DOT5 brake fluid in AJP cluch MC

[alecsstefan]

Hi, I'm planning to use the AJP clutch master cylinder to connect it to the rear break of my 07 EC300. What do you think about using dot5 brake fluid? Will it damage the clutch master cylinder seals? On the clutch MC is written "use only mineral oil". I have a rekluse clutch on my bike and want to make a lhrb setup along with a thumb clutch using a magura bicycle brake.

Thanks,

Alecs

[dank]

hmmmm. my MC on my 03 says DOT4 or mineral oil, so im surprised that yours doesnt. i think that DOT brake fluids can move down but not up, (i.e, you can use DOT5 where you can use DOT4, but not DOT3 where you use DOT4.) but i dont know about mineral oil. if it says just mineral oil, you will probably be best off using mineral oil, and not risk breaking something. you could call AJP and see what they have to say also....

[stainlesscycle]

don't do it.
dot 5 is incompatible with everything not marked dot 5.
dot 3 and 4 interchange.
to the best of my knowledge, mineral oil can be used in dot 3 and 4 applications. dot 3/4/5 cannot be used in mineral oil applications.

[GasTimppa]

If it says mineral oil, you can't use any brakefluid that is not mineralbased. o-rings and rubber parts that are made to mineral don't endure brakefluid and in the opposite direction too.

My earlier ec 200 had "dot clutch" and once I haven't got any "dot fluid" available when I changed clutchfluid. So I used mineral fluid ment for newer Gassers.

It worked well - for one ride... Then next morning I was suprised when my fluid reservoirs rubber was swollen twice as it's normal size. Same happend to O-rings in both clutch cylinders.

I asked our local dealer if fluid is reason for swelling and he said that that's the point. Rubber parts materials are different.

[jostby]

DOT5 is synthetic and the seals are specific for its use. You need to stay with the mineral oil. I think you can convert to DOT4 if you change all the old seals first.
You can use DOT3 or 4 interchangeably. DOT 4 has a higher boiling point. I have boiled DOT 3 in bikes though so it's not wise to use.
The nice thing about using DOT4 or mineral oil is it's easy to get in an emergency. Try finding DOT5 at a backwoods store sometime.

[jiauka]

Any industrial hydraulic oil, dexron II/III or even SAE 10 is fine for you.

As a side note, DOT 5 is useless and almost impossible to find, DOT 5.1 is a whole different stuff and it's a good direct replacement for any DOT 3 or 4 device, but NOT in your clutch, use hydraulis oil or dexron.

have fun,

j.

[alecsstefan]

dexron II/III looks to be a mineral oil, will it be compatible with my rear brake slave cylinder?

[jiauka]

Originally Posted by alecsstefan

dexron II/III looks to be a mineral oil, will it be compatible with my rear brake slave cylinder?

NO, NO!!!, your rear brake has DOT4 for sure, use either DOT4 or DOT 5.1,.

For your CLUTCH!!! dexron II/III is fine.

have fun,

j.

[alecsstefan]

I want to connect the ajp clutch master to the rear brake slave. I've heard of a guy using dot5 silicone brake fluid when he connected his magura clutch master master to the rear brake slave. The magura was build to use mineral oil. He stated that dot5 brake fluid does not damage seals build for mineral oil. I was wondering if anyone tried this combo on ajp without damaging seals.

[dank]

ok. my 03 has the ajp master cylinder. on the cap it says use DOT4 brake fluid. on the front brake it says DOT 4 or DOT3. on the reservoir for the rear brake it is DOT 4. so would you be better off finding a used master cylinder that runs DOT4 brake fluid that risking screwing up your system with different oils? because it may cost more in the end to buy new parts for what you have if you ruin them with the wrong fluid, than it would to find a part out bike and get the master cylinder and hose. just a thought. i apologize for the error in my previous post.