Brakes

[jeffro1954]

This is probably an obvious question but I'll ask anyway since I'm not much of a mechanic. I assume the master cylinder slide (for lack of the correct term) should return almost immediately when the hand lever is let go? Bike has been sitting for 6 years and I'm guessing like the rest of the braking system the master cylinder needs to be rebuilt. My second part of this question, rather than buy a kit to rebuild a 32 year old master cylinder perhaps I should just go out and buy a new master to replace the old one? I have heard rebuilding is not always that successful.

[mxmikie]

my master did the same thing after sitting for 10 years a little wd-40 on the shaft fixed it .....2 years ago

[trbig]

Take it apart and clean the O-ring and see. Wouldn't hurt to take the piston out of the caliper and clean it and that O-ring up also. Sometimes that rubber can get a gummy surface and just needs to be cleaned. Replace all that old fluid, clean the "Spooge" hole, and try it before possibly wasting your money on new stuff.

Also, I wouldn't use ANYTHING on brake parts to clean them except new brake fuid or brake cleaner.


Tod

[XS1100 Newbie]

TRBIG is right. The cleaning, and changing of the fluid is the first thing you should do. It also allows you to see what shape the bore is in.

[CatatonicBug]

Just remember that there are 3 essential parts to the brake system: The master cylinder, the hose, and the caliper(s). ALL of these parts need to be flushed and cleaned regularly. If it's been decades since the last time it was done (or you don't know when it was last done), do yourself a favor and take the entire system apart, down to the individual components, and clean them REALLY WELL. The parts that may need to be replaced are the rubber ones (piston seals in the master cylinder and the caliper).

Remember when you take the piston out of the caliper to remove the rubber seal, and clean UNDER the rubber o-ring. That groove collects junk and can prevent the piston from moving properly. A dental pick or other small pointy metal object works well for that job.

As for your original question, yes, the piston should rebound IMMEDIATELY after releasing the brake lever/pedal. This allows you to constantly adjust the pressure that you apply to the brakes.

[jeffro1954]

Did take the caliper apart as you mentioned cleaned it in denatured alcohol and replaced the o-ring and dust cover. piston had some pitting, but hopefully minor enough that it won't affect performance too much. I know what you mean on the rubber sticking, the self adjusting part of the caliper was stuck so cleaned that, still doesn't seem to slide all that well.
Must be interesting getting that snap ring out? So far haven't spotted the two little holes to get a tool on it.

[CatatonicBug]

Must be interesting getting that snap ring out? So far haven't spotted the two little holes to get a tool on it.

They SHOULD be there... Unless the snap ring is broken. Once you get the MC apart, concentrate on the Spooge hole. Use a small piece of wire to ream out any gunk that might be stuck in there. A search for Spooge hole will give you plenty of results for details on where it is if you have difficulty finding it.

[fredintoon]

Did take the caliper apart as you mentioned cleaned it in denatured alcohol and replaced the o-ring and dust cover. piston had some pitting, but hopefully minor enough that it won't affect performance too much. I know what you mean on the rubber sticking, the self adjusting part of the caliper was stuck so cleaned that, still doesn't seem to slide all that well.
Must be interesting getting that snap ring out? So far haven't spotted the two little holes to get a tool on it.

Hi Jeffro,
um, it's the master cylinder, the lever-thing on the handlebar?
Or the caliper, there's two of them, they each grip one of the brake disks?
To get at the master cylinder's innards you need a long reach snap ring tool.
MikesXS sells one for $10
http://www.mikesxs.net/products-7.html?category_id=7.1
Scroll down to the bottom of the page to see it, item #35-0009.

[Yard Dogg]

Here's how I clean small cylinders. Take em apart, wrap "fine grade" steel wool around a drill bit, soak it in brake fluid and spin it until the gunk is gone. Don't try to actually hone with it. But it will get the cylinder clean.

[psycoreefer]

Hi Jeffro,
um, it's the master cylinder, the lever-thing on the handlebar?
Or the caliper, there's two of them, they each grip one of the brake disks?
To get at the master cylinder's innards you need a long reach snap ring tool.
MikesXS sells one for $10
http://www.mikesxs.net/products-7.html?category_id=7.1
Scroll down to the bottom of the page to see it, item #35-0009.

You don't need a long reach set of snap ring pliers, it might be easier though. I just did my master last night, all you have to do is hold the cylinder in with one hand while you grab the snap ring with the pliers in the other hand. Worked just fine for me....

Also cleaning that groove behind the caliper seals is real easy if you use a dremel with a baby brass wire brush on it, the brass is hard enough to blow all the crud out and get it nice and clean but not hard enough to hurt the metal of the piston.

[jeffro1954]

It's been interesting trying to get this bike back into shape, a 1978 XS1100. Sat in a a guys barn for 6 years. He said if I could start it, he'll take $100. If I can't start it don't bring it back. The carbs were so varnished up, I found another set. Started up almost right away, although still needs synching etc., compression is excellent. Changing over Yamaha fairing back to regular headlight etc. By the time I get done with replacing and rebuilding I'll have enough into it I might have found one that already runs!! But I wouldn't trade the fun of working on it. This website has proven invaluable for a novice. Appreciate eveyone's helpful comments. You all rock!

[Yard Dogg]

It's been interesting trying to get this bike back into shape, a 1978 XS1100. Sat in a a guys barn for 6 years. He said if I could start it, he'll take $100. If I can't start it don't bring it back. The carbs were so varnished up, I found another set. Started up almost right away, although still needs synching etc., compression is excellent. Changing over Yamaha fairing back to regular headlight etc. By the time I get done with replacing and rebuilding I'll have enough into it I might have found one that already runs!! But I wouldn't trade the fun of working on it. This website has proven invaluable for a novice. Appreciate eveyone's helpful comments. You all rock!

You're not alone. There's lots of us monkeys in here swinging from the trees working on our PO neglected bikes. I thought mine was gonna work out better last year until I rode it a few thousand miles. Now things have loosened up and I'm starting to see what kind of shape it's really in. Just clean and lube the heck out of everything you can find. It will help in the long run.

Kind of makes me feel better to see new people getting on here after finding bikes like mine. I feel further along than I was. Keeps me motivated.

[crazy steve]

...I assume the master cylinder slide (for lack of the correct term) should return almost immediately when the hand lever is let go? Bike has been sitting for 6 years and I'm guessing like the rest of the braking system the master cylinder needs to be rebuilt. My second part of this question, rather than buy a kit to rebuild a 32 year old master cylinder perhaps I should just go out and buy a new master to replace the old one? I have heard rebuilding is not always that successful.

If the master piston still moves (even slowly), you can very probably save the cylinder, maybe even without a 'kit'. You can buy a new one, but it's not a duplicate of original so there can be a bit of 'adapting' involved.

I just got done rebuilding my brakes (have yet to install them). Everything was pretty much seized up, but the only parts I needed to replace were the caliper pistons as they were rustier than I liked. As far as the master cylinders (and if the front is bad, the rear is probably worse), as everybody says take them apart and thoroughly clean them. Yes, getting the front one apart is a large PITA, but after you get that snap-ring out the rest is fairly easy. The rebuild kits replace all the internal parts in the cylinders, so if the pistons and return springs are really corroded/rusty, I'd recommend you buy a kit. Keep in mind that brake fluid attracts and holds water, so any rust you find inside on any part must be completely cleaned off or it will be back.

Now, after you get everything apart and cleaned up (don't forget the 'spooge' hole on the front AND the rear has one too), see if the bare piston will slide easily into the bore. No? If there's no visible scratches, pits, or gouges, then hone the bore. Now, you won't find a hone small enough to fit, but a 6" length of 5/16" or 3/8" wood dowl with a slot cut in one end with a folded piece of 1000 grit sandpaper (or finer) will make a good 'flapper wheel' hone. Carefully and lightly hone the bore until the piston does just slide into the bore. Clean everything up and reassemble and it's fixed. The cylinder bodies, being aluminum, don't pit badly like a steel/iron one would.

A few last tips; on your caliper slides, get some silicon-based 'high temp' grease. The stuff I have (Atlas brand; unfortunately bought about 35 years ago at a Standard Station so you won't find this brand anymore) is safe for rubber and won't wash away. Just a dab will do ya and it will make a big difference. And clean the snap-ring groove on the front cylinder while you have it apart with a pick or a sharpened bit of wire, as that will make getting the ring back in easier.

'78E original owner

[XS1100 Newbie]

Jeffro
You say you are removing the Yamaha fairing. What are you going to do with it, and is it in fair shape. Does it have the Yamaha name on it?
Bob

[jeffro1954]

It's in very average condition. lights worked. there are some cracks. Don't remember if the Yamaha is still on, but I believe they are. I can take some pics and send them to your email. Not quite decided if I would ever put it back on, right now I doubt it. It's in storage, will take a few days to get pictures to you.