between AP fluid and most other fluids is that recovery rate. The AP fluid comes back to about 90% once it cools down, where Castrol SRF only comes back about 75%. You will never get 100% back after the fluid has been boiled. Once you boil the fluid, flush it out.

A lot of people only associate a spongey pedal with air in the lines. Without question the majority of soft or spongey brake pedals are caused by air in the lines. However, boiled brake fluid also displays similar characteristics and when bled may not have any air in the line, yet the pedal comes back. It's because you've replaced the spent fluid with fresh fluid which still has 100% of it's compression.

There are three different AP fluids available:
http://www.stillen.com/product.asp?id=APRBF01&c=BR&m=all

APUltra is a good affordable fluid that would work very well for a car that will only see street use and occasional, LIGHT, track duty.
AP600 is a good fluid that you could feel confident running in most street cars being used on a race track.
AP608 is the top shelf stuff. This is the fluid that the NASCAR teams run when they're at the most demanding tracks like Sears Point, Watkins Glen, Bristol. etc.

Like Kendal said, Motul RBF fluid is readily available at most automotive stores. It's widely used and can be found in a pinch. However, I would not put it in the same category as the AP or Castrol SRF race fluids.

I spoke with Rocketman last night about the Super blue fluid and he asked me about our experience with it. I informed him I should have made a post on the forum but we do not have any first hand experience with this fluid. The AP fluid exceeded all of our expectations so once we found it, we stuck with it.
 

Kingman

GT Owner
Mark II Lifetime
Aug 11, 2006
4,072
Surf City, USA
Are you guys saying that you are using the same fluid for the clutch as you do for your brakes?
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,177
Are you guys saying that you are using the same fluid for the clutch as you do for your brakes?

Absolutely! Also use the same stuff for the blinker fluid when low.
 

Kingman

GT Owner
Mark II Lifetime
Aug 11, 2006
4,072
Surf City, USA
Absolutely! Also use the same stuff for the blinker fluid when low.

I give up. Blinker fluid???? What pray tell is that?

I have a feeling it is the same thing as a Left-handed smoke bender I had to go chase down in Boy Scouts.....once.
 
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nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,177
Yeah, you got it. So you had the left-handed smoke bender.... I had "snipe hunting". I'm slow learner, I went twice.

But I'm the brainiac of the family (it's all relative). I still remember my dad telling my older sister to be sure to have the guy change the air in her tires when she went in for a service. She came back embrassed and a little bit mad!
 

MDT

GT Owner
Jun 24, 2006
209
Actually now they do change the air in your tires, and charge for it too....
 

BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
Actually now they do change the air in your tires, and charge for it too....

You mean the nitrogen scam getting traction, after the Nigerian scam becomes more widely known.