Modern Vespa

you will need to have the resv. cap off to add fluid. when squeezing to bleed the line do it slowly and evenly. put slight pressure on the lever then open bleed valve while suqeezing shut the valve before the lever is fully back to the bars. You'll have to do this probably a good 10 times to ensure you get out any bubbles.

Don't mix types of brake fluid. If your has dot 3 use dot 3.

Can I leave the cap on while bleeding, and then remove it to replenish?
Again to avoid any spit-back or leaking.

(I'll add the same type of fluid thats engraved on the cap, DOT 3 or 4 whichever it says)

[quote="mattgordon"][quote="NightWing"][quote="mattgordon"][quote="NightWing"] Just a personal observation -- I had a very similar squealing on my GTS 250 (07) and bought a set of Egli pads for the rear. Stopped squaling for about a month and then started again...
I am following this thread with interest as I agree with you it is VERY annoying....

you could but you'll end up taking it off and putting it back on alot as the resevoir is not that much and you don't want to bleed out all the fluid in it. just go slow and easy don't jerk the lever and you will do fine. Ifyou want wrap a towel around the base of the resevior just in case .

I am delighted, nee 'giddy" to report that my brake squeal has been resolved.

My hunch regarding the different types of pads was not the solution, however I'm well versed at the brake-pad change technique now. Always a silver lining

I attempted the overnight brake-lever pressure technique which did not work, although the lever had a better, crisper "feel" to it afterwards, then before.

I purchased a Lisle Brake Bleeder model 19200 at Sears' tool department (Fantasyland as I like to call it...) for just $6.99, and fully bled the rear brake circuit with it. The old fluid was a greenish yellow, and thicker in consistency than the new, and we bled it until the fresh DOT 4 material appeared in the little bottle. As was mentioned, I did have to add to the reservoir numerous times during the process.

Did this all in a few minutes, with the rear wheel on, and the brake works and feels better than it has in thousands of miles, and is quiet, squeal free and effective even at low speeds and light lever pressure.

Just out of preventative principle alone, I will likely flush the fluid from all of my bikes brake systems from time to time, as I've seen the difference between old and new brake fluid now. I believe it's a scheduled maintenance item anyway.

Anyway, it's easier to do than I anticipated, the hardest part was protecting from any fluid spills or drips, and disposing of the spent fluid...if you are suffering with screachy brakes, this may be the cure for you.

Good work Matt, but why does the brake fluid cause the squealing? My rear brake only started to squeal since I had new pads put on it after the original set was soaked with oil. The bike only has 2900 kms on it at the moment so I cannot imagine that it is a problem with the brake fluid, but it seems to have solved your brake problem.

My Fuoco front brakes have started to 'squeal' a tiny bit over the cold weather - and it is noticable that the first front brake lever squeeze of the day goes in a bit further than normal (just the once though).

Brake fluid is 18 months old (last steering bearing change), though the pads have been changed since IIRC. Fluid level fine.

I absolutely bet new fluid *and a clean of the retaining pins* would cure - and a smear of new copper grease wouldn't hurt.

great job. isn't it amazing how that old fluid looked. You should only need to do this every other year. Now think about that 4 wheeler your driving around.....hmmm.

That's not to say your brakes don' t have air in the line...that's the primary reason to bleed them, and indeed I had air in my old fluid. The air bubbles make it difficult to apply full and proper pressure and that can contribute to squealing. I don't believe air is related to the age or mileage of the scooter. Just one of those thing that can happen.

OAD-It certainly was enlightening and I have a new outlook regarding brake fluid as a regular maintenance item

Thanks for the advice...

When I bring my scooter in for it's second first service, I'll ask them about that. The funny thing with the rear brake squeal is that I get it every time I first get on the scooter after it has been sitting for a while. If it "ride" the rear brake it goes away only to return the next time I ride after the scooter sits. Do you think those symptoms fit with the diagnosis of air in the brake line?

Yes, because the brake system is cool after having been unused for awhile and the air can collect into one larger bubble, reducing the pressure when you apply the brakes, making it squeal. Once you start using the brakes and the brakes (including the fluid) heats up, the air bubble likely disperses into many smaller bubbles and the squeal is minimized or "eliminated". YMMV.

My squeal appeared after they installed new pads as well, perhaps by virtue of the fact that the caliper was being messed with some air may have crept in?

I just took an early (chilly, at least by Calif standards) morning ride after an overnight period of sitting and still no squeal....I officially declare my problem solved by bleeding the brakes.

I'm having trouble wrapping my head around the connection between air in the line and brake squeal. My understanding is that generally brake squeal is caused by vibration between the back of the pad and the caliper.

I suppose anything is possible, but the air bubble connection seems unsatisfying to me.

Put a chamfer (45 degree angle) on the leading edge of both inner and outer brake pad. The leading edge is the direction that the rotor turns towards.
This will eliminate any squeeling - works on your car also.

I believe it's between the back of the pad and the piston....why the pads come with the anti-squeal pad attached to the part that the piston pushes on. The metal-to-metal contact (pad plate to brake piston) is eliminated for that pad.

My contention is that the air in the line reduced the pressure the pistons placed on the pads and the pads in turn placed on the rotor, creating some type of point of vibration between the rotor and the friction surface. This was a high pitched howl...worst I've ever heard.

In my situation, every other component was eliminated; pads (X 2 sets), and rotor. The squeal persisted until the air/and or old fluid was eliminated from the equation. I assume the braking pressure is now more sufficient, consistent, or without compromise from an air bubble.

Time will tell.

Keep us updated. It's a curious problem.

I have always found brake squealing to be an interesting topic. It will be very interesting if this continues to be the solution for you Matt. Please keep us posted. I may have to ask my mechanic to have a look at that for me at my next service.

If brake fluid leaked out and dripped on your pads or rotor while you were bleeding then your brake squeel may return over time

The Lisle Brake bleeder contains all the fluid at the caliper end of things clean as a whistle....the bigger concern for me was spilling some fluid up top on the painted plasticware.

Since you just had it in for service, can't you really press your service guys to fix it, I wouldn't put up with that for a second. Sounds like a headache and a hassle!

Well, normally I would do just that, however my initial request was ignored in lieu of 1) new pads which started this whole thing, and 2) a new rotor which did not remedy the squeal which occured after #1. Besides, I'd already been back twice for some remedy.

That being said, sometimes it's less of a hassle (and more satisfying) to take the bull by the horns yourself. Since I have both the time and impetus to do so, and with the help of interested advisors here on MV, feel the problem is resolved and hopefully others may refer to my experience if they have a similar problem.

At the very least, I'm convinced a bi-annual brake flush is a good maintnenance "best-practice" and something I'll perform myself (since the dealer apparently does NOT like to do them!) from now on.

Ahh understood. MV is the most awesome collaboration on the web for us Vespa owners

thats why they make brake cleaner. Available at auto parts store and most big chain places like wallyworld. stuff cleans the rotors and pads. recommend spraying heavy after serviceing brake areas.

After having my eyes opened to the benefits of routine brake fluid flush and replenishment, I attacked the front brake on my formerly troublesome GTS, and both front and rear brakes on Patty's GT200L.

We have 5 bikes in our collection that use this same reservoir, so I procured a cap from a wrecked scooter, and monkeyed this device up to help ease and speed fluid service in the future, and most importantly to minimize the chance of a brake fluid spill.

Feels good to know I have fresh, clean brake fluid in our Vespas....if the rain around here ever lets up I may even get out and take a ride!

Will flush the brakes every 2 years from here on out.

+1 on brake fluid changes.

For scoots the time and expense to DIY is minimal.

If you've got the kit, do your 4 wheelers too. Any time I get a new second-hand vehicle I'll do a BFC. Sometimes the blackness emerging is frightening!

Geez

Jess I'm guessing that instead of a nice solid column of brake fluid pushing against the pad, you have a bubble of air also. Depending on the pressure that bubble will compress. It would act like a spring allowing the pads to vibrate. I know one thing, as careful as I was changing brake pads I got air in the line. Not a lot but some. Then the first time I tried to use a one man bleeder I must have sucked air in somehow cause it got much worse. I ended up using a vacuum type from harbor freight and it works petty well.
No brake squeal

I laid my GT200 up for a valve adjustment and decided to address an annoying brake squeal I thought I was getting from the rear.

Upon closer observation, the squealing was coming from the front caliper, not the rear. I replaced the pads and saw that one was much more worn than the other.

With the caliper back on the axle, I noticed the scooter was much more sluggish. Raised the front end and as it turns out, the front caliper was sticking.

Not saying yours is, but its definitely worth checking and you won't notice it until you replace the pads. Serves me right for putting off changing the brake fluid.