Thread: Son used DOT 5....what a mess!!!!

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My son and I messed up. We grabbed my DOT 5 for my race bikes without a thought in the world and filled the master cyclinder while bleeding brakes on my sons 65 El Camino. I only got the DOT 5 in the rear lines.I hadnt bled the fronts yet. Went to local parts store and bought a gallon of DOT 3, just figured on vacuum bleeding whole thing.

Pulled the master cyclinder, drained it, put in fresh DOT 3 and bench bled it. Odd thing I noticed while bench bleeding (this is a power dual master off like a late 70's or early 80's Vette, 4 port only using 2 ports), the most I could push in the valve was 1/8" with it in the vise. It just wouldnt go any further period! I remounted and set up with the vacuum bleeder and focused on the rear. I cant tell you I've ever seen anything quite like it. Looks like foam. Now I know DOT 5 & 3 will not intermix, but I sure thought after a gallon of fluid, I'd have most of it out of there. Question is, what now? Am I going to have to change everything out or is there a trick I can use (like a grease remover DX330 or mineral spirit to purge the 5 out?)? Should I just drain the DOT 3 out and go with the DOT 5.

I was able to bleed the fronts without any trouble. The pedal does go to the floor but I'm fairly certain thats because of the air in the rear line. When we use the 2 man method with Dustin on the brake pedal and me craking the bleeders.....the fronts move a lot of fluid as I'd expect. But the rears move no fluid. With the vacuum set up on the rear I can move quite a bit of fluid (have to keep an eye on filling the resevoir). Something else I noticed. When son depresses pedal I can see the front resevoir trying to spit fluid out like normal. But the rear there is no activity. In fact the fluid is murky in the rear resevoir even though I cleaned it good before the bench bleed.

Bless my feeble mind please. LOL's.

David

From what I read on some of the bike sites if you introduce DOT5 it attracts all of the contaminants in the system and plugs things up. One Brit site says that it is impossible to go back to a non-silicone fluid, as you cannot get all of the silicone out. I don't know that to be true, but it looks like you've got a mess on your hands. I see the possibility of a new master cylinder and rear wheel cylinders/calipers, and a good flush of the brake lines, maybe after blowing them out with high pressure air? Just guessing here - also saw warnings against mineral spirits or alchohol for flushing - here:DOT 5 silicone brake fluid warning

Thats what I was affraid of Roger. I found serveral links suggesting flushing with denatured alcohol but I would most likely still have to change the calipers front and rear as well as the combi valve because they would be soo hard to get all of the DOT 5 and or the alcohol out. Fiddle sticks! I can tell you how aggrevated I am with myself right now. I knew better!.

Thanks,
David

Yeah, I read this on a brake forum:
Disconnect all the lines and flush with denatured alchohol useing a rubber tipped syringe. If you rebuild, rather than replace components, also clean them with alchohol. Once the lines are disconnected at both ends, the alchohol should flow freely. If there is an obstruction, use compressed air. Do not use compressed air with components still attached. Sometimes rubber parts can seem to survive something like this, only to go bad later, including the flex lines, if they have been infected. I have gone the cheap/easy way before, if i believed the contamination was isolated to the master, and just replaced a contaminated master cyl, then back flushed the lines with new fluid via a syringe thru the caliper bleeders with the master removed, and not had a problem. but if you believe the contamination has made it's way to the calipers, or have any doubts, all rubber must be replaced, all metal must be flushed with alchohol. On a personal note: I was not aware that a dot 5 and 3 (or 4) mix would swell seals. I knew they were not to be used together, but assumed they just did not intermingle. it is good to know.

Sounds like anything rubber has to be rebuilt/replaced, including flex lines. Bummer!

Thanks Roger!

Yikes! I'm running dot 5 in the hotrod, but it has all new lines, master, and wheel cylinders. I hope my wife never grabs the 5 for the daily drivers!

The "pleasures" of silicone/DOT5 fluid. I had a bright idea years ago with my T-bucket that I should use that stuff as it is not hygroscopic and that I would NEVER have a problem. Spongy pedal and poor braking. Expensive mistake. New wheel cylinders - yeah, probably could have rebuilt them but new were only a few bucks more then a kit. new MC (same as the wheel cyl's, but...) new front braided lines. The Wilwood front single piston calipers were rebuilt, but they are not cheap kits. Then a bunch of alcohol to wash the lines, etc, etc, etc along with many hours.

Lotsa luck on your brake system cleaning

Originally Posted by stovens

Yikes! I'm running dot 5 in the hotrod, but it has all new lines, master, and wheel cylinders. I hope my wife never grabs the 5 for the daily drivers!

Steve, is it DOT 5 or DOT 5.1? To make things confusing DOT 5.1 is compatible with DOT 3 & 4, but DOT 5 was a military development and is non-hygroscopic, as I understand, to eliminate the need for occasional flushing.

Pretty Sure it's DOT 5, silicone. Bought it for the anti rusting features.

silicone is for breast implants, not ever to come around paint jobs or brake systems----

I had an issue with Dot 5 (militaryspec?)) when I was in Army--was pretty severe and lots of brass telling me I ws wrong--had pretty major issues going from me and the Commanders Jeep all the way thru 3rd Army to Pentagon---
It was developed so that it could be used in vehicles that were stored on that island resupply base located in Indian Ocean---they thought that a fluid that wouldn't MIX with water was better than ome that absorbed water----were they ever wrong--

You'll need to replace every piece of anything rubber type material

X 2, Jerry is dead right, terrible stuff

I've read that Harley Davidson uses it because it does not harm paint, but it seems that it's not considered a good "performance" fluid - DOT3, 4 and 5.1 are all much better high temp fluids. Sounds like nasty stuff!

This is the 'stuff' I'm using in my '31. Not cheap @~$15-16.00 a litre can, but doesn't absorb much water, is high temp and DOT4. When you do a change out, they have an amber color also so you know it's been flushed completely.

" Blue tint of fluid makes bleeding brakes easier
Ideal for race use, excellent choice for street driven vehicles, too
Boiling point minimum: 536 degrees F
Wet boiling point minimum: 388 degrees F
Viscosity at -104 degrees F: max 1,400 mm 2/5
Designed to last up to 3 years under normal highway driving conditions"


ATE Blue Brake Fluid.JPG

ATE Super Blue Racing Brake Fluid

Originally Posted by rspears

I've read that Harley Davidson uses it because it does not harm paint, but it seems that it's not considered a good "performance" fluid - DOT3, 4 and 5.1 are all much better high temp fluids. Sounds like nasty stuff!

Roger, I work at a H-D dealer and I've seen the effects of mixed brake fluids, it isn't pretty. Harley used DOT 5 for many, many years but changed to DOT 4 on their 2005 models. The change to DOT 4 was due to ABS being used on 2005 police bikes (though ABS wasn't available on civilian bikes yet). Harley slowly integrated ABS on its civilian bikes beginning with some of the 2008 models. With the release of the new 2012 models only a few days ago, all H-D models except the Sportsters are now available with ABS.

David, unfortunately, as Jerry and Steve said, replace everything in the system that's made of rubber.

Mike

Prior to my purchasing my 34 Ford Street rod, someone had mixed DOT 3 and DOT 5 together but I didn't know it. The brakes were like pushing boulders around with your feet. Trying to diagnose the problem, I went to bleed the brakes. The stuff came out looking like bananna pudding. It was like yellow glue. I took around a gallon of DOT 3 brake fluid and with someone in the car pushing on the brakes, we got everything out... but it did take a gallon of it. That was in 2005 and have not had a brake issue since. It was a long day of laying under the car with my daughter reading a book and pushing the brake pedal when I asked her. She got the best leg workout that day!!!