Modern Vespa

After following the brake fluid change thread here...

My ET4 is overdue and I'm planning, for the first time, to take care of it myself. If I don't have the time...I've been busier than hell the last month or so...I'll have the dealer do it next month when I have to bring it in for inspection anyway.

But I'd really like to learn to do it myself. And, as always when I'm treading where I haven't been before, I'm a bit nervous about it.

The only MV article I found was this one...

GTS Brake Fluid Flush

Which seems clear enough...

But I'm a "measure twice, cut once," type.
If anyone can point me to other articles or advice regarding the ET4 in particular that might be of additional value, I'd appreciate it.

Guess I better get myself to Harbor Freight.

I went with this kit from harbor freight. I opted for this one due to the long run to the rear brake on my Burgman. Not really an issue for you but it's always nice to be able to justify tool purchases.

The first couple of minutes of the video here show you how to remove the headset to get at the brake fluid reservoir.

Good luck

All you really need is a piece of plastic tubing that fits snugly over the bleeder valve and a little cup to dump the old fluid in. It's always a little easier if you can get someone to pump up the brake and hold it while you release the bleeder valve but many times, I've done them by myself on motorcycles and our Vespas.

Couple comments on the wiki:

1) kit not needed, clear plastic hose(pennies at your local hardware) that fits the nipple and a clear bottle will be fine.

2) fluid spill on paint is not catastrophic. Brake fluid does not eat paint like a solvent. Simply flush any spill with water.

3) before starting, drain the reservoir almost completely -- but not all the way(introduces air into the system.) Minimizes contamination of fresh fluid and makes the process go quicker.

4) siphon method works usually works fine as long as you don't let the reservoir empty. If you screw it up or it doesn't work there's always the pump-and-hold method.

Good luck. I'm sure it will go well. Let us know how it went.

Thanks for the info.

I might have a chance to do a little touring later this week, so I'll probably give the brakes a go after I get back.

I'll let you all know if anything explodes.

I have the brake fluid, I have the bottle, and soon, I'll have the time.

I found these one-way bleeder valves

http://www.cyclegear.com/spgm.cfm?L1=&L2=&L3=&L4=&item=MRX_BB1

that promise to make the job a little smoother. I was wondering if anyone had any experience with them, positive or not.

Another quick question: On Windbreaker's article, it shows the bottle positioned below the bleeder nipple. On the instructions, it says to place the bottle above the bleeder nipple. I've seen pics both ways. Does it really matter? (I mean, it's no big deal either way it's simple enough to move the bottle , but I'm curious.)

Possibly they want the bottle above to put some kind of pressure on the one-way-valve. (I'm reaching for a reason.)

Let us know how this kit works. I need to change mine too, and this looks like it can be one person job.

I bled my ET4 last weekend. After removing the headset the whole process took around 15 minutes. It was the first time I'd done it. Probably only take 10 minutes now that I "know what I'm doing".

I used a one man brake bleeder I got from Griot's Garage. Already had the air compressor. Worked like a charm.

Open brake fluid reservoir, connect hose of bleeder to nipple on caliper, connect ait hose to bleeder, loosen nut, pull trigger on bleeder, add DOT4 fluid to reservoir as you're bleeding, when brake fluid being pulled thru turns from dark (dirty) to light (clean new fluid) tighten nut, remove hose from nipple. replace cover on nipple, top off reservoir, replace reservoir cover, test brakes, install headset cover, done.

Took me longer to type this than to bleed the front brakes.

http://www.griotsgarage.com/product/tools/specialty+tools/one-person+brake+bleeder.do

I did mine when I got her. I used a syringe and sucked out most of the fluid in the reservoir first and then refilled with new fluid and sealed it back up. Then I put a hose on the bleed value and bled the hose out by gently pumping until the fluid coming out was the new, clearer fluid. Then I closed it off, opened the top reservoir up and topped it off and was done.

Easy to do by yourself.

Went through the process with my LX150. I assume that the process is similar for the ET4.

I wrote it up in this thread: Help with Brake Fluid

Good luck!

Fail

I did all my prep, used the one-way bleeder valve (I don't have an extra pair of hands to help) and...

When all was in place, I loosened the bleeder nipple, but when I pumped the brake handle nothing happens...I can barely squeeze any fluid through the hose and the level in the master cylinder barely drops. The one-way valve works, for what little amount I was able to get through it...

When I loosened the bleeder nipple a bit more, a very small amount of fluid will come up through the hose with continuous pumping, but fluid then leaks out around the bottom of the nipple, too.

I don't want to risk damaging anything with leaking fluid, or getting air sucked back up into the lines, so I closed everything up.

Any suggestions?

Did you take the fluid reservoir cover off first? Sounds like there was something keeping the fluid from draining. Think about how you can stick your finger over the top of a straw and pick it up out of the beverage without any leaking out - your brake fluid system is the same way with the lid on the reservoir.

Yes, I did. I'll outline my steps exactly to see if that helps out:

1) Installed the Stockton brake bleeder kit
http://www.cyclegear.com/spgm.cfm?L1=5007&L2=31&L3=7001&L4=&item=PRC_L35-640&name=STOCKTON_TOOL_COMPANY_Brake_Bleeder_Tool
on the nipple, making sure the arrow on the one-way valve pointed in the direction of flow.

2) I placed the free end in a clear bottle. I also used a small syringe to put a small amount of clean brake fluid in the small hose end that connects to the nipple to prevent any air from being drawn into the system.

3) I removed the reservoir cover, making sure everything was clean.

4) I loosened the bleeder nipple and, while watching the level in the reservoir, slowly starting pumping the handle.

The handle would move freely, but after repeated squeezing the level barely moved. When I looked at the hose, old fluid had moved in up to the one-way valve, but not very much.

I loosened the bleeder nipple a bit more and I was able to move a small amount of fluid into the hose past the one-way valve (so I figure that's working) and even a drip or two in the bottle, but I also noticed some fluid coming out around the bleeder valve, which I cleaned up. In any case, repeated squeezing of the handle had little effect.

If I backed off on the bleeder nipple, nothing much happened. If I loosened it a bit more, it would start bleeding out around the base.

At this point, I put everything back together and, as far as I can tell, the brake still works fine.

According to everything I've read, you just "loosen" the bleeder nipple...maybe up to 1/2 turn...the amount doesn't seem too critical. Am I doing something wrong there? I don't think I loosened it even that much before it started leaking.

Hmmm... Not sure exactly where you've gone wrong. When I've bled cars before with a helper, I've followed the following pattern over and over until bled:

(1 person sitting in car, me @ brake caliper)

open nipple on caliper, push brake pedal to floor, close nipple, release brake pedal to top, open nipple, push pedal to floor, close nipple, release pedal to top...

Over and over again until bled.

I had to use a small hose clamp to hold the plastic tubing onto the bleeder valve. You may want to try that and see if the leaks stop.

Alternatively, try bleeding the system without the kit. I've listed the parts I needed in my post above.

I replaced the pressure clip on the bleeder nipple with a jubilee clip just in case it was leaking from around the hose. Same result.

I also tried the good old bottle method...loosen the nipple, squeeze the lever, tighten the nipple, repeat...same result.

Either method:
On the first squeeze, I'll get some fluid in the tube. One the second, third, whatever squeeze, nothing.

I loosen the nipple just a bit, nothing. Just a bit more, it leaks. I've already had to clean up fluid from around the calipers several times.

I'm stumped.

I want to make sure we are talking about the same thing. Are you referring to squeezing the brake lever? When I changed my fluid, I would slowly squeeze the brake once. Before releasing it, I then closed the bleeder valve. Added fluid to the reservoir and pumped brake to build up pressure again.

I never pumped the brakes with the bleeder valve open. Could that be the problem?

Thanks for the help. I think I had misread/misunderstood some of the instructions I read...compounded by the fact the instructions for using one-way bleeder valve were a fail and I was confusing the two methods...even though the valve itself worked just fine.

In any case, after a long time of doing this:
Pump the brake lever
Open the nipple and press the lever
Close the nipple
Keep pumping the lever until I got pressure again
Repeat

I was able to do the job. It took a while, a lot longer that I thought, but I have clear fluid throughout the system now.

I have to get off to work now, so I'll put the grip lock on overnight to keep the brake lever depressed (it feels fine, though) and give it a run tomorrow.

I'll report back then.

Thanks.

glad you got it done. did you end up using the one way valve, or just drain it into a bottle?

I'm back from work....looong day... Actually...both.
The instructions for bleeding with the one-way valve were a big fail. I still don't know why.

Since I already had the kit with the one-way valve in place, I just kept it on while I proceeded with the "traditional" method. At first I had problems with that too, because I didn't understand that I had to pump the brake lever several times to build up pressure before I loosened the nipple.

Because I left the one-way valve on, I didn't have to worry about drawing air back into the system, and I also didn't have to concern myself with keeping the bottom of the hose in the bottom of the bottle bathing in brake fluid for the same reason. I didn't have to worry about where to place the bottle either.

I'll probably do it the same way the next time...a year from now.

The fellow at the motorcycle shop said he installed speed bleeders on his bike, but I don't really understand how they work...maybe someone can explain it here.

That sounds right to me. I remember the process being longer than expected as well. Glad to learn that you got it working!

I did my first brake job on my 2003 ET4 150 scooter. It was an ongoing disaster but it's done, I learned a lot. I took both sides of the caliper apart because the brake pads sunk down into the dark zone and I couldn't get the pin through, I couldn't get the pistons to compress, so I let out the brake fluid, so now it's full of air.

There is a very teeny tiny o ring in between the two calipers, well, the first few tries, brake fluid was everywhere, including the brake pads. My Dad told me to use brake part cleaner, but numerous warnings tell me to replace the pads if contaminated, but I will do more research on that issue, long, long story short, that little o ring is really important, and the air bleeding process, I read about on this site was most helpful, no air, and good front brakes!

My daughter and two grandkids moved in with us, so saving money on scooter repairs is really helpful! I hate mechanical stuff, if you do too, just stick it out, read this site and you'll get it too!

Just to add insult to injury, brake bleeding is an inexact science with one way valves. Once a nipple is open, air can actually be drawn into the circuit via the threads of a loosened bleed nipple.

The only way of bleeding correctly is to open the nipple as soon as pressure has been applied at the lever, and to close it before the lever has come to the end of its stroke. Not easy, but once you've got the rhythm, possible. If the bleed nipple is open when you are releasing the lever, you are 100% likely to draw some unwelcome air into the circuit.

That's why a two person bleed is recommended if you don't have a pressure or vacuum bleeding kit. So much easier.

+1!

I don't see how a rear brake bleed could be done without two people, or a kit. At least with the front one can tighten the bleed valve while holding the brake lever at the same time.

Call me Mr Controversial, but I quite like having a nice spongy front brake. Rock hard brakes are all well and good on a car, but the progressive feel of the brake on my et4 makes it much easier to control and avoid locking up the front wheel, especially in the wet. As long as you can't pull the lever all the way to the grip then it's fine.