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Will DOT 4 harm chrome?

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vrodent

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Discussion starter · #1 ·
Short story: Will DOT 4 brake fluid damage chrome?

Long story:
I just replaced the front brake and clutch master cylinders with chrome ones, and while I was very careful not to get any brake fluid on the paint, some fluid did get on the exterior chrome of the master cylinder. I washed the area with soapy water, and dried it with a towel. I live in an apartment and don't have access to a water hose, so I can't spray the area off.

Do I have anything to be worried about? Will the DOT 4 fluid harm the chrome? I have seen some Internet sites stating that DOT 4 will discolor chrome. The instructions from Harley only say that DOT 4 will harm paint and molded in color panels. No mention of chrome.

Thanks in advance.
 
#2 ·
vrodent said:
Short story: Will DOT 4 brake fluid damage chrome?

Long story:
I just replaced the front brake and clutch master cylinders with chrome ones, and while I was very careful not to get any brake fluid on the paint, some fluid did get on the exterior chrome of the master cylinder. I washed the area with soapy water, and dried it with a towel. I live in an apartment and don't have access to a water hose, so I can't spray the area off.

Do I have anything to be worried about? Will the DOT 4 fluid harm the chrome? I have seen some Internet sites stating that DOT 4 will discolor chrome. The instructions from Harley only say that DOT 4 will harm paint and molded in color panels. No mention of chrome.

Thanks in advance.
Click to expand...
It will discolor chrome if left on it for an extended period of time.
Eats paint much faster.You shoudn't have a problem.:D
 
#4 ·
You should have converted to DOT5 while you were at it :).
 
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#6 ·
RODent said:
You should have converted to DOT5 while you were at it :).
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I disagree. DOT 5 has far too many negatives to consider converting. It's ONLY benefit is that it doesn't harm paint.

DOT 3/4 (or DOT 5.1 which is really just enhanced DOT 4) is a far superior fluid for use in a braking system. It provides better braking feel, will last longer between brake flushes in vehicles used in less than daily operation and does not promote brake line corrosion like DOT 5 wen subjected to internal line condensation.

Stick with DOT 3/4, it's the best for performance and longevity.
 
#7 ·
mjw930 said:
I disagree. DOT 5 has far too many negatives to consider converting. It's ONLY benefit is that it doesn't harm paint.

DOT 3/4 (or DOT 5.1 which is really just enhanced DOT 4) is a far superior fluid for use in a braking system. It provides better braking feel, will last longer between brake flushes in vehicles used in less than daily operation and does not promote brake line corrosion like DOT 5 wen subjected to internal line condensation.

Stick with DOT 3/4, it's the best for performance and longevity.
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:them: I agree, my GF has a 2007 Street Glide which basically has the same brakes as my 2004 VRSCA except hers uses DOT 4 and mine is the DOT 5. The brake feel in the lever and pedal is night and day between the two with her Street Glide giving a firmer feel. Her Street Glide even has the basic black brake hoses and I have braided stainless hoses which is suppose to help the braking.
 
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#8 ·
Just wash it off with simple green and put some wax on it after your done. You also have to be careful with antifreeze on chrome cause it also corrodes it. I got some pitting on my CVO because of that.
 
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#9 ·
mjw930 said:
I disagree. DOT 5 has far too many negatives to consider converting. It's ONLY benefit is that it doesn't harm paint.

DOT 3/4 (or DOT 5.1 which is really just enhanced DOT 4) is a far superior fluid for use in a braking system. It provides better braking feel, will last longer between brake flushes in vehicles used in less than daily operation and does not promote brake line corrosion like DOT 5 wen subjected to internal line condensation.

Stick with DOT 3/4, it's the best for performance and longevity.
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Yeah - I should not have posted that without understanding his application. For anyone with a truely customized (not commuter VRod) - those with custom paint jobs and high end chrome - I would still suggest converting to DOT 5. DOT 5 does require more frequent maintenance and does have a different feel (not necessarily worse just softer - some of us like it that way). As for DOT3/4 being the best performance - depends on how you measure performance - looks like you measure it by brake feel and maintenance which to me is not a true perfromance indicator. With all that said I agree with your conclusion that the average joe should stick with DOT3/4. Oh, and you new ABS guys on the block - do not even think about using DOT5...
 
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#10 ·
RODent said:
Yeah - I should not have posted that without understanding his application. For anyone with a truely customized (not commuter VRod) - those with custom paint jobs and high end chrome - I would still suggest converting to DOT 5. DOT 5 does require more frequent maintenance and does have a different feel (not necessarily worse just softer - some of us like it that way). As for DOT3/4 being the best performance - depends on how you measure performance - looks like you measure it by brake feel and maintenance which to me is not a true perfromance indicator. With all that said I agree with your conclusion that the average joe should stick with DOT3/4. Oh, and you new ABS guys on the block - do not even think about using DOT5...
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Your point is well taken.

By performance I mean more than feel and maintenance. Modern DOT 3/4 and 5.1 ester based brake fluid provides a much higher boiling point even when diluted with up to 5% water (through absorption) than DOT 5. A higher boiling point means a better resistance to brake fade under heavy use.

The main difference between the two is how they react to moisture, DOT 5 will never absorb or bond with the water molecule. The moisture will remain suspended or separate and collect at the low points in your system. Under heavy and repeated braking the moisture will boil over at a temperature far below the boiling point of the DOT 5 fluid. This rapid expansion has the effect of vapor locking your brake system. DOT 3/4 (and 5.1) fluids absorb the moisture and prevent the free water from turning to steam. The net effect is a lower boiling point for saturated DOT 3/4 vs. virgin DOT 3/4 fluid but still at a MUCH higher boiling point than free water and with the best DOT 3/4 fliud, a higher boiling point than pure DOT 5.

The main reason DOT 5 feels "softer" is because of the trapped air introduced into the system during bleeding. DOT 3/4 will not trap as much air in this process so from the beginning it will have a better feel. DOT 5, properly installed and maintained is a perfectly good and safe system but from a performance perspective, by all objective measures, it's an inferior product IMHO.

Again, to your point, show bikes are never going to be ridden hard enough to expose the deficiencies of DOT 5 so for those it is probably the better choice.
 
#11 ·
ok, got a quick question. Had to replace the rear brake light pressure switch last night, picked one up from the dealer and they "sold" me the recommended DOT4 for my bike (03 VRSCA) - just bought the bike and didn't receive an owners manual so I asked what I needed.

Long story short, replaced the switch, bled the system, everything went smooth and easy. Was literally putting the top back on the rear resevoir and decided to read what it said (pretty low light in my garage or I would have noticed before I started) but it said "USE ONLY DOT 5"

So, the quick quesiton is... do I need to worry about anything? Are they compatable? Did I ruin anything? Should I do anything or just go ride? I did pump through about two completely full resevoirs full of fluid - so in a way i probably got most of the 5 out...

Suggestions please and thanks!

Tony
 
#12 ·
aneal000 said:
ok, got a quick question. Had to replace the rear brake light pressure switch last night, picked one up from the dealer and they "sold" me the recommended DOT4 for my bike (03 VRSCA) - just bought the bike and didn't receive an owners manual so I asked what I needed.

Long story short, replaced the switch, bled the system, everything went smooth and easy. Was literally putting the top back on the rear resevoir and decided to read what it said (pretty low light in my garage or I would have noticed before I started) but it said "USE ONLY DOT 5"

So, the quick quesiton is... do I need to worry about anything? Are they compatable? Did I ruin anything? Should I do anything or just go ride? I did pump through about two completely full resevoirs full of fluid - so in a way i probably got most of the 5 out...

Suggestions please and thanks! ...
Click to expand...
You'll probably hear as many different suggestions as you do responses (maybe more).

DOT 5 and DOT 4 are immiscible (do not mix) and the remaining DOT 5 will eventually form a emulsified goo that could cause problems.

You really should take everything apart and replace all the soft parts but I have heard others that did the exact same thing for the exact same reason with other DOT 5 equipped Harleys and they just left it alone except for increasing the fluid R&R period to once a year for at least three replacements.
 
#13 ·
aneal000 said:
ok, got a quick question. Had to replace the rear brake light pressure switch last night, picked one up from the dealer and they "sold" me the recommended DOT4 for my bike (03 VRSCA) - just bought the bike and didn't receive an owners manual so I asked what I needed.

Long story short, replaced the switch, bled the system, everything went smooth and easy. Was literally putting the top back on the rear resevoir and decided to read what it said (pretty low light in my garage or I would have noticed before I started) but it said "USE ONLY DOT 5"

So, the quick quesiton is... do I need to worry about anything? Are they compatable? Did I ruin anything? Should I do anything or just go ride? I did pump through about two completely full resevoirs full of fluid - so in a way i probably got most of the 5 out...

Suggestions please and thanks!

Tony
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Uhoh - that is not a good thing. Even though you ran a lot through the system you are still in trouble. Problem in the DOT 4 will destroy and seals and rubber o-rings over time as they are probably not DOT 4 compatible (I do not know for a fact on the 03 brakes) and you will have both fluids in the brake calipers causing a mess even though you flushed a lot through the system. You need to flush everything real good. If it were my bike I would take the calipers off the bike, split them, remove pistons, and completely clean. Use simple green and flush well. Also use an air gun if you have one to blow all the shiet out of everything (without getting the killer DOT 4 on your paint/plastic) - clean all rubber parts thoroughly - then reassemble and go back to DOT 5. THEN go to the frucking dealer if they indeed gave you DOT 4 for your 03 and lay it on the muther frucker - if you chose it yourself then kick your own ars.
 
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#14 ·
RODent said:
... DOT 4 will destroy and seals and rubber o-rings over time as they are probably not DOT 4 compatible (I do not know for a fact on the 03 brakes) and you will have both fluids in the brake calipers causing a mess even though you flushed a lot through the system. You need to flush everything real good. If it were my bike I would take the calipers off the bike, split them, remove pistons, and completely clean. Use simple green and flush well. Also use an air gun if you have one to blow all the shiet out of everything (without getting the killer DOT 4 on your paint/plastic) - clean all rubber parts thoroughly - then reassemble and go back to DOT 5. ...
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There's no difference in the seal materials used for DOT 4 and DOT 5 brakes on HD applications. I don't agree that the seals will suffer any damage from the DOT 4. The problem is the DOT 4/DOT 5 emulsion that should be cleaned off so I agree that he should completely disassemble the components and clean, but there is no need to switch back to DOT 5 (unless he wants to). Also, like I said, many other HD bikes have suffered this same problem and have worked fine by just flushing as he has done, but if it were my bike, I would do a through R&R using brake cleaner.

I haven't tried Simple Green on brake components, is this used because you can't use chlorinated HC brake cleaners in California? Have you tried d-limonene cleaners like Zep Big Orange or the "TriFree" from LPS? I can't argue that Simple Green doesn't work, but how do you rinse it off?
 
#15 ·
Yeah, the dealer sold me DOT 4 for my 03 V-Rod... he knew the exact bike I had, as he just had to look it up to sell me brake parts.

So it seems the ball is in my court... I can take the lazy way and hope, or spend a day with the bike in pieces.

How about this... I remove as much of the DOT4 as possible and then run DOT5 back through a few times to try and clear out as much of the 4 as possible. Then this winter when there is snow on the ground I'll take everything apart and clean. I'm sure I'll be dying to turn some wrenches by then anyways.

I guess my main concern was safety or instant incompatablitly that would cause immediate concern/issues. I'll take my chances for the next month or so and definatly let the dealer have an ear full next time I'm "in the area".
 
#16 ·
stever975 said:
There's no difference in the seal materials used for DOT 4 and DOT 5 brakes on HD applications. I don't agree that the seals will suffer any damage from the DOT 4.
Yeah - like I said I had no information of the older brakes. Where did you get the information about the seals being DOT 4 compatible - specifically inside the calipers? Only reason I ask is I talked to a Harley engineer a few months back and I recall him saying something different; but, I did not care since I have the Brembos (I talked with Brembo engineer too). I called them to verify some posts on this site were incorrect when peeps were saying Brembos are not DOT 5 compatible. Not that I don't believe you but a degraded seal could potentially put someones life at risk so I think source would be useful.
Click to expand...
Click to expand...
 
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#17 ·
aneal000 said:
Yeah, the dealer sold me DOT 4 for my 03 V-Rod... he knew the exact bike I had, as he just had to look it up to sell me brake parts.

So it seems the ball is in my court... I can take the lazy way and hope, or spend a day with the bike in pieces.

How about this... I remove as much of the DOT4 as possible and then run DOT5 back through a few times to try and clear out as much of the 4 as possible. Then this winter when there is snow on the ground I'll take everything apart and clean. I'm sure I'll be dying to turn some wrenches by then anyways.

I guess my main concern was safety or instant incompatablitly that would cause immediate concern/issues. I'll take my chances for the next month or so and definatly let the dealer have an ear full next time I'm "in the area".
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Don't do it Rambo. I just verified (if you believe HD engineers - I never know who to believe these days) that you can go DOT 5 on all HD brake systems but cannot go DOT 4 on older DOT 5 models as the seals are NOT compatible. You could potentially risk injury or death if your brakes leak - the most critical component on your bike. I also saw another thread this morning about some of the Brembo cylinders being incompatible with DOT 4 (again - not my post and I don't know the source of the information).

http://www.1130cc.com/forums/showthread.php?p=1076508#post1076508 item #12
 
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#18 ·
RODent said:
... Where did you get the information about the seals being DOT 4 compatible - specifically inside the calipers? Only reason I ask is I talked to a Harley engineer a few months back and I recall him saying something different; but, I did not care since I have the Brembos (I talked with Brembo engineer too). I called them to verify some posts on this site were incorrect when peeps were saying Brembos are not DOT 5 compatible. Not that I don't believe you but a degraded seal could potentially put someones life at risk so I think source would be useful.
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This is based on observations and experience:
Harley used the exact same part number components in 2005 for both DOT 4 and DOT 5 applications. E.g. the 2005 FL bikes (touring models) use the same front and rear calipers (and front master cylinder, except for color) that the 2005 VRSCA uses and in 2005 the FL bikes used DOT 4 but the VRSC bikes used DOT 5.

Also, it's just common sense. No brake manufacturer is going to make vehicle calipers or master cylinders that require one or the other fluid type. Since DOT 3/4 fluids are used by more than 99% of brake fluid users it would be quite expensive to make special seals just for DOT 5. Since DOT 5 is somewhat less damaging to soft parts, if a seal works with DOT 4, it'll work with DOT 5. I've read on some Brembo dealer sites that Brembos can't be used with DOT 5 saying that it will damage the seals, however, Brembo doesn't say this in their literature and I've used it in Brembos for years with no ill effects.

I do agree that this contamination should be followed with a through cleaning and perhaps seal replacments if the emulsion can't be cleaned. But the new seals that you would be using would work with either brake fluid type.
 
#19 ·
stever975 said:
This is based on observations and experience:
Harley used the exact same part number components in 2005 for both DOT 4 and DOT 5 applications. E.g. the 2005 FL bikes (touring models) use the same front and rear calipers (and front master cylinder, except for color) that the 2005 VRSCA uses and in 2005 the FL bikes used DOT 4 but the VRSC bikes used DOT 5.

Also, it's just common sense. No brake manufacturer is going to make vehicle calipers or master cylinders that require one or the other fluid type. Since DOT 3/4 fluids are used by more than 99% of brake fluid users it would be quite expensive to make special seals just for DOT 5. Since DOT 5 is somewhat less damaging to soft parts, if a seal works with DOT 4, it'll work with DOT 5. I've read on some Brembo dealer sites that Brembos can't be used with DOT 5 saying that it will damage the seals, however, Brembo doesn't say this in their literature and I've used it in Brembos for years with no ill effects.

I do agree that this contamination should be followed with a through cleaning and perhaps seal replacments if the emulsion can't be cleaned. But the new seals that you would be using would work with either brake fluid type.
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You are correct with your DOT 5 comment of reverse compatibility and the seals - we are talking the other direction. The damage to seals from DOT 5 (my thoughts) is most likely due to the non-lubricating characteristic and/or non-water absorbing (more corrosion) characteristics of DOT 5. I know of a few master cylinders that are not DOT 4 compatibile - I actually have one of them on my bike.

On the note of Brembos - in an older post I talked to Brembo engineer and DOT 5 is absolutely not a problem (as expected) and HD used DOT 4 for cost savings reasons and liability reasons since the average joe does not maintain the bike correctly and DOT 5 requires maintenance.

I am a big advocate of DOT 5 because it does not eat paint/plastic but the downside is higher maintenance.
 
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#20 ·
RODent said:
HD used DOT 4 for cost savings reasons and liability reasons since the average joe does not maintain the bike correctly and DOT 5 requires maintenance.
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I'm not sure where you get your information and I suspect you are throwing the term "engineer" around rather loosely.

As I understand it Harley went to DOT 4 when they began conversion to Brembo brakes for 3 reasons,

1. Because Brembo recommends DOT 4 (not that DOT 5 won't work but the recommend DOT 4)
2. Because DOT 4 performs better
3. They knew they were going to ABS at least 3 years ago and DOT 5 is not compatible with ABS.

I doubt it was as simple as to save money and liability exposure. The ONLY reason for DOT 5 to have EVER been introduced into a motorcycle is because it doesn't harm paint. There is no other viable reason to use it IMHO.

Also, there is no difference between a DOT 5 seal and a DOT 4 seal BUT, once either seal has been exposed to a fluid it is REQUIRED that you replace it if you change fluid types. I don't agree with the system flushing quick fixes, a proper move from DOT 5 to DOT 4 requires replacement of all lines and seals and a thorough cleaning of all master cylinders and calipers.

Seals are cheap, my life isn't!
 
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