macdarren

I am redoing my brakes along with most of the rest of the car.

I previously had DOT5 and it was not good. I have flushed or replaced everything so I can go back to DOT4 or DOT5.1 (I think that last is a non silicone fluid not sure) Anyway what non silicone fluid do people like....right now I am considering Wilwood's EXP600...sounds like it has the right charateristics....low water absortion, high wet point....and the one bad charateristic High Price tag....not that it matters that much, it does imply however it is for racing not hiway use...I don't know if that means I can't use it or if maybe it is a CYA move for something that is not actually DOT approved.

Mine is a manual disk brake car if that matters.
I would like to choose a fluid I can easily get so at flush time I can buy the same type. I do solo the car sometimes so is sees some serious braking thus a hi-temp fluid it best.

Thanks
Darren

SWCDuke

Any DOT 4 is fine for street and even "light" road racing, like track time events.

If you used DOT 5 you must thoroughly disassemble everthing, clean in denatured alcohol, to include new assembled hydraulic components since they are assembled with conventional fluid, and reassemble with silicone fluid.

You do not want even one molecule of conventional fluid in the system if you use DOT 5.

This is the mistake that guys make when converting to DOT 5. They try making the conversion by just flushing, which is a disaster, or they will take new hydraulic components that were assembled by the manufacturer/rebuilder with conventional fluid and install them without disassembling, cleaning, and reassembling with DOT 5.

Duke

Plasticman

Castrol LMA fluid. LMA stands for "Low Moisture Absorbtion", and I can attest that it works very well.

Saw the results of a direct comparison with cheap DOT 3 fluid turning rusty brown in a month, and the Castrol fluid still looks like new 10 months later (in humid/warm Florida). Both systems had been flushed/bled completely with a new master with the cheap fluid, and a rebuilt master in the other with the Castrol fluid. Have been using it for many years, and very pleased. Available at most auto parts stores.

Plasticman

kellsdad

I use standard DOT 4 in my Corvette and a higher performance brake fluid in the Cobra replica I run on road race tracks. In the Cobra I use ATE Super Blue and ATE Typ 200 Gold (dry boiling point of 536F and a wet boiling point of 396F) and I flush it before every track event. I like the convenience of changing brake fluid color with each flush. It makes it easy to tell when the old fluid has been replaced. ... I got my ATE fluid from an Internet source for about $9 per liter.

macdarren

I am actually changing from Dot5 back to 4. When I went to 5 I replaced all the lines and calipers and flushed the master cylinder, but you know I doubt I flushed the new rebuilt calipers...going back I am again doing rebuilt calipers fully disassembled and cleaned and I flushed the lines....didn't think about the alcohol for the lines I just blew them out with air then ran a bunch of cheap Dot3 through them, since I don't have anything assembled yet maybe I will go back and do the alcohol thing too then repeat the cheap fuild flush. Got a new master cylinder this time so I think I am good to go for the change back.

Thanks for the recommendation, keep them coming. The castrol and the synthetic valvoline are both pretty easy to get at the parts store maybe I will start with that, or the ATE stuff....

Darren

63 340HP

I ran the old F*rd heavy duty truck brake fluid for years (550dF dry boiling point). They recently changed the formulation and dropped the dry boiling point to 500dF. The performance is similar to Castrol LMA with similar availablilty (~$5 a bottle at any F dealer).

Something that also came up with the new F-spec fluid is the color choice option is no longer an option over the parts counter (or maybe the counter guy was too green to look).

Has anyone used a dye to successfully color clear brake fluid before a flush?

SWCDuke

You need to find a solvent that will dissolve DOT 5 silicone fluid, and use it to thoroughly flush the lines to remove any and all traces of the DOT 5. Otherwise you will end up with some DOT 5 residue, which may cause problems downstream.

As with converting from conventional to DOT 5, if you are converting from DOT 5 to conventional, you must remove every last molecule of DOT 5.

I don't know what solvent will dissolve DOT 5, so you're best bet may be to disassemble all the hydraulic components, thoroughly clean them with denatured alcohol, dry them and reassemble with DOT 5, the fill the system with DOT 5.

Most DOT 5 conversions fail because proper steps were not taken to remove any all all traces of conventional fluid. If this is done, the conversion will likey be successful. If not, the conversion will likey fail.

New brake hoses should also the thoroughly cleaned because they are often assembled using conventional fluid as an assembly lube.

Duke

ghostrider20

I run Dot 3, generic brand. It seams to turn color in a year or so. I bleed/change the brake fluid every other year.

Mark

macdarren

While we are at it, anyone know what the capacity of the manual disk brake system is? Seems the last time I did this it took about a quart+ to get it filled and bled. Once I fingure what to buy the next question is how much...Don't want to store it as I know it just gets wet sitting.

SWCDuke

Depending on year, somewhat less than a pint, so If you siphon all the old fluid out of the reservoir and start with fresh fluid, flushing a quart through should purge all the old fluid.

Brake fluid with the seal intact is good indefinitely. Once the seal is broken it aborbs moisture out of the air, but will stop doing so if the cap is installed tightly.

I use previously opened fluid, if I have any, for top offs, which are rare, and then use any remaining as the first amount to flush through on the next job. Since I have three cars in service and flush each every two years, it's used within a year, however, I usually always end up using a full quart - no more no less - for each job. Once I get down to the last few ounces of fresh fluid, I overfill the reservoir and then bleed it down the the correct full level.

Duke