• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Re-doing my drum brake system. What is the best choice for brake fluid nowadays?

So basically no interaction with dot 3 and silicone? I ask because I just rebuild my bendix calipers and used a silicone basesd. lubricant for assembly as per the instruction in the FSM. I was running dot 3 before and wondering if this going to be a problem now ?
 
If you're worried about moisture getting in your brake system because you don't use the car much, I'd go with DOT 5 silicon based fluid. I've used it on my Army Dodge W200 power wagon for years with no issues. You would have to flush the lines and replace all of your rubber components (flex hoses, master cylinder rubbers, wheel cylinders, etc.) first before you put in the DOT 5 because it doesn't mix with the DOT 3 or 4. If the thought of replacing all of your rubber parts seems too spendy to go with DOT 5, then use DOT 3 or 4; those fluids are perfectly adequate for use in brake systems.
 
I previously said, DO NOT mix DOT 3 or 4 with Silicone brake fluid! Not compatible!
 
I previously said, DO NOT mix DOT 3 or 4 with Silicone brake fluid! Not compatible!
Right. I'm not trying to switch fluids but I did use grease to slide the seals over the pistons and to help them slide into the bore. From my understanding that was a no -no ?

I forget exactly what they called it n the FSM but when i looked it up, equivalent was a synthetic or silicone lube.
 
I would just use DOT 5 fluid to lube the parts. Grease is something other than the fluid and I
have no idea if there will be a problem or not. If it's synthetic or silicone lube, you should be
fine. It's scary what old brake fluid turns into after ten or twenty years! I put new wheel cyl-
inders in my car and lubed them with DOT 3 brake fluid and came back twenty years later.
Had to throw them away an buy new. They were welded together! Dot 3 and moisture.
 
My Harley called for dot 5. I accidently topped it off with dot 3. Master and caliper seals became trash and required rebuild and flushing of the lines. I learned a valueable but expensive lesson.
I used dot 3 in my '63 B body without any issues.
 
Yes, I did a search, but most of the brake fluid threads are old. I'm going thru the brakes on my 67 R/T. I just took everything apart, and while there is less than 10K miles on it since I did the brakes before, it has also been over 25 years. There has been some condensation in wheel cylinders. I plan to replace all wheel cylinders and rubber hoses. The master cylinder was replaced about 12 years ago, so I have not decided on it yet. May pull it apart and take a look. Anyway, what do you guys think is the best brake fluid to use now? My cars mostly sit a lot, but I am hoping to drive them more now that I am retired and have time.
I have always used DOT 3, but wonder if one of the newer fluids would work better for me as far as not having moisture problems.
Thanks
edit: This is the original 11" manual drum brakes.
use what the owners manual calls for (dot3 i think walmart should have it of yyur local parts store)
 
The secret to using DOT 3 or 4 is flush and change it every couple of years, but it will
still swell and collapse the inside of the hoses!
 
brake-fluid-compatibility-chart.png
In addition, Brake fluid is not compatible with any - ANY petroleum products. That includes solvents for petroleum products.
 
Last edited:
Auto Transport Service
Back
Top