Ok, I made a big mistake. Putting a new rear caliper on the bike, I mistakenly put DOT 4 in my DOT 5 system. [sm=badidea.gif]

Now I need to get it out. The dealer tells me to get as much as I can out of the reservoir the pump the rest through the system. Sounds simple enough. I've read in other posts that you need to clean the system with a solvent but it doesn't say WHICH solvent. Would I use break cleaner through the lines? What will get the crud out of there?

I was also thinking about low PSI air pressure to blow the rest of the crap out of there. It makes sense (to me) that the air will push the junk out of there.

The good news, it has only been in there for a few days with only about 10 miles of riding. Well, I hope it's good news.

Which is worse, putting DOT 4 into a DOT 5 system or putting DOT 5 into a DOT 4 system? Or are they equally as damaging?

Thanks in advance.

 

Similar experience......A couple years ago, I purchased my used Heritage Softail and found out the hard way what happens when fluids are mixed. Seems the yahoo I bought it from mixed the fluid and when I was out on a ride, the front caliper locked/seized with me on it....ruining part of the brakes. Needless to say the bike leaned over, but the front crash bar saved it from any damage. I recommend that either you trailer it to the shop or flush the system before you ride it any further......it will seize, it just needs to get hot enough. I brought mine to the shop and they flushed the system, but I am not sure what they flushed it with. It was only around $100 or $150 to fix/replace the damaged brake parts and to flush the system. No problems since. Hope this helps.

 

harley198, do you have a DOT 5 or DOT 4 system?

 

I dont think you should use brake clean inside your brake system. If it were my bike I would do as the dealer suggested and then flush the system several more times using new DOT 5 brake fluid each time.......................BG

 

My 91' uses DOT 5

 

My 91' uses DOT 5

 

Use a turkey baster to empty out the master cylinder. The use a vacume pump to flush about a quart of DoT5 through the system.

 

Problem is; DOT 4 is Glycol base like antifreeze and does not mix. You now have got to flush the system using DOT 5 after draining all you can from the master and lines.

 

A Google search for "cleaning brake system with denatured alcohol" turned up some promising results.

It looks like denatured alcohol will not harm rubber seals and will cut the crud from the DOT 4&5 mix. D.A also dries without residue.

Other than the HD dealer, AutoZone is the only place that carries DOT 5 in my area (Las Vegas). So tonight I'll start the process.

1). Remove as much of the fluid from the reservouir as I can.
2). Disconnect the brake line banjo from the caliper
3). With compressed air, blow out the lines from master cylinder to banjo
4). With the banjo disconnected & bleeder opened, blow out the caliper
5). Reconnect everything
6). Run denatured alchohol through the system to flush out the crap
7). When running clean, one more shot of air through the system to ensure it's dry
8). Refill & bleed

I'll be sure to use tubing and a collection device to keep the crap from blowing everywhere.

Instead of filling from the master cylinder backwards I'll try the syringe method of filling through the bleeder forward. From what I've read and seen, it will virtually eliminate the air from the line as it's pushing the air out through the master cylinder.

Any comments?

 

Ultravista, I use a new (never had oil or anything else in it) leaver type oil can to pump the brake fluid back into the ststem. After system is thoroughly clean attach 1/4" fuel line rubber hose with 2 hose clamps, 1 on the bleeder and the other on the oil can. Open bleeder 1/4 turn and pump slowly till fluid fills the master cylinder. Tighten bleeder and you should be good to go................BG