Front Brake Master Cylinder Leaking

[JProdun]

Hey all,

This morning I noticed that my front master cylinder is leaking all around the cap edges. After a ride to work, the fluid seems to stay at a min level indicated. What should I do to fix this? Is there a gasket that could be replaced? Should I add a little fluid before the fix comes through (if yes, what type of fluid please)? Really don't feel like taking it to a dealer... Don't have the time to deal with this.

On a second note, always wanted to ask if anyone has replaced it with an aftermarket and how difficult of a process is it?

Thank you all!

Oh, btw, mine is a '14 V7.

[CapitalGoose]

I am actually experiencing the same problem ('16 V7II). I believe conventional wisdom says to remove the cover (after having cleaned the reservoir thoroughly), clean the inside of the cover and gasket, dry both, refill the reservoir, and recap. I think there are gaskets out there (Maybe try the folks at AF1Racing) if this doesn't solve the issue.

I haven't tried any of this yet, but this topic has been covered in earlier posts. I ordered some DOT 4 brake fluid (Belray super DOT4) to add in case the reservoir is low. I rode to work today and I'll check/clean/replace, etc once the brake fluid comes in.

I'm going to try the cleaning first before I consider trying to find the part or replacing the whole cylinder.

I'll keep you posted and I ask that you do the same for me whatever you decide upon!

[Trogladyte]

Do you mean the cap on top of the reservoir?

[CapitalGoose]

Oh yeah,

I've read that if you have a screen on the bike (I do), the vacuum/vortex created behind (in front?) of the reservoir may be enough to suck a small amount of fluid out.

Again, I'll let you know once I've cleaned and refitted everything.

[Trogladyte]

Oh yeah,

I've read that if you have a screen on the bike (I do), the vacuum/vortex created behind (in front?) of the reservoir may be enough to suck a small amount of fluid out.

Again, I'll let you know once I've cleaned and refitted everything.

Really?

That sounds most unlikely. I have a screen and I don't get leaks.

Have you had the top off lately? Have you tried just tightening up the screws? If that doesn't work,then just clean carefully and refit.

[JProdun]

Thank you all!

I'll clean and refit and tighten and see what happens. Lot's of "ands"...

Don't have the screen, but do believe all the vibrations and road conditions in NYC could've caused it to loosen up.

Thanks again!

PS: I'd get something like this or similar, but assuming brake bleeding is involved?
http://af1racing.com/store/Scripts/prodView.asp?idproduct=56039
http://af1racing.com/store/Scripts/prodView.asp?idproduct=76513

[CapitalGoose]

Really?

That sounds most unlikely. I have a screen and I don't get leaks.

Have you had the top off lately? Have you tried just tightening up the screws? If that doesn't work,then just clean carefully and refit.

Yeah that's what I thought too. My screen isn't terribly large and MAYBE this is a possibility. I don't know. I'll clean everything and refit this evening and get back to y'all.

[Old Jock]

I must admit that's a new one on me, I've got fairings on my 2 scoots and no reservoir leaks

Regarding installing an aftermarket reservoir, it can be done without the requirement to bleed the system, but I'd drain it all down anyway as it would reduce the chance of getting corosive brake fluid all over the bike and possibly damaging the paint.

I  don't know the V7 but brake bleeding is not rocket science and can usually be done reasonably easily with some tubing and a glass jar, if its a bit harder a syringe or 2 syringes may be required but that's about it

Regarding the Rizoma reservoir they make a really nice one now with a big window Droooooool



John

[Mike Tashjian]

Reservoir caps are suppose to have an air inlet. The rubber layer underneath is usually formed with folds that will let it deform as fluid is pushed down into the hydraulic system as brake pads wear. Sometimes there is a plastic form to help stabilize the rubber.  If you have a leak remove the cover, clean all the parts, refold the rubber layer and replace the fluid in at least the reservoir. The handle bars will have to positioned a certain way to fill the reservoir and be sure to clean any spills immediately  with plenty of soapy water and rinse thoroughly.  If the screws became loose or the rubber moved it can lose its seal and it will leak. Air screens will not make them leak, ever. They are a sealed system.  The moisture from regular air will over time contaminate your brake fluid even when they are sealed.  Bleeding on a regular basis should be part of your maintenance schedule.  Mike

[pazzmore]

ug... me too. only 2600 miles on it.

[sib]

This is a known issue with the V7II series.  There's a thread that discusses this problem, along with a couple others, over at Guzzitech:  http://www.guzzitech.com/forums/threads/new-v7-ii-stone-new-to-the-forum-new-bike-new-leak.16284/#post-122324

Basically, the two-piece (rubber dam and metal cap, no inner plastic cap) reservoir caps (2B001928) supplied with these models don't do the job, so when you bring your bike in to your dealer on warranty, MG will supply the previous three-piece (rubber dam, inner plastic cap, and outer metal cap) version (GU03661145), which has remained leak free over 13,500+ miles on my Stone.  If you'd rather not bring your bike to the dealer for warranty coverage, the GU03661145 kit can be purchased from, e.g., AF1 Racing, for about $50.

[pazzmore]

Thank you Sib. 6-8 week backorder from AF1. My local dealer retired.. closest dealer is now in Phoenix (100 miles away).    makes warranty claims a real pain in the a$$

[Stevex]

Just be careful that brake fluid doesn't blow onto your tank and take some paint off.

[pazzmore]

Found the part in stock at Harper's. $45 bucks.


Master Cyl. Lid & Gasket (#03661145)
Code: 03661145

[jpv7]

Every single v7ii I've see leaks at this location. Warranty it if not too inconvenient - $45 should be on Guzzi.  Stock cover is garbage.  We can thank the accountants, I guess.

[JProdun]

Have listened to advice here. Unscrewed, cleaned and put back together. Problem solved.

Thanks

[sib]

Have listened to advice here. Unscrewed, cleaned and put back together. Problem solved.

Thanks

....For now.  I hope it worked for you, I thought it did for me, and then a week or so later it started again.  For me (and my '16 Stone), the permanent fix was to get a warranty replacement with the older 3-piece cap assembly, like my '13 Stone had.  You mentioned in your OP that you have a '14 V7.  I don't know whether that year's V7's had the 3-piece or 2-piece reservoir cap.  If it's the 3-piece, then you very well may have had a simple dirt or looseness problem that you fixed.  If it has the 2-piece cap, then I'll predict that it will start leaking again, soon.

[pazzmore]

replaced the stock two piece cap with the three piece part. a week and several hundred miles later: no leaks.