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Discussion Starter #1
In my continuing process of resurrecting my 1981 cx500D and based on Side Car Bob’s recommendation, I’m replacing my original brake line with ss line. Also replacing the mc. I also plan on cleaning the brake caliper and replacing pads and brake fluid. So my question is the original line has what I’d call reinforcement rubber over the line in certain areas. Does that need to be pulled off and put on the ss line? (If even possible).
This forum has been so helpful throughout this process. Thanks in advance.
 

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That extra layer on the original lines is probably there to protect the rubber line from wearing away where it rubs on something. If your new line is covered with plastic it probably doesn't need the extra layer but if you have a bare stainless braid you might think about something to protect what it rubs against because it can file away aluminum and saw through plastic.
 

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Discussion Starter #4
OK. Got the line a routed. Another question: Do the banjo bolts have to be in any particular orientation relative to the wholes lining up? Just use the copper crush washers that came with the ss line in front and behind the line fitting?
(BTW) The line is covered in a plastic coating so I'm not concerned about possible friction interference.
Thanks again for the hlep.
 

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Inside the banjo fitting there is a groove that runs all the way around; Both ends of the hole are likely to point at the groove, which is just fine.
And yes, one copper crush washer on either side of the banjo fitting.
 

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Discussion Starter #6
Hopefully my final question on my brake project. MC, brake line and rebuilt caliper are all ready to put brake fluid in. Do I just fill up the MC and start doing a bleed procedure?
 

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In theory yes. In practice you may need to bench bleed the master cylinder before you can get it to pump fluid into the line.
It is easier to vacuum bleed brakes than it is to pump fluid through with the master cylinder. There are some really good vacuum pumps on the market for that but for most of us amateurs this one does the job nicely Brake Bleeder and Vacuum Pump Kit
 

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Bob, I'm sure meant to bench bleed the master cylinder, not the caliper. You can bench bleed the master cylinder by simply using your finger. Ask if you need further instructions. As Bob said, the vacuum pump method is by far the easiest. I don't have one so I don't use one. I have never had a problem bleeding the brakes on any vehicle the old fashioned way so I've never invested in a vacuum pump. However, I do have a vacuum pump and gauges for a/c systems. I like a/c if I'm going to suffer in a car or truck!
 

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199659


I never had a lot of trouble bleeding the conventional way (except when other problems were involved) but vacuum bleeding saves a lot of time. I figure it takes me more time to set up the pump, clean it after and put it away than it does to actually bleed the brake and the whole process takes less time than conventional bleeding.
 

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Discussion Starter #10
Thank you all for this. I have a vacuum pump which I used to take the brake fluid out of the system. Not sure how to bench bleed the mc. It's on the handle bars with the brake line attached. Haven't attached the line to caliper yet. Do I vacuum through the end of the brake line? Also do I keep the mc cover off during this process?
Thanks again.
 

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As Doug said, bench bleeding the master cylinder is as simple as putting your finger (or thumb) over its outlet to act as a sort of 1 way valve to let the air out and gently pumping until you feel fluid pressure.
Before you bench bleed you should have the caliper mounted and the brake line attached to it and routed to the master cylinder and the banjo bolt & washers ready so that you can get the line connected fast to prevent any of the fluid from dripping/running out (don't let it drip on the paint!!)

BUT if you vacuum bleed you don't have to worry about that. With the caliper mounted and both ends of the line connected fill the master cylinder to a bit above the upper mark (leave the cover off for now because you will be adding more fluid), loosen the caliper's bleed screw, connect the vac pump and pump it a few times. As the level in the master cylinder decreases keep adding more until you see clear fluid with no bubbles coming out of the caliper. Then close the bleeder, fill the master cylinder to the appropriate level and replace its cap.
Squeeze the lever to confirm that everything is working. You might need to pump it a few times to bring the piston(s) into contact with the pads and push them against the disc but after that it should feel firm on the first aqueeze. If not turn the handlebars so that the master cylinder is at the highest point, tie the brake lever to the handlegrip and let it sit like that overnight to allow any trapped bubbles to rise.

Re "appropriate level": As the brake pads wear the caliper's piston(s) need to protrude more to press them against the disc, resulting in a greater volume of fluid being inside the caliper and less in the master cylinder. Because of that the level in the master cylinder decreases with pad wear, providing the best indicator of brake pad condition. If you fill it to the upper mark when the pads are new the level should reach the lower mark just about when the pads need to be replaced.
Because of that it is best to replace the fluid and the pads at the same time. If you have to change the fluid without changing the pads estimate the percentage of pad life remaining by measuring the pad and comparing that to what the FSM specifies and try to fill the master cylinder to a level that reflects that amount of life.
NEVER top up the master cylinder between pad changes because if you do the level will be too high if you need to push the piston(s) into the caliper for any reason (like changing the pads or removing the wheel).
 

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Wow.....you all sure make a simple process overly complex.

Use the KISS principle. Keep It Silly Simple.

Mount all the components.
Fill the MC, cap off. You may need to refill during the process.
Use your thumb to bleed the MC. Cover the pressure outlet with thumb, pump the brake lever. Soon fluid will squirt out around your thumb.
Install brake line to MC, do not connect to caliper. Bleed the brake line using the previous technique.
Refill MC as needed.
Connect brake line to caliper, open bleed port. Squeeze lever, hold lever, close port, release lever. Crack port while squeezing lever......repeat until fluid leaks out of port. Close port.
Refill MC.
Squeeze brake lever. Lever should be firm. If not, then repeat process at caliper.
 

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Wow.....you all sure make a simple process overly complex.

Use the KISS principle. Keep It Silly Simple.

Mount all the components.
Fill the MC, cap off. You may need to refill during the process.
Use your thumb to bleed the MC. Cover the pressure outlet with thumb, pump the brake lever. Soon fluid will squirt out around your thumb.
Install brake line to MC, do not connect to caliper. Bleed the brake line using the previous technique.
Refill MC as needed.
Connect brake line to caliper, open bleed port. Squeeze lever, hold lever, close port, release lever. Crack port while squeezing lever......repeat until fluid leaks out of port. Close port.
Refill MC.
Squeeze brake lever. Lever should be firm. If not, then repeat process at caliper.
Bob simply gave a lot more information than the bleeding process, all of which is good information that the OP may not already know. As far as KISS, bleeding with the vacuum pump is by far simpler especially since the OP already has the pump. I myself bleed the mc with my thumb as you suggested but after that I bleed the line and caliper together, not separately.
 

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Discussion Starter #14
All of you are awesome.
I'm a retired band and orchestra teacher that recently returned to teaching half time. Working on this cx500 has been therapeutic especially with trying to figure out how to teach remotely and via electronic devices.
Thanks lots!
 

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Discussion Starter #15
I did wonder about the old pads being so dissimilar in thickness usage. One side hardly any wear and the other almost used up. Is that normal? Done lots of car brakes and not seen that before
 

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Wow.....you all sure make a simple process overly complex.

Use the KISS principle. Keep It Silly Simple.

Mount all the components.
Fill the MC, cap off. You may need to refill during the process.
Use your thumb to bleed the MC. Cover the pressure outlet with thumb, pump the brake lever. Soon fluid will squirt out around your thumb.
Install brake line to MC, do not connect to caliper. Bleed the brake line using the previous technique.
Refill MC as needed.
Connect brake line to caliper, open bleed port. Squeeze lever, hold lever, close port, release lever. Crack port while squeezing lever......repeat until fluid leaks out of port. Close port.
Refill MC.
Squeeze brake lever. Lever should be firm. If not, then repeat process at caliper.
You call that simple? Every time you remove your thumb, air enters the system. You're, basically, bleeding 3 times.
Simplest, but time consuming, is tying the lever to the grip, overnight.
Vacuum pump is best, and quickest.
 
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