DOT4 Brake Fluid Chemisty...

90210brandon

Be a Zero
Joined
Oct 3, 2013
Messages
101
Location
Vancouver
Bike
07 Silver ST13
STOC #
8998
Why is the above-mentioned ok to clean the brakes?

Maybe this is a silly question, but why is DOT4 ok to clean the brake pad callipers? Why is it ok to clean the outside of the callipers? What if the DOT4 fluid is used to clean the rims of the ST1300? I am trying to figure out the chemistry of this stuff.

If you can use it to clean the pistons in the calliper, what if it gets on anything else, like dripping onto the rims...just curious.
 
Joined
Jun 3, 2006
Messages
3,514
Location
British Columbia
Bike
2021 RE Meteor 350
Brake fluid will strip paint, so don't put it on the rims. Use brake CLEANER to clean brake parts, but use brake FLUID to re-assemble the pistons and seals.
 
Joined
Sep 4, 2013
Messages
8,115
Location
Cleveland
Bike
2010 ST1300
Brake cleaner should not be used on any rubber parts (seals, boots, etc.) on the brakes.
 
Joined
Jun 3, 2006
Messages
3,514
Location
British Columbia
Bike
2021 RE Meteor 350
Brake cleaner should not be used on any rubber parts (seals, boots, etc.) on the brakes.
Let's clarify this further. You can use brake cleaner to clean all the metal parts WHEN the caliper is disassembled, but on re-assembly, use brake fluid to lube the new rubber parts and pistons.
 

wjbertrand

Ventura Highway
Joined
Feb 8, 2005
Messages
4,407
Location
Ventura, CA
Where did you hear that you could clean parts with brake fluid?


Sent from my iPhone using Tapatalk Pro
 
Joined
Oct 6, 2007
Messages
523
Location
Kenly NC
Bike
07 ST1300A(P)
STOC #
7649
I will toss this in here, although, if the OP can't get DOT4 it's unlikely he can get this: DOT5.1. Not to be mistaken with DOT5, which is silicone based fluid, and useless in an ABS system due to it's foaming characteristics. DOT 5.1 is polyglycol based and has a higher heat rating than 4. It's also pretty expensive compared to DOT4. I've used it in high performance applications where extreme heat is an issue. That being said, I've also used DOT5 in applications also, but this was on fresh systems, with *all* new parts, and no ABS to contend with. DOT5 does not mix with DOT3, DOT4 or DOT5.1. DOT5 tends to foam when subjected to an ABS pump, resulting in loss of braking.
I have, in an emergency, replaced DOT4 with DOT3 with no issues, but have replaced it when I had access to DOT4.
Which reminds me, I need to look at my front brakes, noticed the fluid seemed low today.

*realized I responded to the wrong post, but will leave it here due to somewhat relevant info
 
Last edited:
OP
OP
90210brandon

90210brandon

Be a Zero
Joined
Oct 3, 2013
Messages
101
Location
Vancouver
Bike
07 Silver ST13
STOC #
8998
I have read several people use DOT4 brake fluid to clean the calliper pistons.

I have seen a video on RevZilla where the mechanic uses aerosol brake cleaner on the pistons.

So is it just your opinion or is there validity to it?

Next question, what happens if you get some brake fluid or cleaner on the brake pads or the brake rotors? Aerosol is hard to control (spray/mist/cloud can go anywhere) and yet, people use it.
 
Joined
Sep 4, 2013
Messages
8,115
Location
Cleveland
Bike
2010 ST1300
I have read several people use DOT4 brake fluid to clean the calliper pistons.

I have seen a video on RevZilla where the mechanic uses aerosol brake cleaner on the pistons.

So is it just your opinion or is there validity to it?

Next question, what happens if you get some brake fluid or cleaner on the brake pads or the brake rotors? Aerosol is hard to control (spray/mist/cloud can go anywhere) and yet, people use it.
You can use just about anything to clean the pistons as long as what you are using does not attack the rubber seals, rings, boots. Brake fluid will obviously not be harmful, but brake cleaner does damage the rubber parts. I've read that alcohol is good to use as well. But, I would not use anything more than brake fluid on an assembled caliper.

My auto mechanic cleans a little brake fluid off pads with a lot of wear left in them with brake cleaner - several times. He has told me its a judgement call. If a leaking slave cylinder soaks the pads, he throws them away and replaces them. I would assume the same goes for your bike's pads. But, spraying brake cleaner on the pads when they are on the bike is going to result in spraying the rubber parts. Will this little bit damage those parts? Depends on the exposure.

Bush has it right, above.

Brake fluid on the rotors will lubricate them - not a good idea for brakes. Brake cleaner will clean them of any oil film and evaporate.
 
OP
OP
90210brandon

90210brandon

Be a Zero
Joined
Oct 3, 2013
Messages
101
Location
Vancouver
Bike
07 Silver ST13
STOC #
8998
Thanks SMSW.

Since I just changed the brake pads and cleaned the pistons with DOT4 fluid, I think I'll spray the rotors with Brake cleaner just to be sure they are clean of any DOT4.

It would be terrible to have gotten some DOT4 on the rotors and then apply the brakes only to contaminate the pads, after they had been installed, assuming they stop me first, haha!
 
Joined
Jun 3, 2006
Messages
3,514
Location
British Columbia
Bike
2021 RE Meteor 350
Thanks SMSW.

Since I just changed the brake pads and cleaned the pistons with DOT4 fluid, I think I'll spray the rotors with Brake cleaner just to be sure they are clean of any DOT4.

It would be terrible to have gotten some DOT4 on the rotors and then apply the brakes only to contaminate the pads, after they had been installed, assuming they stop me first, haha!
Avoid the overspray possibility by spraying the cleaner onto a clean rag and then thoroughly wipe both sides of the rotor(s).
 
Joined
Oct 6, 2007
Messages
523
Location
Kenly NC
Bike
07 ST1300A(P)
STOC #
7649
Years ago, we used to use brake rotor shavings to clean the pistons, drop the pistons in a bucket with the shavings, then grab them and a handful of shavings, start rubbing. Worked great.
 
OP
OP
90210brandon

90210brandon

Be a Zero
Joined
Oct 3, 2013
Messages
101
Location
Vancouver
Bike
07 Silver ST13
STOC #
8998
Thanks everybody. Suffice to say, I finally took the maiden voyage after I replaced the brake pads for the firST time on the bike and they work flawlessly. Man, I love this bike. It was so easy to change the front brake pads.

Now when the STealership has the rear pads in (back ordered, weird eh?) stock, I'll replace the rears.

Any advice on doing the rears? Move the exhaust out of the way, maybe?
 
Top Bottom