[Starfire61]

I'm looking for some opinions-

I have a tired '61 Olds Ninety Eight convertible project. I'm in the midst of going through the entire brake system. It's almost totally shot, so every component will be either new or rebuilt.

Since I'll be starting with a new & empty system, I'm considering using DOT 5 fluid. I used it once before with excellent results, but I'd still like to hear some thoughts & experiences of others.

Thanks!

Chuck

[rocketraider]

Chuck, I've never used 5, so I can't offer an opinion. I had good luck with DOT 4 especially on the Toronado with its outrageous brake temperatures.

I'll sticky this for a while and see what we get.

[joe_padavano]

I've used DOT5 in several cars (including Oldsmobiles) with no problems at all. The beauty of DOT5 is that if you spill it on the paint, it makes a nice silicone "wax". [img]<>/grin.gif[/img]

[pfloro]

Hello Chuck:

Echoing Joe, DOT 5 has been in our '66 Mustang for 6 years. It's been completely trouble free. ALL the hydraulic brake components were new
before DOT 5 went in so there was no risk of contamination... The Mustang
was driven with DOT 5 in below freezing weather back east & now in 100+
temps in Arizona. I've never had to add a drop either.

I recommend it...

Paul

[joe_padavano]

I echo the replacement of rubber parts before converting to DOT5, but I will admit that in my young and stupid days, I simply drained the DOT3 out of a 71 Cutlass and filled it with DOT5. The brakes worked fine for about 10 years (though this was not a daily driver) and I never did need to add any fluid.

[Dave Wyatt]

I put DOT 5 in my 4-4-2, back in 1984, and the brakes are still working fine. I have added a little fluid over the years, but very little.

[rick60]

I've used DOT 5 for several years. The only problem was the failure of the brake light switch. I keep a few extra switches on hand. I've only replaced the switch in my Ford once in 10 years. I've never had to add fluid. No leaks have ever occurred.

[OldsmoREO]

The drawback is that at high altitudes, it gets mushy on you. I have noticed this effect when we go over 10-13K feet passes in Colorado. It isn't really bad, but it is noticeable when we drove our 1963 Cutlass Conv to the show in Denver.

As soon as we where down the hill you sould feel it get harder again....

[Hurst_Olds_1968]

Question,

If I wanted to convert to DOT 5 what would I have to do to purge the system of the old stuff? Will a denatured alcohol or some other chemical be needed to run through the lines first? I understand that if the 2 different types come in contact with each other it can turn to sludge???

Thanks

[rocketguy]

I have four wheel disc on my 442 and have used .5 for 12 years with no problems. It was basically a new system when I installed it though, and I would reccomend purging yours with something to rinse out the dot 3 if you do use dot 5. Dot 3 and .5 are not compatable liquids and will coagulate if put together.

The thing I 've read about .5 is that it does not absorb moisture. Therefore .5 will allow H2O to be a separate liquid in your brake system. If your brakes get REALLY hot, the H2O can then boil, introducing air into the system. This leads to a very undesireable situation. This is probably why OldsmoREO had the situation at high altitude. If you use .3, the H2O is absorbed into the fluid, therfore cannot boil under extreme heat.

Best of luck with your car!


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