Dot 4 or Dot 5.1

[Joel]

In a couple of weeks I'm going to flush thru my brake system. I dont want to use silicone fluid due to the difficulty of bleeding, and I don't want to use racing fluid due to its affinity for absorbing moisture(supposed to be worse than dot4).I have thought about using Dot 5.1. Has anyone used it? I sell it to some track day racers in my shop and I've never had any complaints but I don't have any specs for it. Any opinions and is it sold in the states? I believe silicone fluid is designated DOT 5

 

[Nadine UK GTS]

Don't use silicon!

I use Castrol SRF, expensive but high wet and dry boiling point, doesn't absorb as much moisture as some others in our damp climate.

When bleeding, best to pressure bleed. I got a second master cylinder fluid cap and drilled into the top of it to fix pressure bleeder, (this arrangement did leak however under pressure). There is a Chrysler "special tool" for pressure bleeding, but, in the UK they were unable to obtain it for me. How do you guys pressure bleed out there, ie, how to you fix / seal onto the master cylinder reservoir?

 

[ruckdr]

Loel,
Try these sites: http://yourkovich.com/brkfluid.htm http://www.vtr.org/maintain/brake-fluids.html http://www.fairdesigns.com/tpp/misc/brakes.html

 

[JonB]

Joel.........there was an excellent and lengthy discussion here recently: Search "Motul"

You have nothing to fear from Dot-4 racing varieties....nor from DOT 5.1. Nor from Dot-4 non racing varieties for that matter. The 5.1 is more "stable" at age than racing DOT-4s, but no worries either way. If you plan to ever have hot brakes/track events and/or drive like Nadine (!) go with racing hi-temp fluid.

Do NOT USE SILICONE

 

[99t1]

AP Racing 600 has worked well for me, see AP Racing

 

[Tom and Vipers]

The info from Baer refers to

Ford High Performance DOT 3 Brake Fluid

and NOT Ford Super DOT 4 Brake Fluid.

I thought the Super DOT 4 was the "good" Ford fluid?

 

[ruckdr]

Tom,
Yes, you mentioned the Super Dot 4 Ford fluid in another post, and I contacted Ford, and they could not come up with it or a part number. I also searched the web, including the sites listed above, but could not find it.
The High Performance Dot 3 part number is PM-1.
Later,

 

[Tom and Vipers]

I just bot 2 16oz bottles and am holding one in my hand now. It is entitled: "Super DOT 4 Motor Vehicle Brake Fluid For Use With Ford Focus."

The Part Number is YS4Z-19542-AA FIR No. 114105

Actually the instructions/application listed on the back is quite bizarre:

"For 2000MY Focus vehicles which specify Super DOT 4 brake fluid. Should not be used to service vehicles specifying DOT 3 brake fluid. Meets Super DOT 4 minimum wet boiling point of 356F (180C). Conforms to federal motor vehicle safety standard no 116. Meets Ford specification ESD-M6C57-A."

Sounds like they had a problem with the Focus.....

 

[Joel]

Thanks Don
Those sites are really useful and 5.1 seems to come out well. Since its on my shelf and performs well I'll probably use it.
Nadine
For most cars I use a gunsons eezibleed. It uses a tyre to pressuise the system but you need to use a low pressure. Hi-pressure can make the reservoir expand alarmingly.Less than 10psi is ok. Also it doesn't come with caps to fit everything.
Jon
I won't use silicone, I've heard so many of the classic car boys complaining about spongy pedals, and one of those sites mentions abs valve aeration! yeugh

 

[Daffy]

OK, I've got to ask the dumb question of the day, I've heard it many times & never asked why, so here it goes: why shouldn't you use silicone (DOT5) brake fluid? I'm just curious - and too bright about brake fluid.

Dave.

 

[Nadine UK GTS]

Daffy, it does not mix with any other brake fluid, so you have to well and truly rid your pipes of all old fluid (I think it reacts and goes gunky). It does not absorb any moisture either at all, as heat builds up, any tiniest bit of moisture behind the piston boils...and spongy pedal, scary and horrid when you go for a late brake!

Joel, thanks for the bleeding tool info. I had thought about using that, but didn't know if it would be enough pressure. As always, I went OTT and probably gave it too much!

 

[Jay Lopez]

For those looking for a brake bleeder, check out Griot's Garage at http://www.griotsgarage.com/search.jsp?searchtext=bleeder .

 

[slaughterj]

I got a response from Skip Thomas of ViperDays, who said it was Ford truck heavy duty brake fluid DOT 5 he was referring to...I haven't heard that mentioned here though...

 

[Tom Shapiro]

Here's another option. Check out this site. Good info and very reasonably priced. www.speedbleeder.com