question about 83 brake systems

[timgray]

I was investigating how to bleed the brakes on my 83 and am completely confused. Everyone has mentioned that the rear brakes are bled at 3 places, yet if I follow the lines I can only find the lines to the rear and then to the front, Nothing else. At the foot pedal I see the master cyl, the resiovoir, then the lines split to the front and rear. Hard line to the front and a flexible to the rear.

 

THEN I have this wierd thing on the front brakes. You have a caliper, then a second hose going to the front of the fork on each side that also has a bleeder and for the life of me has no function. Unless there is a way for fork compression to push on the brakes.

 

Where is this mythical third bleeding point in the back brake system? Anyone have any details on the 83 bleeding proceedure?

 

Thanks all! when I get some details and run through it, I'll take a bunch of photos and write up a how-to for dummies so nobody else has to stumble through this. Here's hoping I dont shatter the resoivoir when opening it.

[Venturous Randy]

Tim, you actually have about 4 bleeding places on an 83 that are associated with the rear brakes. You have the bleeder on the calipers and you also have the bleeder on the anti-dive unit on the front of the fork. The anti-dive on the 83 uses brake fluid pressure to change the valveing on the strut to keep the front from diving during brakeing.

The other bleed position is up near the tripple tree where the the steering swivels, but there is not a bleeder. You would have to break the line loose near the top. Most don't do this. The later 1st gens actually have a bleeder near the top.

When bleeding the brakes, make sure you do not run out of brake fluid, as the reserviors are small, and do not over fill them when you are done as it can cause your brakes to get hot and lock up.

RandyA

[Snaggletooth]

Ok...here we go. I got really good at this one. LOL!

 

Make sure rear master res. is full. The 1st point of interest is the "meter valve". That is mounted just behind the right side on the frame behind the steering head. Follow the brake line and your fingers will find it. Tight with the fairing on but can be done. Some had a bleeder on them, some not. If not just wrap a rag around it and crack the brake line when the pedal pumped up. Tighten it before releasing the pedal just like a bleeder. Repeat as needed. Now go the the left front caliper and repeat the bleed process. Pump, bleed, pump, bleed until clear fluid and no bubbles. Now follow that line from the caliper to the anti-dive valve on the fork. Repeat process on that again. (The anti dive valve actually transfers pressure to the forks. As you apply pressure to the brakes the pressure transfers through the brake fluid pressure through the valve to become pressure to the fork oil, causing the fork tube to extend slightly reducing bottoming out or dive.)

 

Ok now to the rear caliper. Repeat the bleed process there. Don't forget to keep an eye on the master fluild level through all this. And DO NOT top off the master. It needs room for fluid to return to it through back pressure so leave some room. I fill mine with a ......

 

DO NOT LAUGH......

 

turkey injector. One with the big needle. Yep! It works good. Fill the master and then suck a little out. If the master is over filled it can cause the brakes to drag heating up the rotors and cause a lock up until they cool off.

 

So there ya got it. (1st) highest point in the system. (2nd) farthest points in the system. (3rd) closest point in the system.

 

Now.....be warned. It might take a while. Some have found it useful to let the bike sit over night to let the bubbles in the lines rise to the highest point (meter valve)

before bleeding. And when your done bleeding.....check the free play on your pedal adjustment.

 

Keep that fluid off the plastic for sure. Not good.

[timgray]

AHA! That makes sense!

 

I will tackle this later this week. and let it rest for a day, then re-do the bleed process.

 

How do you keep an eye on the level in the rear Res? Also should I simply run a Whole lot noew brake fluid through to change out all the old stuff in there? It's probably the same fluid they added in 1983 when the bike was built.

[Snaggletooth]

Yeppers..........fill the master and flush all the lines until you get clear fliud from all of them. The old stuff can be dark and dirty looking or just milkly looking from mositure. If you get adventerous and pull the master off the bike and open it up you might see a lot of grunge.

 

And you know to take it easy on the filler bolt on the master. A little sweet talk should keep everything in one piece. A few quys have split the masters wide open when they gave it a good shot to loosen the bolt. I like a 3/8 hand impact for stuff like that. A couple of taps to the clockwise, and a couple of smacks to the counter clockwise.

 

And you do realize what you have started right? First the bleeding of the brakes, then the rebuild of the calipers, then the replacing pads, then on to the braided SS brake and clutch lines, and then just when you are almost where you want to be you will start thinging about changing out the forks, rotors and calipers from a late model do you can REALLY stop better.

 

Oh have ya done the Progressive fork springs yet? Just kidding. Having an old bike is not addictive at all.

[timgray]

All that is already on the list... new Pad's showing up in 3 day,Got the springs waiting for later next month, I have a spare rear Resoivoir I bought lat year getting ready to go in case I blow mine apart. Someone already did that on this one, they welded up the all the cracks, I might just take it out completely and clean it out just for fun!

[Snaggletooth]

There ya go! Ya gotta a plan.

 

Like I said when I first joined this site. I'm not rebuilding an old bike.......I'm building a new one.

 

Have fun.