Do I bleed and remove most of the fluid first, change the brake pads first, or does it matter?

The bike has been sitting 25 years, according to the previous owner. I had a shop do the tune up and put new tires on. Now I want to tackle the brake system, even though I've never done them.

I've seen the bleeding vids on Youtube. Just follow those directions and keep adding fluid until it's clear?

Thanks in advance.
JB

 

Preferably, ya wanna clean any gunk/gum accumulated from the years of misuse. Since its wintertime ya may wanna pull the calipers apart & clean em up & have the discs surfaced or replaced along w/ whatever else, such as old dry, worn out brake pads, doesn't meet objective tolerances (by, repair manual). Its pretty easy--a few rags some brake cleaner, & some measuring tools, & etc, along w/ some patience gets it done.
There's a guy in the ....regularly around, at least since I've been here, likely, to help out when ya get in trouble.

Lots of luck to ya--Nice Bike

 

If it were me and I planned on using it I would break both lines from cylinders / calipers flush the lines and rebuild or replace it all. Just no telling what you will have any other way. The rubber internals are hard, you may have corrosion and until you tear it all apart you will not know. You either need to be real mechanical if you have never did it or get someone else.

 

The thing is with brake fluid, it's got a property called "hygroscopic", it absorbs water. Water, being heavier than brake fluid (and most other liquids) tends to migrate to the lowest part of the system, the lines and calipers. There it attacks the metal parts. I've seen rubber brake hoses plugged solid from the rust produced by this corrosion. So, yes, as the others have stated, definitely take it all apart, and plan for the worst. You may get lucky and not need to replace a whole bunch of stuff, but you'll never know unless you inspect it all. Be really critical when you look at the caliper piston bores too. Good light, and a magnifying glass will help you a lot. Any pitting, or deviation in those surfaces will mean trouble later, either a leak, or mushy brakes, neither of which is very comforting on brakes. I notice you live in Texas. Hopefully the drier climate has been kind to this bike!

 

Thanks for all the advice. Chunk,I'll definitely clean all of the brake pad areas, calipers and rotors when I do the pads. I dripped a bunch of brake fluid on the rotors, is that going to cause braking issues or can I just use brake cleaner or sandpaper on the rotors for improving the grip?

Today I just flushed the front dual brake system by bleeding from the bleed valves/screws on the calipers and adding new dot 5 purple fluid to the master cylinder until what came out was purple. Took me about 2 hour by myself to bleed both front brakes and get hydraulic pressure back to where it was.

The old brake fluid was in there was gold/light brown. It was quite a bit of work to do alone but I finally grabbed the syringe I use for injecting turkeys before frying and force fluid back into the lines.

Yes, I can see the effects of water absorbing qualities of brake fluid in the brake line connectors at the calipers. Rusted pretty good. Might be a good idea to replace them all pretty soon but thought I'd get practice flushing them in the meantime.

GRF000, the fluid was fairly clear, so I don't think there was a lot of corrosion within the brake lines themselves, just the external metal cable connections. But I'll have to replace the whole line eventually, or risk braking one when I likely really need it.

A Seabee, the calipers I didn't really get into today, but there is surface rust on the components that hold the pads. Likely the pistons are not in great shape, but I'll take apart in the next day or two and post some pics.

JB

 

I was not sure you had dot 5. My 04 has. Dot 5 changes from the purple to the straw after a while. Not sure why. However it does not absorb water or hurt paint but that is not to say some moisture got in there. However my bike is 7 years oil and I bleed all out good on my last pad change and it all looked good. I was thinking corrosion around aluminum pistons were they seal. Not necessary the line but I figured if you broke them apart you could get a better idea what you had just to be safe.

 

DOT 3/4 are glycol based. I don't know if the two are compatible or not. I'm pretty sure not, and the only to get all traces of the old fluid out is to disassemble everything and replace any seals or hoses that are hard/old/cracking. From what I remember about these two fluids it'l make the seals swell, and that's not good. Better read up on it. I do know at one point newer HDs used DOT 5 fluid from the factory. Also DOT 5 does not change color as it does not aggressively attract moisture. I'd check it out on the web and check with the HD dealership service dept.

 

Man this sounds like a cool project! Have fun!

 

You've done well to bleed the system after all that time! As mentioned, DOT5 does not absorb water, but over such a long time there is no knowing what may have gone on inside. Clean any fluid on the rotors off with something like white spirit.

You have done the right thing replacing the tyres, but I agree with grf000 and recommend you strip and inspect the entire system. If everything looks servicable inside I would then buy service kits for each caliper and master cylinder and replace the hoses. It is probably cheaper to use braided lines, which will also give you improved performance over stock ones.

 

I think, you are doin what is good enough, ya know. Replace the brake pads whenever ya get a chance they dry out due to weather conditions; old brake pads will bring your *** to a stop but they will wear quick & pretty soon your brake pad backing plate (generically, i speak) will begin digging grooves into the disc. Check all your rubber lines too, if the metal isn't shiny & new, well, no big deal so long as it is doing its job, it might haunt ya whenever ya wanna make greater changes but until then--most, would agree, if its not broke don't fix it--however, ya know, that's all your call. You're down in Austin & riding is good so get your stuff workin good enough that ya ain't gonna kill yourself & fix it up a little at a time--getting all the parts necessary before ya dig in will keep ya on the road longer than starting & having ta stop, waiting for a part.
Sounds good. Keep on, Keepin on!

By the way, ya need to use a quick evaporating fluid around breaks, such as break fluid--squirt some...see how fast it evaporates?...when ya get into rebuilding them calipers, I suggest cleaning everything (metal parts) w/ a good fast evaporating fluid & then rubbing a soft cloth (like a cotton baby diaper) w/ MEK, methyl ethyl ketone, usually get it at Walmart or hardware, because it has a lubricating quality to it, as well--especially good for carburetors also--just leave a nice dry type coat on it (like a rifle).

Also, oil eats/disintegrates rubber---get it? Its real stupid, just take your time w/ it.