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Discussion Starter · #1 ·
Hey folks, I just recently purchased my bike (thanks to encouragement from this community) and I'm going to start the process of tinkering with it so I can learn a thing or two about mechanics. The item that I'm likely going to get started on right away is the master cylinder. I don't know if there is anything "wrong" with it, but I can't see if the reservoir has any fluid at all. The plastic is so old and weathered that it is just a deep white color that does not allow light through. It does look as though it may be half full but when I move the handlebars around, that apparent line of liquid doesn't rise or sink.

So, I have a few questions:

1. How challenging will it be for someone with zero mechanical inclination to replace the master cylinder?

2. Is this a serious enough issue that I have to stop riding until it's replaced, or is it okay to keep riding? I don't know what the result of a dry reservoir would be. Sudden brake failure? That sounds bad. Gradual decrease in braking effectiveness? Much less bad, but still something to attend to sooner than later.

I have thought about just opening up the top to check the fluid level, but I think there's a 60/40 chance that once it's unsealed, it won't be going back on.

Any advice is appreciated.

Cheers,
Ish 20180416_210726.jpg
 

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1 Master cylinder replacement is relatively easy and we can talk yoo through it, and the subsequent bleeding.

2 If concerned about sudden failure due to this manhandle it a little. If it holds up to that it will hold up for a while yet.

3. Do not be tempted to employ bleach. It causes a change in the plastic with consequences similar to decades of UV damage. Which is where you came in.

That doesn't look too bad. At their worst, the plastic surface begins to look sort of granular.
 

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Mine's a bit like that, but shining a torch through at the side I can see the level clearly.
 

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It would only be a temporary solution but you could try rubbing a bit of oil into the outer surface. Sometimes that can fill in the little cracks that cause the whitish appearance so that you can see through it a bit better.

At one time replacing the plastic reservoir was pretty common on this forum (or maybe its predecessor?) but these days you can get a complete better master cylinder from the aftermarket for about the price of an original reservoir.
 

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Mine looks like that and when it is filled with fresh fluid, you can see the level since it is darker than the rest of the plastic.
 

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Discussion Starter · #7 ·
Thanks everybody. I definitely plan on replacing it at some point for cosmetic reasons but not being able to see the fluid level got me thinking I should prioritize it. I'll take a high powered light to it tonight and see if anything shows up. I tried that yesterday in a shop and didn't see a thing but maybe it'll come through more out in the dark. If I open it up to check the levels (and maybe fill) how cautious do I have to be of falling bits of plastic getting into the reservoir? Clearly I'll try to avoid it, but are we talking about walking a tightrope with no room for errors?
 

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Discussion Starter · #9 ·
Thanks, I have some spray sitting around here someplace. I have heard of JIS but had you not reminded me I would have been all set and ready to go before taking a close enough look at the screw head to realize I needed another trip to the hardware store.
 

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If the screws are corroded in place - you need to give them a firm tap with the appropriate screwdriver to break the rust gremlins to be able to undo them successfully. Once removed it should just require a top up or replace the fluid - depending what you see.

It can just be a matter of absorbing the old fluid or removing it mostly with a syringe - then refilling with new fluid - but if going that far - I would probably flush new fluid through the system as your first maintenance task. Remember to cover all your painted parts anywhere near the master cylinder to avoid damage to your painted surfaces. Or keep a good supply of clean water nearby to wash off any stray drops immediately.

Have fun
 

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While we're talking about the brake, a couple of things come to mind:
1) Unless there is a leak the level in the master cylinder is the easiest way to tell how worn the pads are. The pads normally rest so that they are almost touching the disc and as the pads wear away the piston(s) rest farther out of the caliper. This means that there has to be more fluid inside the caliper to make up for the volume of piston that is outside and that means that the level in the reservoir will decrease as the pads wear. If you top up the fluid you won't be able to tell how worn the pads are without looking at them.
2) That said, brake fluid in a system with rubber lines should be replaced every 2-3 years (largely because of tiny particles of rubber that contaminate the fluid, turning it red) and the rubber lines should be replaced every couple of fluid changes (5-6 years). If your bike has rubber lines there is a very good chance that they are original. Its up to you if you want to risk your life with old lines but I would replace them with braided stainless lines (which last forever unless physically damaged and also increase the fluid change interval) and probably replace the pads, master cylinder and all of the caliper's the rubber parts at the same time.
 

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Discussion Starter · #12 · (Edited)
Well I found a place locally that has the master cyclinder for $40. I'm pretty sure it's the same as the attached pic. I'm gonna go there after work today and pick that up (unless anybody thinks it's too cheap of a product). While there I'll also be getting an oil filter and either some oil from them or a gallon of O'Reily's in house brand 15w-40 for $15.

Out of all that Sidecar Bob listed, what has to be replaced at the same time as the master cylinder and what can be done at a later date? Is it a matter of having everything disassembled and just knocking it all out at once so it doesn't have to be disassembled again and use up more brake fluid? I'm just worried that if I try to undertake too much in one day, I won't finish up. I live in Portland OR, so the chances of it raining sooner than later are pretty good. I'm therefore reluctant to undertake any kind of project that can't be completed in one sitting.

Until I found out that I could get a master cylinder tonight, my plan for the weekend was to replace the oil filter, flush the coolant (according to this forum cheap pre-mixed green will do), clean/replace the spark plugs, blow out the air filter and eventually replace it. But all of that can be done piecemeal over the next couple weeks and, since I'll have several hours, I'm definitely interested in doing a more comprehensive project like the brakes tomorrow.

- Is there anyone out there who could list the order in which I should be doing this brake work?
- Are there any videos out there that give a step by step layout? Or some posts that can walk me through it?
- Other than the JIS heads, are there any specific tools I'll need that didn't come with the bikes tool kit? I have the basics: wrenches, sockets, vice grip, crescent wrench.
- If I hold off on the brakes and do the aforementioned stuff, is there another quick and easy project I should try to squeeze into the day? replica_honda_brake_master_cylinder_motorcycle_80s_45500_463_601_1__35042.1397861500.750.750.jpg \
I'm excited to get into this stuff. Tomorrow is supposed to be a 60F partly cloudy day and around here that's the equivalent of warm and sunny.
 
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Its your life so you have to decide how much risk you are willing to take. I wouldn't ride a bike with 40 year old rubber brake lines anywhere where I might need to stop in a hurry, which pretty much means anywhere these days. I suspect that the master cylinder you are getting is the same as the ones you can get on eBay. The eBay ones are about half the price but some are crap and some are great and you can't tell from the pics. I bought a couple of the crap ones and the rubber parts on the first one failed before I got around to installing the other one so I bought the ones Murray told me to (only about $2 or 3 more than the crappy ones), installed them on both of my bikes and they are still working perfectly several years later. Even in person it is hard to tell which is which. Hopefully if you are buying from an actual store it will be the good one or they will back it up if you have problems in the future.

The brake work is best done all at once. It doesn't make sense to replace the master cylinder and bleed the system this week, then replace the lines and bleed it again next week, then rebuild the caliper and bleed the system again the week after, You can replace the pads without bleeding the system but if you refilled the system the master cylinder will probably be too full when you push the piston(s) back into the calipers to accommodate the new pads.

To work on the bike you should have at least single hex metric sockets, metric combination wrenches (box on one end, open end on the other), assorted screwdrivers, pliers &c and eventually probably metric allen wrenches. Put the adjustable wrenches and vise grips in the back of the drawer and don't use them except on fasteners that you are 100% certain that you will be replacing after you get them out.

The Tom's Cycle Recycling YouTube channel has some good videos about working on brakes https://www.youtube.com/channel/UC0prOClnfgRF6zsWmLNYk8g (Tom is a regular at Naked GoldWings and knows his stuff).

Welcome to the world of antique vehicles. You may have thought you were getting a cheap old bike but at 37 years old it really is an antique and needs to be treated as such. I don't mean that you have to baby it (although some do) or that you can't use it as an every day driver (a lot of us do) but that it has had 37 years of unknown Previous Owners who may or may not have done the maintenance necessary for it to stay safe & reliable and unless you bought it for a garage ornament you need to go over it thoroughly from end to end and make sure everything is as it should be. If you haven't already done so go to the CX Wiki (link in my signature) and download the Factory Service Manual. Since you don't know the bike's service history (and you can tell from the brake lines that some things have been neglected) its a good idea to go through every service procedure in the book, regardless of whether your bike has the mileage the procedure is recommended at. Also, find the date codes on the tires and if they are over 5 years old or you see any cracking, checking or damage plan to replace them ASAP.

BTW: Welcome to the forum. Please add your location to your profile (see Forum Settings link in my signature). You never know, there may be a forum member near you who can help you figure out some of this stuff.
 

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Ish - let us know how everything goes... I'm getting ready to do some work on my front brakes as well (new braided line, pads)... I'm gonna try to keep the orig master cylinder but we'll see how it goes.
 

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Well I found a place locally that has the master cyclinder for $40. I'm pretty sure it's the same as the attached pic. I'm gonna go there after work today and pick that up (unless anybody thinks it's too cheap of a product). While there I'll also be getting an oil filter and either some oil from them or a gallon of O'Reily's in house brand 15w-40 for $15.

Out of all that Sidecar Bob listed, what has to be replaced at the same time as the master cylinder and what can be done at a later date? Is it a matter of having everything disassembled and just knocking it all out at once so it doesn't have to be disassembled again and use up more brake fluid? I'm just worried that if I try to undertake too much in one day, I won't finish up. I live in Portland OR, so the chances of it raining sooner than later are pretty good. I'm therefore reluctant to undertake any kind of project that can't be completed in one sitting.

Until I found out that I could get a master cylinder tonight, my plan for the weekend was to replace the oil filter, flush the coolant (according to this forum cheap pre-mixed green will do), clean/replace the spark plugs, blow out the air filter and eventually replace it. But all of that can be done piecemeal over the next couple weeks and, since I'll have several hours, I'm definitely interested in doing a more comprehensive project like the brakes tomorrow.

- Is there anyone out there who could list the order in which I should be doing this brake work?
- Are there any videos out there that give a step by step layout? Or some posts that can walk me through it?
- Other than the JIS heads, are there any specific tools I'll need that didn't come with the bikes tool kit? I have the basics: wrenches, sockets, vice grip, crescent wrench.
- If I hold off on the brakes and do the aforementioned stuff, is there another quick and easy project I should try to squeeze into the day? View attachment 161705 \
I'm excited to get into this stuff. Tomorrow is supposed to be a 60F partly cloudy day and around here that's the equivalent of warm and sunny.
That's the one in post #3 I think, it should be OK, better than a rebuilt one.
 

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Discussion Starter · #16 ·
Hey folks, thanks for all the great info. I'll post a write up of what I did and, if any new owners like myself care to know, how I did it. But I don't have a lot of time at the moment and wanted to get this quick question out there:

What is the name of rotors with additional holes in them? Anyone have recommendations, suggestions, or links to a solid product?

The day before I purchased this bike I posted on here looking for some advice and I received a lot of great encouragement to go forth with the purchase. The only thing that made me hesitant about buying the bike is that the front brake staggers/stutters. It still stops on a dime but it is something I definitely wanted to fix. The consensus seemed to be: start fixing up and/or replacing the braking mechanism; move from simple to more complex. Well while I was swapping out the master cylinder, a guy happened on by who worked in a shop for a decade. I told him about it and he checked out my wheel. Turns out my rotor is warped. So I'm looking to purchase a new(ish) one. He said that I should get one with holes in it because it will help with braking in the rain. Since I live in Portland, that seems like a good purchase. I'm trying to find them but don't quite know what to search for.

By the by, the master cylinder is working out great.

Thanks all.
 
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Discussion Starter · #18 ·

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I always assumed the drilling was just a weight-reduction thing done for racing, and then copied for aesthetics in production bikes... I didn't realize that it helped with wet weather.
 
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