dot4 fluid explosions?

[mountain thumper]

so way back i bought a " flavor injector"(think steroid syringe on steroids!) to bleed the clutch on my 07, which uses mineral oil(laxative lolz)
the syringe worked excellent for the reverse bleed!
so now shes gone, and i have jeep's old 250, which uses dot4 brake fluid in the clutch.
cleaned up the old "injector" put dot4 in it, went to the loo, came back and it had shattered? i thought it fell.
so after searching for 2 weeks, i finally procured another(every store in town has been out for this time!)
so i fill it up, bleed the clutch, works great!
but again i set the injector on the bench, as i took my test ride, when i came back, the new one had exploded!!!
i guess violently shattered is probably more accurate, but it doesnt sound as fun

has any one experienced this kind of reaction before? should i be worried about contaminates?

 

[widebear]

Its the alcohol in the brake fluid that is breaking down the plastic. If you use dot 5 which is silicon based and not a hydroscopic alchohol based compound you will also have a longer lasting fluid that is not effected by water contamination via humidity.Alcohol is for drinking not for brake fluid.

 

[mountain thumper]

could they just be swapped, or does the whole system need to be completely cleaned out first?
could you switch to mineral oil like on the newer bikes ithout a problem?

 

[Cruiser]

You cannot switch without rebuilding,, the o-rings are different.. o-rings for use with brake fluid have bad reaction to oil,, and also the other way around,, actually you can use brake fluid to "soften" hard o-rings and seals in say an old auto trans to get the vehicle to drive itself to auction.. or if you have a power steering leak on a junker brake fluid can soften and swell the seals up enough to get you home.. just you will need to fix more when you get there.. But if your 7 states away a power steering box and pump are cheaper than towing a 68 sedan de ville that far..

 

[Ud_luz]

I personally would refrain from DOT 5. While it's not hygroscopic like DOT 3, 4 or 5.1, if you do get any moisture in it the water will settle in the low spots of the brake system and cause corrosion. Not only that you could be running down a steep hill, heat up your brakes and suddenly have a partial or total loss of braking because the water suddenly boiled. This isn't an issue in race cars because of the frequent maintenance but in a dirt bike subject to wide ranging temperatures and heavy exposure to water it's a possibility.

We had a KTM 300 with DOT 5 suffer this in Colorado on a 3 mile long downhill in Aspen. None of the other KTMs suffered from this erratic braking on the same hill.

I believe the best policy is to bleed your system every year for maximum life.

 

[Cruiser]

DOT 5 is a PIA to use.. I would also recommend to stay away from it.. I worked at a shop that serviced postal vehicles and some of the fleet of grummun "vans" used dot 5,, issues out the wazu from corrosion to locking up to leaks on almost new parts.. a good 3 or 4 is better for our applications any day..

 

[Cruiser]

And yes BF should be changed yearly,, in any and all vehicles.. its photo sensitive and hydroscopic.. and flushing out the fluid yearly will help the calipers working smoothly..