Non-synthetic DOT-5 Brake Fluid - PeachParts Mercedes-Benz Forum

Mike Murrell · #1 08-21-2002, 10:59 PM

Does anyone know of a company that makes such a product? Thanks.

Kestas · #2 08-22-2002, 09:24 AM

First, why are you considering DOT 5 brake fluid? This brake fluid is formulated with silicone and is not recommended for use with ABS systems. Also, silicone-based fluids should be mixed with glycol-based fluids....they will coagulate.

I'm not sure what is recommended in the owners manual for your 1991 model, but you may be thinking of DOT 5.1, which is a glycol-based brake fluid (DOT 3 & 4 are also glycol-based), and has superior dry and wet boiling points.

Mike Murrell · #3 08-22-2002, 01:04 PM

It's my understanding the DOT-5 synthetic contains silicone; the non-synthetic version does not and is therefore acceptable in ABS systems such as mine.

Kestas · #4 08-22-2002, 01:52 PM

I agree. I don't see any reason why you can't use the DOT 5.1 fluid in your brake system.

Not to mince words, but I believe both DOT 5 (silicone) and DOT 5.1 (glycol) could be called synthetic. So be careful when ordering, to refer to the DOT number and not refer to it as synthetic or non-synthetic.

Mike Murrell · #5 08-22-2002, 02:57 PM

Searching the WEB, I found 2 companies thus far who make a 5.1.

Motul and Wagner. The term "severe service" appears on the Wagner product, but neither indicates a silicone base.

J.HIDALGO · #6 08-22-2002, 03:32 PM

It advertises " Maximizes ABS performance, Exceeds DOT 3 & DOT 4", "Mixes with conventional brake fluids".

It contains "a complex mixtures of glycol ethers, polyglycols and inhibitors"

Kestas · #7 08-22-2002, 03:53 PM

Here's a link to a respected automotive website with an article on brake fluid. It may clear up some confusion.

Brake Fluid