So it was time to replace the rear pads, which I have done before on my '04 Dyna and it is a fairly easy job so I didn't bother getting the manual out for the Ultra. So yesterday, I put the bike up on the stand, confirmed the DOT 5 fluid by observing the upper (front) master cylinder cover, pulled the rear master cylinder cover, then pulled and replaced the pads. No problem. However the master cylinder was a little low so I topped the reservoir off with DOT 5 fluid. Only when I went to put the master cylinder cover back on did I see the DOT 4 written on the cover. My front master cylinder says DOT 5!!. I did about a 30 mile ride afterwards and all was fine.

Now, after going thru my manual I see DOT 4 all over the place. I think the original owner replaced the front master cap with a chrome one from another bike and didn't care that it said DOT 5.

So I've put about, at most 2 tablespoons of the DOT 5 in the system but I doubt it matters how much, I know they are incompatible and being a braking system I know I can't ignore this. So my question is, did I already damage the seals etc. or can I flush and re-fill with DOT 4?

Also, any tips on the flush. I've heard about using IPA (isopropyl alchohol not India Pale Ale...that comes later) or what about Brakekleen or some other product? Any tips appreciated on the flushing procedure. The manual doesn't really discuss a flush. Only a complete brake system overhaul.

Thanks guys,
Dan

 

I would flush it out with Dot 4, Just saying

http://www.tccoa.com/brake-fluid/

http://auto.howstuffworks.com/auto-p...ake-fluid1.htm

 

With so little Dot 5 involved I think I'd try flushing first. Siphon all the fluid out of the reservoir first, then flush with a lot of fresh Dot 4. I don't think the Dot 5 will harm the seals, but mixed with Dot 4 it forms a jello like substance. I'd keep a close eye on the brake for a while after the flush. If it has problems it's not really all that difficult to rebuild.

 

Just flush it though and refill with DOT 4

 

I would just flush it out with DOT 4...pull a full bottle through and you should be good...just keep an eye on things after that.

 

You really need to suck most of it out of master cylinder and refill, Open the rear bleeder and slowly pump thru 3 or 4 refills not letting front cylinder go dry. Then snug bleeder and pump to get a firm lever and attach your bleeder hose to it in submerge end in about 1" of fluid. Then break bleeder and when lever sinks to bottom re-snug bleeder and pump to get a firm lever. Repeat till master is low and refill and repeat to insure you are seeing no bubbles. DOT 5 is good stuff but ABS forced Harley to go back to DOT4 across the whole Harley line. Sort of like mixing oil and water to combine them. The goo may later cause you piston boot to soften and leak.

 

So the consensus seems to be that no damage is done yet to seals or other components so I will follow the advice and just flush thru several cycles of DOT 4. I was afraid I would hear that the damage to seals could already have been done and I don't want to have to replace the entire system.

Thanks guys.

 

get some speed bleeder bleeding valves they make it so you dont have to open close open close ect

 

And it pays to read up on the procedure before you assume you know what you are doing. At least that is how I approach each project.

 

I'm sure he needed that ????