Any horror stories involving synthetic brake fluid?

[michaeld]

Hi,
I'm replacing my master cylinder this weekend, and will be replacing brake fluid. I did my shopping at Autozone, and all their brake fluid was cheap #$%* except for DOT 4 Valvoline SynPower Synthetic. It meets or exceeds SAE 1703B and FMVSS #116 just as the MBz Technical Manual recommends.

However, since I have an older car (77 450SEL) I am always cautious when using synthetic products. Has anyone with an older car had this stuff causing or creating leaks or anything? I'd really like to know before I pour it in.

Also, I'm a little baffled on "synthetic" brake fluid: isn't brake fluid specifically NON-petroleum? Isn't regular brake fluid a synthetic to begin with? What are the advantages of this product for future knowledge?

[Ara T.]

Its kinduva marketing gimmick, just regular ole brake fluid. I've been using it since I've had my 300D. No leaks or anything.. good stuff. Speedbleeders are nice to have too!

[t walgamuth]

speedbleeder, what is that? (seriously)

sounds like a politician. (joke)

one thing i do recommend against (seriuosly) is silicone brake fluid in a benz. the ones with disc brakes. older duim brake cars it would be fine i think.

tom w

[Benzcrusher]

I bought the Motive Products power bleeder 2 years ago and love it. One man operation and a real time saver.

[rg2098]

Speed bleeders basically replace the bleed nipples on the calipers with 1 way valves. You attach a bag to the end, loosen the bleeder and pump the brakes. The valve inside the new bleeder doesn't allow air back into the system. I replaced them on a 300SL Gullwing that I bleed brakes on ever month or 2. It makes the job about 3 times quicker.

speed bleeder

[Matt L]

The trouble with a valve in the bleeder is that the threads can still leak air into the slave cylinder when you release the pedal.

A better and much faster solution is a power bleeder. They're not extremely expensive. Get one with a reservior to make the job even easier.

[t walgamuth]

i have never had much luck with power bleeders. for me they were always too much trouble to offset the disadvantage of getting my wife to push on the pedal.

tom w

[michaeld]

Okay, I get it - you guys want to talk about power bleeders!

Is there anyone out there who would like to talk about their experiences with synthetic brake fluid?

And while I'm at it, does anyone know if the standard method of bench bleeding master cylinders (manually "plunging" the cylinder) works with the MBz dual system? I'd hate to find out I'd only bled half the cylinder.

[t walgamuth]

sorry, i havent heard any negatives about the synthetic brake fluids.

and bench bleeding will work with the dual mc, but personally i havent found it to be all that helpful and can make a mess.

tom w

[michaeld]

t walgamuth,
Thanks for getting back to me. I'm hearing some bad stories about "synthetic" brake fluid, but it sounds like some people are confusing "synthetic" and "silicone." Silicone is a definite no no for our application. At this point, I'm planning to go ahead and use the synthetic. I'll update this thread to post my "results" after I do the job.

BTW, as I understand it, bench bleeding the master cylinder is necessary when you are replacing the M.C. Many times someone might bypass this step and have no problems; but plenty of times air that is trapped in the M.C. is virtually impossible to remove - at least w/o the pressure bleeders some of you guys were fixating over above!

Thanks for the info on "manual bleeding" being okay in dual cylinders. I'll probably try my Mityvac first and see how that goes. If I have problems, I'll resort to the tried and true.

[Tomguy]

The mityvac makes brake bleeding a snap. I know, I've done it. I didn't let my lines run dry - I opened the valve, kept the resevoir full, and sucked until the fluid was clear from each caliper.

I dont think there'd be any problems from synthetic brake fluid - brake fluid is brake fluid. I usually use Dot 4 from Wal*Mart, I think it's prestone.