Let's talk brake fluid
#1
Let's talk brake fluid
Got my new chrome front end stuff in. One of those items is the chrome brake reservoir. So I need to replace my brake system.
In '05, the MoCo went back to DOT 4 brake fluid. A few of the previous years were DOT 5.
My understanding is that DOT 5 has a higher heat tolerance than DOT 4, and DOT 4 higher than DOT 3.
Well, the new reservoir, and the stock reservoir both state, "DOT 4 only".
I head down to the Auto Parts store, and the closest thing they have is Valvoline synthetic, which states, "Exceeds Dot 3 and Dot 4". I asked the guy if they had any DOT 4, he pointed me to the Valvoline.
What difference does it make? I bought the Valvoline stuff, I'm headed to the garage to start this job, I'll check back. Should I head down to the HD shop and get their over-priced crap?
Mac
In '05, the MoCo went back to DOT 4 brake fluid. A few of the previous years were DOT 5.
My understanding is that DOT 5 has a higher heat tolerance than DOT 4, and DOT 4 higher than DOT 3.
Well, the new reservoir, and the stock reservoir both state, "DOT 4 only".
I head down to the Auto Parts store, and the closest thing they have is Valvoline synthetic, which states, "Exceeds Dot 3 and Dot 4". I asked the guy if they had any DOT 4, he pointed me to the Valvoline.
What difference does it make? I bought the Valvoline stuff, I'm headed to the garage to start this job, I'll check back. Should I head down to the HD shop and get their over-priced crap?
Mac
#2
RE: Let's talk brake fluid
Mac
I would STRONGLY suggest a ride to the dealer for the proper fluid, check to see if the dot 4 is ALL 05 bikes or JUST the cop bikes, not sure here! Dot 5 is silicone, the others are not. The abs on cop bikes is why they went back to dot 4
There is a big problem with mixing fluids. Usually if this happens, even in small amounts, a complete disassemble , cleaning and replacement of the seals is in order. Don't go by the auto store guys on this one.The silicone and others DO NOT MIX without problems. A few $$ spent now will save you a world of grief later. JMHO
I would STRONGLY suggest a ride to the dealer for the proper fluid, check to see if the dot 4 is ALL 05 bikes or JUST the cop bikes, not sure here! Dot 5 is silicone, the others are not. The abs on cop bikes is why they went back to dot 4
There is a big problem with mixing fluids. Usually if this happens, even in small amounts, a complete disassemble , cleaning and replacement of the seals is in order. Don't go by the auto store guys on this one.The silicone and others DO NOT MIX without problems. A few $$ spent now will save you a world of grief later. JMHO
#3
Join Date: Dec 2004
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RE: Let's talk brake fluid
The world is leaving DOT 3 & 5 and going to the DOT 4. DOT 5 is silicone based and used to be touted for not being hygroscopic, or water absorbing. It had a high boiling point and that made it good. But it is incompatible with ABS components. DOT 3, the old standard, had a lower boiling point, and it was hygroscopic, which lowered the boiling point ever more as more water was absorbed into it over time. DOT 3 eats paint, while DOT 5 won't hurt paint. Don't know about DOT 4, though I suspect it'll be mean to paint.
The new DOT 4 has nearly as high a boiling point as the DOT 5, isn't s'posed to be as hygroscopic as DOT 3, is compatible with ABS components, and gives a firmer pedal feel than DOT 5.
Wal Mart carries DOT 4, and it's much less expensive than the re-branded HD stuff.
As TCSTD sed, don't mix the stuff. If it doesn't eat your seals, it will start globbing up and really make a mess of the brake system. Of course, you won't find it out 'til Ida Mae Fiddle-Withers pulls out in front of you and there's an 18 wheeler in the lane next to you.
The new DOT 4 has nearly as high a boiling point as the DOT 5, isn't s'posed to be as hygroscopic as DOT 3, is compatible with ABS components, and gives a firmer pedal feel than DOT 5.
Wal Mart carries DOT 4, and it's much less expensive than the re-branded HD stuff.
As TCSTD sed, don't mix the stuff. If it doesn't eat your seals, it will start globbing up and really make a mess of the brake system. Of course, you won't find it out 'til Ida Mae Fiddle-Withers pulls out in front of you and there's an 18 wheeler in the lane next to you.
#4
RE: Let's talk brake fluid
They pretty well summed it up for you Pilot, follow their advice and you will be o-k. One other thing, if you ever use the dot 5 for anything, don't open it around any thing you are fixing to paint, the silicone will not let the paint stick properly.
John TN
John TN
#5
RE: Let's talk brake fluid
Thanks for the help. I guess I'll head back to the auto store for a refund, and head to Wally World.
FWIW, I had no intention of mixing, I'm completely replacing the brake system, reservoir, braided lines...all of it. I guess the caliper is not being replaced.
I'll get the DOT 4...
Thanks for the help,
Mac
FWIW, I had no intention of mixing, I'm completely replacing the brake system, reservoir, braided lines...all of it. I guess the caliper is not being replaced.
I'll get the DOT 4...
Thanks for the help,
Mac
#7
RE: Let's talk brake fluid
DOT 4 is a glycol-based fluid, while DOT 5 is silicone-based. They do not mix.
In '05, the MOCO started using DOT 4 in the FLHT family only.
The change to DOT 4 is reportedly due to requirements of the ABS, which may soon (?) be available on all FLHT's.
In '05, the MOCO started using DOT 4 in the FLHT family only.
The change to DOT 4 is reportedly due to requirements of the ABS, which may soon (?) be available on all FLHT's.
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#8
RE: Let's talk brake fluid
So technically, I could use the DOT 5...I don't have anti-lock brakes...I'll go with the DOT 4, but I just don't get it.
Mac
Mac
#9
RE: Let's talk brake fluid
ORIGINAL: pilot1996
So technically, I could use the DOT 5...I don't have anti-lock brakes...I'll go with the DOT 4, but I just don't get it.
Mac
So technically, I could use the DOT 5...I don't have anti-lock brakes...I'll go with the DOT 4, but I just don't get it.
Mac
John TN
#10
RE: Let's talk brake fluid
I guess I don't understand why they went backwards in technology...unless the DOT 5 doesn't work for anti lock brakes...TNW, I picked up the DOT 4 from Wally World today for $2.50.
Mac
Mac