Modern Vespa

Is there a trick on getting those 2 Allen bolts out of the front brake calliper. The one's acting as guides for the brake pads then self.
They are so stuck and badly sized that my Allen key is about to slip through leaving me with no way to change the pads.
Sprayed some penetrating oil on them and hoping the heat from breaking will help with that oil penetrating.
But other extra tips are welcome.

Just a thought but maybe you need something with a little more muscle that an allen key ... Use a wrench with 3in. extension and allan too give you a bit more torque. It may be the bolts were overtorqued when installed or just the allan key is not up too the job. Good luck and let us know how it turned out

I tried both, just a regular Allen key (good quality PB swiss tools) and a Allen bit onto a 1/2 wrench.
It's not the force that is missing its the key that is starting to loos it's grip inside the bolts.
If I apply more torque they will slip making the Allen pieces of the bolts rounded.
It's not the bolts that attach the caliper to the front fork assembly but the 2 little chromed bolts that are inside the caliper (Allen holes on the wheel side).
They are there to make the pads slide but stay in their place.

Hi Bommes

I tried everything, heat, penetrating oil, impact punch and all I managed to do was round out the bolt. In the end I bought a used caliper that had virtually new pads with the bolts free, then simply replaced the lot. Cost me £25 and had it changed and bled in less than half an hour.
Might be worth considering.

best regards Phil

They seize up - all calipers with the two allen bolts should have had the bolts removed, anti-seized and done up loosely again at PDI. Very common oversight, as when the pads do need changing maybe a couple of years down the road, they are well and truly corroded in.

If you are unlucky, a new caliper will be on the cards.

Take the caliper right off, heat up the caliper body and use a hand-held impact tool. The best outcome is the blots starting to undo - the worst is mashed-up heads needing a new caliper.

When you do have it all running again, ensure you check the bolts will move every so often - once every six months should do it.

I had a similar problem with allen bolts rounding off, and managed to remove them by hammering a tight fitting Torx bit into the damaged Allen head and using an impact screwdriver to loosen them. Good luck.

I had a feeling I would not have been the first with this problem.
The pads are still okay but I received some malossi sintered pads I wanted to install, but they have to wait a little now

Sprayed some extra penetrating oil in there again, got a weekend of riding around in the Dutch hills ahead so they will heat up just right.

Wow, I guess I lucked out! I got the Allen bolts out of both my front and rear calipers without any problem -- 5 years and 31k miles on the original pads.

Good luck!!!

I got them out
With the hot air gun, lots of penetrating oil, some strong language and a torxs bit that eventually slipped into the Allen head holes with a little pressure from the trusty old hammer.

Changed the pads for malossi sintered ones, and also replaced the ABS speed sensor.
To bad I still have no working abs.
This ABS system works with a combined brake system on the rear brake lever.
For the front brake it uses a electric pump wich amplifies the pressure deliver by the front brake lever.
That's were my gts has a failure, the pump does not work 8 out of 10 times. Resulting in minimum brake pressure, enough for riding solo but not enough for 2 up into the mountains.

New pump= 1000 euro...
Not a dealership that I know of who can identify the problem.
So I am kinda stuck without a clue..
Rip the abs out, replace the brake lines and convert the bike to a non ABS version??
Think that is my best guess.

1000? I'd rip them out and go non ABS. Reading this thread makes me not want ABS if i get another Vespa. Wow. Good luck.

I know for sure that the brake calipers are the same on a ABS and non ABS Vespa GTS.
So no replacing needed there.
The brake levers with their main pumps and reservoirs that I don't know..
Maybe the pressure is different between the 2 systems, so maybe the cylinder size on the brake levers are different between the 2 of them.??

Brake lines are easily changed and are not that expensive.
Ripping out the abs pump is strait forward, although there is a massive connector on it that is going strait into the main wire loom and just letting that connector hang loose.???

After some searching I found a second hand ABS pump with brake levers, calipers, brake lines the lot for 200 euro.
But for all I know the problem in my Vespa is in the wiring loom?? Or is some sensor I do not know the existence off..?
And who is to tell if that second hand system is working correctly..??

I'd take a chance on the second-hand unit - presumably out of a written-off Vespa. At the very least you get a 'new' front caliper - and from all the bits you can get some working brakes even if still without ABS.

Check the part numbers of the master cylinders between the ABS and non-ABS models - I'm sure a friendly dealer can help you there. They may well be the same - indeed I'd expect it.

If the master cylinders are the same, then it's just swapping out the brake lines and I have working brakes again.
(without talking/thinking about removing the not working ABS system)

The local dealership is very helpful, so they can look up the part numbers for the master cylinders for ABS and non ABS version. They can also supply original brake lines.

The second hand ABS system is definitely from a written-off (or stolen ) Vespa.
But I have a feeling I will end up with again some sort of error or failure after I spend 2 days swapping out the system.
Hell I cannot even find a "how to" on bleeding this ABS system, I know from the combined ABS system on BMW's bikes it's a biatch to get all the air out, do it wrong and the system is fooked..

Can your friendly dealer download and give you a copy of the ABS version workshop manual? If so you might email it to me as well so it can be uploaded to the 'manuals' webpages.

He gave me the only thing he could find and that was a systematic drawing of the brake system.
That's it..
Nothing more down that line.
He is very friendly in ordering parts, making good prices and so on.
But when it comes to motor scooters its just not really the works.

Over here your stuck between moped dealerships and motorbike dealers.
Both don't really have a clue what to do with our Vespa's.
A good electronics mechanic can find the problem even with out connecting the bike to the pc but there are non to be found over here in my region.

I found a online service manual for the ABS version of the 250 i.e.
To bad I need to register and pay to download it..
http://www.scribd.com/doc/128751519/Vespa-GTS-250-I-E-ABS-EN

Any way in there I found that the master cylinders have the same diameter on the abs version as on the non abs version.
So new part only need to be the brake lines.

Also in that manual I found some measurement checks I can perform to check some parts of the abs system.
To bad most of it need a tester unit from piaggio.
Even changing the brake fluid and bleeding it needs that tester, else you cannot bleed the main abs pump thing.

In other words if I can't find anything wrong with the simple measurement checks the system goes..

How about this for a triple post...

Problem sorted, even without asking I will tell you'll how.

when I bought the bike the abs pump was working even on a stand still.
On some occasions it failed all together and I was left with a minimum of brake pressure.

A few weeks ago the pump stopped running completely so no more extra brake pressure.
I went out and got my self a new front wheel speed sensor (was on order for like 3 months) and installed that.
What I was looking for was a rotating ABS pump with the bike just standing still.
That I didn't find so I went out searching for wiring diagrams, alternatives, new ABS systems and so on.

Turns out the system is more clever that I thought and it never worked from the day I got the bike.

What is supposed to happen:
Front wheel in motion, speed sensor gives input to abs system.
Apply the brake, ABS pump starts to build op pressure until the front wheel stops (no more signal from speed sensor) en then the pump stops and in return the pressure drops.
That is what it does now...


So I can do the happy dance now, took me some time with the volt meter and a stack of wiring diagrams and a proper headache but it works..!!
total cost: speed sensor = 55 euro's

Well found, well done.

Any diagrams etc that might be useful to others will be gratefully received by me via email to include on the manuals pages.

I have a wire diagram for the 250 i.e. ABS for you, will mail it to you when back home this evening.
If all goes well I still habe to recieve a full workshop manual for the same model, but I think that will be in Dutch..

I look forward to both.