Continuation of rear brake kinda hard The brakes are new and was to have been flushed. Yup it was flushed with Dot 3 or 4 come to find out. I`m not sure how big of a deal this might be but on a auto I`d be jumping naked on SOMEBODY BG We used to be a Mitsubishi car dealer and one of the guys used Dot 3 in a H&^5 I can`t remember what model it was but you wanna talk about a mess. IT WAS . Lines look good no kinks that I can find. What I noticed was that with the caliper off I can push the pedal a full stroke, the piston moved. Let pedal up, wait a few seconds and take another push (stroke) Pistons haven`t moved since. 2 more strokes no piston movement. It seems like the m/cyl is not taking fluid on to make a second or 3rd stroke. Reservoir cap off The fluid is clear amber and I ck`d with PO it does have dot 3 or 4 in it. He asked what difference would it make. Ummm Things that make ya go Ummm BG WP

 

Start with flushing what you have. Drain it, run some brake cleaner through it all, disconnect the line at the MC, open the caliper bleeder, hook up an air hose and blow it all clean. Fill with DOT5 and flush a bunch with that. See if it works. If you didn't get a bunch of black stuff (your seals) come out with the flushes and the brakes work, I thinkyou'll be OK, otherwise get some rebuild kits (seals) and rebuild the MC and caliper.

 

I have a jar of mixed dot 4 and dot 5, I shake it every week but it hasn't turned to jelly in a year....

I flush with meths when doing a dot swap, works fine :-)

 

DR Hess

With the age of the bike I`m gonna get the kits to rebuild the the M/Cyl. and caliper. Get things flushed good and go from there Thank you for your help Sir WP

 

Difference is the boiling point of the fluids, only thing DOT 4 will do is boil out of the system under constant hard braking. DOT 5 will stay on the job. Thus the reason DOT 5 is used in race cars and airplanes.

DOT 5 won't ruin your paint, DOT3/4 will or maybe.

 

I can count on one hand the number of times I thought mixing dot 3-4 with dot 5 caused a problem in an auto. With a good bit of varying degrees as to severity of problems we thought it caused. I`ll just feel better rebuilding the M Cyl and Caliper and getting it all cleaned up good. I do appreicate your help WP

 

but you cannot mix 3/4 and 5.... spanner 39 says he has a jar of it mixed with no problems .....I had it in my brakes lines and it was one unholy mess ....jelly everywhere and a hard as rock lever that wouldn't put the brakes on ...had to drain and flush all lines and disassemble all rubber parts to clean/replace even the master and then reload with 3/4
It looked like a jellyfish hab been in my calipers a translucent greenish colour ...after the cleaning and removing all rubbers and cleaning behind them ..it was fine .......
and even race cars are going away from using it as it doesn't work well at all temps just extreme temps

 

The difference is dot 3,4 & 5.1 are Glycol Based, DOT 5 is silicone based.

It is so common to find Harley with brakes not working simply because owners have added brake fluid without realising the differences.

A dyna I bought a while ago had this very issue, it can be sorted but does involve stripping the brake system down and cleaning all parts making sure all fluid is out. Then re-assemble and flush with the correct fluid, then bleed.

 

Have seen 3-4 flat eat some paints Thank you WP

 

Then re-assemble and flush with the correct fluid, then bleed

Dot 5 has not been easily found in my little city. So I`m told and the 2 supply store I ckd with yesterday say they don`t carry it. Ordering for me wasn`t even mentioned. I`ll ck with a couple of indys and a dealer a few miles away. With the age of the bike I`m thinking take things apart and reseal the master cyl and caliper Thank you Sir WP