Brake Fluid Recommendations?

[PlayingWithTBI]

Yeah, once you open a jug of brake fluid, it doesn't take long before it's contaminated with moisture, especially in the rust belt. I inherited a 1 gallon can of DOT 3 when we bought this house.
I'll never use that much before it goes bad

 

[OutlawDrifter]

I'm sure you're probably right, but I'm also the type of guy who 4L80E swaps a V6 half ton because he's sick of killing 4L60Es.

I'm a "spirited driver" on occasion and I like overkill when it comes to reliability. The rest of my brake setup that's going on this truck is fairly performance oriented and I wouldn't mind having a nice fluid to go along with it. This truck is eventually getting a cammed LQ4 so going fast isn't out of the realm of possibility, I hope anyway.

I get it. If you're that serious about brake performance, just swap to hydroboost and get it over with! My point is, brake fluid, like coolant and differential goo, is probably one of the most over looked fluids in a vehicle. Yet vehicles still stop at 20yrs and 250k miles. I also understand the overkill, but I don't think stepping up to DOT 4 or 5.1 is going to gain you overkill. All personal experience and opinion...so you get what you paid for here, haha.

Owning two 6.0L swapped vehicles, brakes are a good thing. My '49 GMC is on stock 4 corner S10 disc brakes with Powerstop rotors/Z16 pads, it stops plenty good.

My Z28 is due for a brake upgrade, however, but it also has more than twice the HP it had stock.

 

[df2x4]

I also understand the overkill, but I don't think stepping up to DOT 4 or 5.1 is going to gain you overkill.

Luckily if I go with that Wilwood 570 I won't have to, as it's a DOT 3 fluid with higher boiling points than many DOT 4s. I get where you're coming from though. Sometimes I just like to spoil the trucks a little.

My '49 GMC

Well that's awesome... Do you have any pics or a build thread on that one?

 

[Supercharged111]

I used to be better about my annual brake flushes. I just use off the shelf DOT4 for the higher boiling point. Is it necessary? Not really. The only car I've ever boiled the fluid in is my Z06 on the track, and that wasn't entirely the fluid's fault. Don't overthink it, new fluid is better than old. If you want to blow your load on fluid, you can get what I run in the Camaro.

https://www.amazon.com/Castrol-SRF-...=1&keywords=castrol+srf&qid=1621956050&sr=8-3

 

[Pinger]

FYSA, the "dry" boiling point is fresh fluid. The"wet" boiling point is what you can expect if you let the brake fluid get old. Brake fluid is hydroscopic, meaning that it soaks up moisture. The wet boiling point is the boiling point when the fluid is saturated. Typically, racing fluids go bad faster but have a higher wet boiling points. Street fluids take longer to soak up the moisture, but it can bring them down to a dangerously low boiling point - which causes brake fade.

If we have any brake engineers on here, feel free to set me straight, but this was the info I picked up when researching brake fluids for my car.

Technically, 'brake fade' occurs with overheating of the friction material. IIRC, the bonding adhesives start to melt into liquid and create a lubricating layer. With fade the pedal is still rock solid and requires monumental effort to stop - accompanied by a bad smell (from outside the cabin but not exclusively).

What you are referring to when the fluid boils leads to a sudden collapse of the pedal when the fluid boils to vapour and behaves as air in the system - nasty!

 

[Pinger]

Here's the bottle I cracked open today. Found the last (empty) bottle and it was DOT4 and 'synthetic formulation' also.
In my driving life I've never worried too much about fluid. Fade (see above post) has always got me first.

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[df2x4]

I used to be better about my annual brake flushes. I just use off the shelf DOT4 for the higher boiling point. Is it necessary? Not really. The only car I've ever boiled the fluid in is my Z06 on the track, and that wasn't entirely the fluid's fault. Don't overthink it, new fluid is better than old. If you want to blow your load on fluid, you can get what I run in the Camaro.

https://www.amazon.com/Castrol-SRF-...=1&keywords=castrol+srf&qid=1621956050&sr=8-3

Those are some impressive boiling points but good lord that's expensive stuff! Almost twice as much as that Wilwood 570 I linked earlier. I'm assuming this is DOT 4 or 5.1? It says "exceeds DOT 3 and DOT 4 specifications" but I'm not seeing an actual DOT rating.

 

[0xDEADBEEF]

Unless you are tracking it or towing something heavy without trailer brakes, it doesn't really matter. I run the cheapest DOT 4 on my street vehicles and never had a fluid related problem.

Motul 5.1 has worked well for me in my old track car, but I did a full flush before every track weekend so I never saw issues with old fluid. I have only ever had brake fade at one track, Circuit of the Americas braking from 145 to ~45 MPH and that was on the stock pads after 6 laps. (Ruined a bunch of rotors though.)

Picked up some Wilwood EXP DOT 4 for the new one since it still has a warranty and wanted to use what GM recommended, which is DOT 4.

 

[Supercharged111]

Those are some impressive boiling points but good lord that's expensive stuff! Almost twice as much as that Wilwood 570 I linked earlier. I'm assuming this is DOT 4 or 5.1? It says "exceeds DOT 3 and DOT 4 specifications" but I'm not seeing an actual DOT rating.

It's not quite as stiff of a pedal. I think it claims to be DOT4 but also has some silicone in it like DOT5? I purged from that to Motul 600 and back to SRF with no strange side effects, I used about 750ml both times.

 

[Supercharged111]

Those are some impressive boiling points but good lord that's expensive stuff! Almost twice as much as that Wilwood 570 I linked earlier. I'm assuming this is DOT 4 or 5.1? It says "exceeds DOT 3 and DOT 4 specifications" but I'm not seeing an actual DOT rating.

I used the 570 before and this stuff blows it out of the water. Here's the bottle.

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