ok, here is the situation...gave a friend my old bars and he installed them this weekend. during the swap he filled master cylinder and bled brakes with non-DOT5 fluid. he said the bottle said DOT3&4 (no, it wasnt DOT5.1). he has probaby put 100 miles or so on the bike since.

im assuming that his caliper is the same on my softail (his bike is a RK but not sure of year) with the bleed valve on top - so i would assume that he didnt drain all the DOT5.

getting differing opinions but would like to hear from those that know...

and looking for next steps. easiest option seems to be:

- clean out the master cylinder completely
- get new brake line
- clean out caliper and replace seals
- fill with DOT5 and bleed

or is there an easier solution that im missing?
is it possible that he bled the brakes enough and essentially converted his system to DOT4 and will have no issues?
and when would he notice any issues, if he were to have any? tomorrow, a month, 6 months...?

thx in advance for all the advice.

 

his brake fluid will jell and eventually destroy all parts, eventually brakes will not work. Take apart everyting and flush the entire system piece by piece including taking apart the calipers & M/C. No other choice.

 

thx for the response. couple more ?'s.

master cylinder seems easy but whats the best way to clean caliper?
and any seals or internals need to be replaced? or just a good cleaning?

ive given him another brake line to use but if he wanted to clean out his stainless one, could he do that and re-use it?

thx

 

You'll never get all the fluid out of the brake caliber without taking it apart. Calibers are pretty simple. The only moving part is the piston that pushes the brake pads together. Once off the bike you apply compressed air to the fluid intake hole and blow the piston out (keep you fingers out of the way as the piston will come out with a lot of force). Also place a shop rag into the caliber to cushion the top of the piston when it comes out. Check for jelled fluid or corrosion on the piston or inside the cylinder. A slight amount of corrosion can be cleaned up as long as there's no significant amount of pitting. Also there is a rubber O-ring on the piston so inspect or replace that as needed.

Then clean or flush everything, including the master cylinder and the brake lines, with denatured alcohol. Once that's all done you can run any grade Dot brake fluid you want (no matter what it says on the master cylinder cap) as long as you stick with it. Of course using what's on the cap makes it easier on the next owner, LOL . . .

 

What they said. Happened to me. Before I bought the bike, some knucklehead mixed em. One day the rear brake started to drag. Stuff had turned to glue. Rebuilt MC and caliper, new lines. No other choice.

 

Aww yes. the classic douche baggery of switching brake fluid just before the sell. glad I'm not the only one that has had that happen.

 

i knew it couldnt be as simple as running/bleeding a gallon of brake cleaner through the system.

almost sounds as if an easier/quicker fix for him might be disassemble all, buy a new caliper, running brake kleen down line and thoroughly cleaning out master cylinder.

what a master cylinder these days? $100 or so versus about $25 to re-build.