Leaky clutch master cylinder

[kvb34441]

My clutch master started leaking recently. I'm not sure where it's coming from, as it only starts leaking when I'm riding. I've cleaned everything on and around the cylinder itself, and I just can't tell where its coming from. Is there a better way to find the leak? Or should I just get a whole new master cylinder unit?

 

[Fire-medic]

What year is it?

It's probably the rear seal, the one closest-to the lever. The "I've got no $" fix is a rebuild kit, available from Yamaha, or an aftermarket kit from someone like K&L, either online or possibly the local bike shop, probably needing to be ordered.

A question: is it leaking off the end of the clutch lever? Dripping off the ball on the lever end? That would indicate the above.

The leak can be an internal one, no loss of fluid, which apparently is not your case, this would mean that the clutch wouldn't work very-well if at-all. It shows as a lack of tension as the lever comes-back to the lever without resistance, or it comes-back almost-to the lever before any resistance is felt. In other words, the clutch won't disengage. Since you apparently are riding the bike, this isn't it.

My opinion, I buy a new clutch master cylinder. A rebuild kit may-not fix your problem if you have a worn cylinder. Then you're out the cost of the rebuild kit, and you still need to buy a new master cylinder. Like Clint says in 'Dirty Harry,' "do ya feel lucky?" (I left out the 'punk.')

As far as I'm aware 1985-2007, front brake and clutch master cylinders, all the same, all-years. Of course you need a clutch master cylinder for the clutch, and a front brake master cylinder for the front brake.

Sean Morley [email protected] probably has all these parts in-stock, and if you buy from him, you can get his assistance in any questions you may-have, or if something isn't going right, he can coach you through it.

Ron Ayres Yamaha: $141 for the new master cylinder. Part #1 in this fiche.
2006 Yamaha V-MAX 1200 (VMX12V) Front Master Cylinder 2 | Ron Ayers

Master Cylinder Sub Assy

2KW-W2645-00-00

Retail Price: $176.99

Your Price: $140.36

A rebuild kit OEM Yamaha is $31 (above link) so a considerable savings. Part #2, the same fiche.

Cylinder Kit, Master (Clutch)

2KW-W0099-00-00

Retail Price: $39.99

Your Price: $30.94

Buy four copper flat washers for the hydraulic hose:

Washer, Plate

90201-10118-00

Retail Price: $3.05

Your Price: $2.15

You only-need two, but, they're inexpensive, and it's a good practice to replace them when you remove the hose from the master cylinder. Same flat washers fit the brake master cylinder and the brake hoses, and the brake splitter, and the calipers. Have you ever dropped a nut/bolt, and had it successfully hide from you, never to-be seen again? That's why you buy four.

You can keep the old flat copper washers, and check them for flatness, it's not-uncommon for the washer to distort a bit from the hose fitting. You can lightly-sand the distortion off, and anneal them for a few seconds with a propane torch, and stick 'em in your spares drawer, be sure to label them so you know what they are. However, I suggest using new pieces.

About the only thing you need if you don't have one, is a l-o-n-g nose pair of internal-expanding snap-ring pliers. I've actually used a strong and long straight pick to remove the snap-ring, you only have to get one end unseated, and then you can work the ring off like a can-opener, to remove it from the groove. However, if you have a pair of snap-ring pliers, unless the steel snap-ring is horribly-corroded, they make the job easier. Make sure that the nose of the snap-ring plier is long-enough to reach the ring, and that the nubs on the tips are small-enough to fit the holes on the ends of the snap-ring. A too-short nose, or a too-big pair of nubs, and the pliers are useless.

If you're going the rebuild route, I use a piece of 180 or 220 wet-or-dry sandpaper. I wrap it around the end of a 3/8" long socket extension so that the coiled sandpaper is a snug fit in the master cylinder bore. Using a cordless drill, I have an adapter to fit the 3/8" socket, for the drill, Harbor Freight sells a set of 1/4", 3/8", & 1/2" adapters for probably $5. About 30 seconds is all you need to ream the bore. Us a solvent to clean it well, then use a bit of DOT #4 brake fluid in the bore, and slip-in your new piston assembly. Make sure that the snap-ring is well-seated. I usually use a 1/4" socket set to use a deep socket to fit the cylinder bore, and to evenly push-in the snap-ring, to seat it, you can usually feel/hear it 'click' into-place. However, you can also just use a long screwdriver, just make sure that the snap-ring is fully-expanded into the groove, when you push-in the snap-ring, and it hits the groove. Take a good look at the size of the snap-ring before you insert it, and you will know when it properly-fits the bore groove.

Fill the reservoir, bleed the system, and you're good to-go.

Notes on what works for me:

I usually remove from the handlebar, the master cylinder if I'm attempting a rebuild. I use a bench vise to hold it to use the snap-ring pliers. That way I can control the possible brake fluid spillage onto bodywork, you do-know DOT #3 and DOT #4 is corrosive to your paint, yes? I use a bulb syringe or a regular syringe, or a Mityvac to empty the master cylinder before I begin working. Loosening the banjo bolt, the bolt holding the clutch hydraulic hose, will also present a possible brake fluid spill ruining your paint job. Also, watch for brake fluid dripping-from the hose once you disassemble things. I find a roll of baling wire is great for tying-up hoses, to stop them from leaking everywhere, make sure the end is above the handlebar. Save the coathangers!

I keep a full can of WD-40 or CRC 5-56 and a big roll of paper towels to quickly remove by dilution and mopping-up, any spilled brake fluid.

A word about bleeding:
I find doing a reverse-bleed is the easiest, quickest way to successfully-bleed a clutch master cylinder or a brake master cylinder. Here's a link about it if you are unfamiliar with it, including how-to make your own syringe tool to do it, using a grocery store 'flavor-injector' and several pieces from your local auto parts store, and/or the hardware store.

Clutch slave cylinder replacement | Yamaha Star V-Max VMAX Motorcycle Discussion Forum (vmaxforum.net)

I fill the side of the clutch master cylinder where the hydraulic hose attaches, and then the washers and the hose, before I install the clutch master cylinder to the handlebar. If you're doing the reverse-bleed you do not need to fill the clutch master cylinder reservoir. This is an excellent time to drain the entire line and to replace the fluid. Because there is a supply of brake fluid in the clutch slave cylinder which you won't be able to remove unless you remove the slave cylinder itself, to invert it so all the brake fluid can drain-out, leaving the slave cylinder in-place will not entirely-empty the system of old fluid. If you want to do that, you need to order one of the engine gaskets for where the access to the slave cylinder is, part #19:

2006 Yamaha V-MAX 1200 (VMX12V) Crankcase Cover 1 | Ron Ayers

Gasket, Crankcase Cover 2

3JP-15461-01-00

Retail Price: $6.49

Your Price: $3.64

Since you're doing the master cylinder, make one mess, and be done with it. You don't have-to do this if you don't want-to, unless what you get out of the clutch slave cylinder is molasses-like and then the slave cylinder should be purged of nasty old fluid.

The clutch slave cylinder replacement is described in the link. This is another case of, "should I try a rebuild of the slave cylinder, or should I buy a new one?"

Part #27:
Push Lever Complete

1FK-16381-11-00

Retail Price: $126.99

Your Price: $99.25

Part #29:
Push Lever Seal Kit

26H-W0098-00-00

Retail Price: $36.99

Your Price: $26.64

That covers it, ask questions if you have any.

 

[user 16790]

I've had one leak from the 'viewing window'

 

[desert_max]

That covers it, ask questions if you have any.

Yowza! With the level of detail in that response, my Mother could do it!

 

[Fire-medic]

I've had one leak from the 'viewing window'

Got a dime? JB Weld it in-place of the cracked window.

Visit your friendly jewelry store, the old-fashioned one, where they do watch repair. Buy a sapphire watch crystal from them. Something about 18mm should fit. Same JB Weld treatment. You can find vendors on ebay for any-of this stuff, but visiting your local jeweler is what I've done. Bring your cleaned-up master cylinder with you to match crystal size to the master cylinder opening. This is a good place to use some brass brushes shaped like discs and a Dremel-type tool to clean things up. Harbor Freight has the Dremel-type tool, I would get the slightly more-expensive one instead of the cheapo. They also sell the crimped-wire disc-shaped brass brushes inexpensively.

When you try to remove the old, broken window, try to preserve the bezel that sits in the aluminum casting. There's the one beneath the window plastic, then the window, then the trim bezel. Pretty-sure that's the order of disassembly/assembly.

 

[02GF74]

Dust the master cylinder with talc and it will get washed away by any leaking fluid.... but some, maybr most of it may get blown away when riding.

 

[kvb34441]

Everybody is so mf helpful in the forum it's amazing. thanks a lot!

 

[user 16790]

Got a dime? JB Weld it in-place of the cracked window.

Visit your friendly jewelry store, the old-fashioned one, where they do watch repair. Buy a sapphire watch crystal from them. Something about 18mm should fit. Same JB Weld treatment. You can find vendors on ebay for any-of this stuff, but visiting your local jeweler is what I've done. Bring your cleaned-up master cylinder with you to match crystal size to the master cylinder opening. This is a good place to use some brass brushes shaped like discs and a Dremel-type tool to clean things up. Harbor Freight has the Dremel-type tool, I would get the slightly more-expensive one instead of the cheapo. They also sell the crimped-wire disc-shaped brass brushes inexpensively.

When you try to remove the old, broken window, try to preserve the bezel that sits in the aluminum casting. There's the one beneath the window plastic, then the window, then the trim bezel. Pretty-sure that's the order of disassembly/assembly.

it was/is leaking from the seal of the window, I do have a dremel but I've also replaced the master cylinder with an XJR item

 

[MaxMidnight]

Lots of info here

 

[Radioguylogs]

I had a leak in the brake MC that occurred only after braking.

I was surprised to eventually figure it it was the cover (lid).

 

[Fire-medic]

I had a leak in the brake MC that occurred only after braking.

I was surprised to eventually figure it it was the cover (lid).

Was it a cut in the rubber for the master cylinder cap? Because, the master cylinder needs a small vent to avoid an air-lock. Filling the master cylinder too-much could possibly cause a bit of seepage past this vent.

Back-when Superbikes were being ridden by Wayne Rainey, Freddie Spencer, Wes Cooley, and others, aboard the air-cooled 750cc inline-4's, it was a common practice to use a tennis sweat wristlet to-be stretched-over the master cylinder reservoir. That would absorb the heated brake fluid expelled-from the master cylinder due-to the over-taxed brakes' use. Pic is of a Freddie Spencer replica, faithfully re-creating that little re-purposed master cylinder sponge.

 

[desert_max]

I've never been a fan of the vent that FM illustrates above. It is a conduit to the outside world. They will weep on occasion - especially if overfilled. Mine did recently. I ignored it and wiped the weepage frequently. It stopped.

 

[Radioguylogs]

My cap was distorted by overtightened fasteners. I removed it, pushed it back into a straight shape, cleaned the area, and re-installed it. Finally my persistent leak went away.