how do I take apart a 1981 master cylinder?

[happydaze]

I bought a used master cylinder on eBay. Cosmetically it looks great but the reservoir was full of rust and sludge. I tried to clean it out but nothing goes through when I squeeze the lever. I tried holding the lever down and blowing air through the hole in the bottom. No go. Is there a way to take it apart and clean it out?

Meanwhile my old master cylinder works but I can't get the cover off of it. 3 of the 4 screws have stripped heads now because they won't turn. I'm about ready to start intentionally destroying the plastic parts to get it apart.

I'm really having bad luck with these brakes.

Thanks for any advice.

 

[Brassneck]

You could try easy-outs to get the screws out...if all else fails, you could cut up the reservoir cover and use the cover from the one you bought...Assuming it's a stock replacement MC.

Did you buy the Ebay MC just because you couldn't get the screws out? Or for some other reason?

 

[happydaze]

Thanks. I have given up for today but I'll buy ez-outs tomorrow.

I bought the one from ebay because the one that was on the bike has cosmetic damage. If there's no way to fix the one from ebay I should try to return it. Otherwise it's an expensive used cover.

 

[Brassneck]

Btw, if the one you got looks better...probably just needs a rebuild. You can get a kit..and here's a great summary on rebuilding it.

http://www.xs650.com/forum/showthread.php?t=7862

 

[XSLeo]

The M/C isn't hard to tear down with the right tools. Where the lever pushes on the piston is a rubber dust boot. This comes off. Once off you can look down inside and see a snap ring holding the piston in.
A very long nose set of snap ring pliers are needed to easily remove and install this snap ring.
Once out the piston comes out easily, or should.
You should also remove the reservoir. Under the reservoir is a tiny bleed hole. If this hole is plugged the M/C won't work well.
There are threads on here that better explain all this, some even have pics.
Leo

 

[happydaze]

Thanks @Brassneck. That's what I needed to know.

I'm really starting to think that I should sell this bike though. I think my goal is going to be to get the brake to work and sell it. It needs the top end rebuilt and I would have to pay somebody to do that. After reading today that someone has had more than one NOS cam chain stopper lose its rubber I have lost heart. I can't pay somebody to tear the engine down more than once. It would be a huge waste of money. Maybe I need a new bike that doesn't need constant fixing. It's already a shame that I just paid somebody to relace the wheels because it probably didn't add anything to the resale value.

 

[happydaze]

Thanks @XSLeo. I'll try to get the piston out and clean it. I think I have to sell this bike.

 

[Brassneck]

Sorry to hear it, but you're not the first to feel that way.

These bikes are a lot of little things to have to keep up on and constantly address. Very hands-on--especially compared to anything built in the last 10-15yrs. And sometimes it is just not right for some, or the way I like to think about it, it's not right for some "right now"....ten yrs later, who know? With more time/money and perhaps a modern bike to ride while you wrench...these concerns simply go away as priorities change.

I can say, however, having had one back in the early 90's ('78 standard) and selling it for various reasons, that I ALWAYS thought about that bike and wished so bad I never got rid of it. Fortunately, I found another a few years back and built the bike I had always wanted (but couldn't do so for lack of money/resources/knowledge).

Good luck!

 

[happydaze]

Thanks @Brassneck. Right now my big issue is that the top end of the engine needs to be rebuilt and I don't have the time or place to do it myself. After reading someone's post today about the rubber falling off of more than one NOS cam chain stopper, I'm totally disheartened. I can't hack that. I'd be better off buying a new bike.

So, I'm going to fix the brakes and then sell it. This bike was my brother's and he died, so I have tried to keep it going. I don't mind little jobs but if the engine rebuild goes wrong I'm going to wish I never saw it. If I sell it I will never buy another one.

 

[Brassneck]

I'm sorry to hear about your brother... that's rough, and good job trying to keep it going. Good luck with whatever you decide to do. There's no wrong answer.

 

[fredintoon]

Hi happydaze,
NEGATORY on the Easyouts! Their very name is a snare, a delusion and a black lie.
They either cam out to leave an ugly conical hole or they snap off in the fastener leaving a chunk of itself that's harder than any known drill bit.
Here's what I do with rogered-up crosspoints.
Put a hexagonal crosspoint screwdriver bit in your drill press chuck.
Unplug the drill press, this is a hand job.
Block up the master cylinder on the drill press work table so the cover is parallel to the ground.
Force the crosspoint bit down into the cratered out crosspoint head and hold it down hard with the drill feed handle.
Back the screw out by turning the drill chuck by hand.
The m/c's innards will pull out after you've removed the snap ring that holds it all in.
It's deep down in the hole, MikesXS sells the long reach snap ring pliers you'll need to reach it.

 

[marp68]

Sorry to hear about your brother.

Regarding the brakes, I too am rebuilding them. Not the same model though. But I agree that the M/C probably needs to be disassembled and cleaned out. But it's not that complicated as I first thought. I didn't even need a special grip to get the snap ring out. The washer under it may have rusted, but with a thin wooden rod you hit the piston from the other side and it will loose and the piston can then be removed. Then just wash it, check the small brake fluid holes, use some brake fluid to lubricate all parts and put it together.

When I once broke off a small bolt, I used a left driven drillbit and while drilling, rotating left turns, the bolt unscrewed and came out nice and easy. Just be sure that you use this special left driven drillbit.

 

[happydaze]

Hi @fredintoon. Nice to hear from you, but I don't own a drill press.

Thanks @marp68. I'm going to try to remove the piston from the one with the stripped screws first. If I can get it out without damaging anything I'll try the one I bought on ebay.

When you do the front brake, you really need to clean out everything. My mistake was rebuilding the caliper but not the master cylinder. I ended up with new crap in the caliper when the brake fluid started moving around.

At this point I just want to get the front brake to work so I can start trying to sell this bike. After reading yesterday about a guy having 2 cam chain stoppers fall apart, I have lost all desire to put any more time or money into this bike.

 

[XSLeo]

If you still have the stock rubber lines, check for a plastic ring around them somewhere. This ring has the date the line was made on it. If the line was made about the same time as the bike, then replace the lines.
Rubber brake lines rot from the inside as they age. This rot leaves tiny rubber particles in the brake fluid. These bits of rubber plug up the passages and holes in the M/C and caliper. Just flushing the lines will help but can't fix the rot.
New rubber lines or upgrade to the braided stainless lines is a good thing.
I understand your loss of a brother, I inherited a lot of stuff from my brother a few years ago. Some things I passed along to other family members, most I still have.
Rebuilding an engine doesn't take a lot of space. A 4 by 8 storage locker is snug but doable.
Tools you need are mostly simple hand tools. Tearing the engine down for a top end isn't hard to do. Many on here were afraid of doing this. One day they just decided to do come what may. They have successfully rebuilt their engines and are very pleased with the bike. They found that these engines are simple and easy to work on.
Just follow the steps in the repair manual on how to tear down and inspect the engine.
We can help with the tough spots.
When you come to things like measuring the pistons and cylinders for wear, most machine shops can do this for a small charge. If boring the cylinders is needed the same shops can do this. I had a cylinder bored for $35 per hole. Even check out the larger lawn mower repair shops, a lot of them do rebores.
Anyway, If you do sell I hope you find it a good home.
Leo

 

[happydaze]

Thanks Leo. I want to sell it. I'd like to spend my weekends riding, not wrenching. Time is too precious.

After hearing that the NOS cam stoppers fall apart, I have no desire to invest any time or money in this engine. Time for a newer bike. I'm looking at the HD Street 750. I can get a low mileage used one (2015) for $5k-$6k and it looks like a great bike for my needs.

 

[Brassneck]

My g/f's 2015 Subaru Legacy that she bought brand new, had the change lanes warning indicator go out repeatedly. The part had to be replaced 4 times...and then various error codes kept popping up over the 6 mos. She had it...she was at the dealer 28 times getting this and that addressed. They ended up calling it a lemon and replaced it with a new car...with NO problems to date.

My point is that there are always things, even on a new modern vehicle, that can have quality control issues...the nos cam chain guide isn't the best design, but its not that bad...who knows why they broke? maybe the eBay seller who sold them knew they were crap, or they were installed wrong, or a bad batch?

Anyways, best wishes.

 

[happydaze]

I recently asked a friend if he thought his Subaru was a good car. He said "Every time I fix one thing something else breaks."

Yes, who knows why those cam chain stoppers broke but since I have to pay someone to work on my bike, the idea of having parts fail on an expensive job is not a viable option for me.

I usually work 65-70 hours per week. On the weekends I don't want to be bogged down with self inflicted b.s. I need a bike that runs right and doesn't need expensive repairs.

 

[5twins]

Unless your vehicle has a warranty, any shop performed repairs will be expensive. I guess that's why most of us here do our own work. In fact, that's mostly what this site is all about. I think a new, or at least newer, bike is best for someone in your situation.

 

[weaselbeak]

A properly maintained XS650 is as reliable as a stone bridge. I'm not sure why people think they can buy something 35-40 years old for a few hundred bucks and do nothing but ride. The brand is irrelevant. It sounds like you should go buy something new and with a warranty. These older bikes that have been around for decades should be left for the enthusiasts who understand the deal and have either money or an ability to get them up to snuff again. Take a close look at any of the new bikes, and check out the complexity. What do you think those plumbing nightmares will be like in 35 years? If you want a reliable XS650, I'm sure you can locate and purchase one, possibly here on the forum, that has been properly refurbished to a like new condition. As to the master cylinder, unless you're into a 100% resto, why bother? Brand new on fleabay for under 30 bucks and they've always worked for me just fine.

 

[happydaze]

Thanks. I agree. That's why I want to sell it.