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#2417455 - 12/12/17 02:26 PM Re: Talk me out of DOT 5 brake fluid? [Re: GoodysGotaCuda]
MoparCar Offline
member

Registered: 07/21/05
Posts: 119
Loc: Colorado
Originally Posted By GoodysGotaCuda
For what it's worth, for street use I haven't had any issues with the DOT5, but it's also only been 1,500 miles.

....the Wildwood pad knockback, however, is a different story.



Goody,
Is that knock back on fronts, rears or both?

Thanks, Wes

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#2417672 - 12/12/17 08:32 PM Re: Talk me out of DOT 5 brake fluid? [Re: MoparCar]
GoodysGotaCuda Online   work
5.7L Hemi, 6spd

Registered: 11/23/04
Posts: 24103
Loc: Texas
Originally Posted By MoparCar
Originally Posted By GoodysGotaCuda
For what it's worth, for street use I haven't had any issues with the DOT5, but it's also only been 1,500 miles.

....the Wildwood pad knockback, however, is a different story.



Goody,
Is that knock back on fronts, rears or both?

Thanks, Wes


Haven't quite determined that just yet.
_________________________
1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - Build page -> https://www.facebook.com/GoodysGotaHemi<-
1976 Dodge Warlock - "Her Truck" - 360/727 2wd
2016 BMW X1
2016 Subaru WRX

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#2417676 - 12/12/17 08:42 PM Re: Talk me out of DOT 5 brake fluid? [Re: GoodysGotaCuda]
goldduster318 Offline
pro stock

Registered: 01/19/03
Posts: 1409
Loc: Lake Orion, MI


Originally Posted By John_Kunkel
Originally Posted By goldduster318
. I am not aware of any OEM vehicle that comes with DOT5.


Avanti, Harley Davidson, probably some exotics.


If there is any ABS/ESC on these vehicles (which is required on USA sold cars since 2011), I can pretty much assure you they aren't using DOT5 silicone brake fluid as I'm not aware of any supplier that allows it. I worked at 2 of the 6 major companies that sell these systems. DOT5.1, they allow but I don't consider that to be very different than DOT4.

Originally Posted By Supercuda
Dot 5 or Dot 5.1?

Dot 5 isn't compatible with ABS systems so I doubt any OEM is using it.

5.1 is NOT silicone based.


Thank you, I believe you are correct.

Originally Posted By GoodysGotaCuda
For what it's worth, for street use I haven't had any issues with the DOT5, but it's also only been 1,500 miles.

....the Wilwood pad knockback, however, is a different story.


What's your rotor runout? If they are the two piece hub type, perhaps you can re-clock the rotor on the hub to help it. IMO over 40 micron is too much on anything near a new condition.

also from wilwood's own site:
http://www.wilwood.com/TechTip/TechBrakeFluidTip.aspx

Quote:
Wilwood does not recommend using DOT 5 fluid in any racing applications. DOT 5 fluid is not hygroscopic, so as moisture enters the system, it is not absorbed by the fluid, and results in beads of moisture moving through the brake line, collecting in the calipers. It is not uncommon to have caliper temperatures exceed 200 degrees F, and at 212 degrees F, this collected moisture will boil causing vapor lock and system failure. Additionally, DOT 5 fluid is highly compressible due to aeration and foaming under normal braking conditions, providing a spongy brake feel.
_________________________
'70 Duster 470hp 340/A-833/8 3/4 3.23 Sure-Grip

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#2418206 - 12/13/17 08:04 PM Re: Talk me out of DOT 5 brake fluid? [Re: GoodysGotaCuda]
SportF Offline
super stock

Registered: 01/08/08
Posts: 740
Loc: Minn
Gosh, I just love this topic. And I always did.

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#2418377 - 12/14/17 07:28 AM Re: Talk me out of DOT 5 brake fluid? [Re: goldduster318]
GoodysGotaCuda Online   work
5.7L Hemi, 6spd

Registered: 11/23/04
Posts: 24103
Loc: Texas
Originally Posted By goldduster318


What's your rotor runout? If they are the two piece hub type, perhaps you can re-clock the rotor on the hub to help it. IMO over 40 micron is too much on anything near a new condition.


Haven't bothered measuring runout as it only appears after a decent turn. I suspect it's more of a dynamic problem. I will be investigating a residual valve, which has been recommended across a few resources I have come across.

Quote:

also from wilwood's own site:
http://www.wilwood.com/TechTip/TechBrakeFluidTip.aspx

[quote]Wilwood does not recommend using DOT 5 fluid in any racing applications. DOT 5 fluid is not hygroscopic, so as moisture enters the system, it is not absorbed by the fluid, and results in beads of moisture moving through the brake line, collecting in the calipers. It is not uncommon to have caliper temperatures exceed 200 degrees F, and at 212 degrees F, this collected moisture will boil causing vapor lock and system failure. Additionally, DOT 5 fluid is highly compressible due to aeration and foaming under normal braking conditions, providing a spongy brake feel.


Understood. When I consider racing the car, I will flush out the DOT5. Until then, I have had no issues with as aggressive of street braking as I can get.
_________________________
1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - Build page -> https://www.facebook.com/GoodysGotaHemi<-
1976 Dodge Warlock - "Her Truck" - 360/727 2wd
2016 BMW X1
2016 Subaru WRX

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#2451097 - 02/13/18 05:37 AM Re: Talk me out of DOT 5 brake fluid? [Re: GoodysGotaCuda]
Dilbert Offline
top fuel

Registered: 08/21/03
Posts: 2281
Loc: out riding & passing you
pad knock back is typically from loose wheel bearings...how did you set up the wheel bearings?
...and dot 5 in a track type street car is amusing...


Edited by Dilbert (02/13/18 05:38 AM)

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#2452400 - 02/15/18 10:07 PM Re: Talk me out of DOT 5 brake fluid? [Re: Dilbert]
GoodysGotaCuda Online   work
5.7L Hemi, 6spd

Registered: 11/23/04
Posts: 24103
Loc: Texas
Originally Posted By Dilbert
pad knock back is typically from loose wheel bearings...how did you set up the wheel bearings?
...and dot 5 in a track type street car is amusing...


Wheel bearings were setup to factory spec, actually tightened slightly, no improvement. Rears are green bearings, as required with the Wilwoods.
_________________________
1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - Build page -> https://www.facebook.com/GoodysGotaHemi<-
1976 Dodge Warlock - "Her Truck" - 360/727 2wd
2016 BMW X1
2016 Subaru WRX

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#2453751 - 02/18/18 10:38 PM Re: Talk me out of DOT 5 brake fluid? [Re: GoodysGotaCuda]
469runner Offline
super stock

Registered: 01/07/04
Posts: 1061
Loc: Virginia
My friend in the Army that is a heavy vehicle mechanic says all the vehicles they service run DOT 5 fluid.

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#2453791 - Yesterday at 01:15 AM Re: Talk me out of DOT 5 brake fluid? [Re: 469runner]
Mattax Offline
super stock

Registered: 02/28/10
Posts: 982
Loc: Phila. Pa.
Originally Posted By 469runner
My friend in the Army that is a heavy vehicle mechanic says all the vehicles they service run DOT 5 fluid.
That would correspond with the Army Report I cited (and linked) on the previous page.

All of these fluids have an application.

Some people assume that posts in this subforum are oriented toward racing, and on the other side, there are a few who don't have clue that some people are here because they are very interested in high performance driving and racing. Otherwise the pros and cons seem to be outlined pretty well. Both silicon and non-silicone have their place.

Whichever you choose, it will depend on the intended uses and priorities.



Edited by Mattax (Yesterday at 01:19 AM)

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