Brake line contamination

[jdizon]

Switching up front and rear brake systems but I would like to re-use my existing brake lines. The lines I got are some quality lines from http://magnumshielding.com/ . I'm wondering what is the best procedure to flush clean lines before installing on my new master cylinders/calipers? The new MC's also are using different DOT brake fluid and I don't want to risk contaminating them. Any ideas? Don't want to spend another arm and a leg on new lines. Thanks.

 

[jd750ace]

You can flush them with clean fluid. It has some detergency to it. You might go with flushing the snot out of your old kit, let it sit overnight, then flush it again, then change the components. When you have clean non cloudy, no chunks flow on the old rig, fill the new caliper as full as possible with fresh fluid, connect the line at the caliper, then go on with your new master and bleed.
If you are going from DOT 3 to DOT 4 there's no contamination issue, but if you go synthetic (DOT 5) it's common to flush the system with denatured alcohol first, with complete disassembly and cleaning of the components. Seal compatibility is no problem, but it's said (I have never seen it personally) that mixing 3 or 4 with 5 results in a slimy gel.

 

[jdizon]

Thanks for detailed info. The new master for the front is Dot 3 or 5 compliant. The old system was using DOT 4. Probably going with DOT 5 with the new front MC.

 

[jd750ace]

While there are "published" advantages to the DOT 5 (Notably for custom work, it does not attack paint!) I have never converted one to it.
Sounds like an alcohol clean and flush for the lines and the caliper. Get technical grade alcohol for this, such as denatured alcohol from the hardware store, and make sure it gets completely eliminated before re-assembly. Blow everything clean with an air nozzle and set the parts in the sun if possible to warm them. It helps ensure complete evaporation of any alcohol traces.

 

[jdizon]

Thanks ja750ace! I appreciate the advice. To be honest not really sure the advantages and disadvantages of Dot 3 vs 5. I'd probably should google it but I was leaning towards 5 just because it sounds like the new and improved lol!

I'll pickup some denatured alcohol and start cleaning my lines.

Thanks!

Johann

 

[5twins]

Honestly, I wouldn't do the switch. I did it years ago to one bike but the advantages just don't offset the cost in my opinion. Yes, DOT5 costs lots more than DOT3-4. And they've improved the DOT4 to the point that the DOT5 really holds no advantages performance-wise.

 

[jdizon]

5Twins, Is there a performance difference with DOT 3 and 5?

 

[5twins]

Maybe there is, but I don't recommend using the 3. 4 is "hi-test" 3 and doesn't cost much, if any, more than 3. I'd use the 4. Your new MC recommends 3 or 5. 4 is relatively new and basically just a better version of 3. It's the same base chemicals, just a better version. It should be totally compatible with your new MC. Your instructions or the stamping on the MC may have been done several years ago before DOT4 came along, that's why it's not mentioned.

 

[jdizon]

Maybe there is, but I don't recommend using the 3. 4 is "hi-test" 3 and doesn't cost much, if any, more than 3. I'd use the 4. Your new MC recommends 3 or 5. 4 is relatively new and basically just a better version of 3. It's the same base chemicals, just a better version. It should be totally compatible with your new MC. Your instructions or the stamping on the MC may have been done several years ago before DOT4 came along, that's why it's not mentioned.

Awesome! and Your Correct, I was just going by the stamping on the MC. If I can use DOT4 than I'll continue to use it with the new MC. The MC I am using is the recommended brembo MC to work with my caliper. Thanks for your help.

 

[retiredgentleman]

I recommend Dot 4..................my Brembo calipers love the Dot 4

 

[jd750ace]

I run DOT 4 in all my bikes.

 

[XSLeo]

Why not use brake cleaner in a spray can to flush out the lines? If you can use it to clean calipers and M/C's it should work on the lines.
Leo

 

[jdizon]

Why not use brake cleaner in a spray can to flush out the lines? If you can use it to clean calipers and M/C's it should work on the lines.
Leo

Never thought of that. Anyone done this?

 

[I am Carbon]

hey jdizon,I've never done it , but I would think it would do a good job.
Brake parts cleaner is easy on rubber parts.
I would use it for that.
I use it to clean other things under the hood it has never messed up any electrical components that I've used it on.

 

[jd750ace]

Sounds fine now that I think about it.

 

[jdizon]

Sounds like DOT 4 and brake cleaner to flush lines is the way to to! I will get it done one of these evenings.