Hi all

Purchased the bike of my dreams, a 1980 FLH. http://www.geocities.com/jammerjamesharmoni8/1980FLH

The problem I'm having is having to pump the front brake. I cleaned and honed the cylinder in the master and installed a new kit. Bleed it and it seemed alright. After a few weeks, it is back to having to pump it again at "every" stop. The cheesy manual I own, states DOT5, synthetic right? Could this be a problem??? If not any suggestions would be much appreciated.

Thanks
James

www.geocities.com/jammerjamesharmon

 

DOT 5 is correct. Try rebuilding the caliper. What kind of brake line? Is it possible you still have air in the system?

 

Brake line is new, non rubber, could still be air. Have not rebuilt the caliper. Thanks for your help.

 

DOT 5 In a 1980???? How did we arive at that other than the cheesy manual? If it is the origional equipment on the bike and you did not rebuild the caliper, not a good move with the dot 5. IMO Those systems ran 3 or even 4 but 5 didn't come out for a time after that bike was manufactured. A lot of times the seals and that are not compatible when changing fluids to a different dot and new style seals must be installed throught the system to be compatible with the DOT 5 .

If you mix the fluids, your system will be contaminated and the result will be globs of congealed fluid in the system.

https://www.hdforums.com/m_68186/tm.htm

https://www.hdforums.com/m_88878/tm.htm

 

My '78 factory manual called for DOT 5, IIRC. I don't have the FLH manual, but I just checked my '70 - '77 & also my '78 - '79 Sporty factory manuals, and they both call for DOT 5. The master cylinders and calipers were the same on the Sporties & Big Twins, so I'll stand by the DOT 5 call!

 

My manual is a Clymer, but shoot the factor manual says so too................ Very possible former owner put the Non DOT 5 in there, I guess, I'll tear into the caliper, probably should go ahead and order the rebuild kit now. Thanks all the the great advice........

 

I stand corrected here, what I didn't realize is how long that DOT 5 has been around, I found this to back up what you say...

The development of Silicone Fluid (DOT 5) began in the late 60's by General Electric (Head of R & D on this project was Dr. Torkleson). It was orginally developed for the Jim Hall Chaparral Racing Team as a solution to the higher temperatures and extreme conditions being realized in Can Am racing. Hall had observed, in such races as the Daytonna 24 and the Twelve Hours of Sebring, the brake discs (rotors) glowing from the extreme temperatures. This led to the involvement of GE and ultimately, the development of Silicone brake fluid

 

I own a 76 shovel, that is the year the harley switchted to DOT 5. If you have a 76 you MUST check which flued to use (usally on the master cap) any thing after that will be DOT 5. I had a similar problem in a car when I just honed the master cylindar and replaces the seals. I tried to get away cheap, and was lazy and did not check the bore. It seems that it had been rebuilt before and the hole was too big. Now If I rebuild I will bore and sleeve it.