Vespa GTS pad & disc change | WORKSHOP
Having just returned from a touring holiday my Vespa GTS was in need of some serious TLC. For 17 days it was loaded to the hilt, ridden two up – both on and off-road and thrashed across England, Spain, Andorra and France. Almost 2,500 miles in total.
Whilst we were away I boiled the rear brake fluid whilst having a bit too much fun on the mega twisty N260 in Spain. The lever came right back to the bars and took a while for feel to return once it’d cooled down a bit. A few days later my rear brake started to grind on another fantastic road, I thought at the time that the heat had warped my rear disc but it seems like the over enthusiastic riding had made the friction material literally drop off the metal pad. I’d only changed them less than 300 miles before the trip. This meant a choice of trying to get some pads and a disc sorted whilst I was away, or leaving metal on metal for the next 1000 miles until I got home. I went for the latter option. Not ideal but I could live with it and just used the rear brake sparingly for the rest of the trip.
Here we are a few days later and I’ve bought a new disc and pads, I’ve also had a new rear Dunlop ScootSmart tyre fitted to the loose wheel. The tyre still had plenty of tread left on it but due to the extra weight, harsh temperatures and hard riding it’d squared off and become a little bit bumpy, so for the cost of a new tyre it was worth changing it whilst the wheel was off.
It’s always better to be safe with wheels and tyres.
If you’d rather just watch the job click the image above, or the following link for a quick time-lapse video taken in the lab. You don’t realise just how much moving about you do in there until you see it in fast forward.
You can see on the photo above (left) that the tyre had started to deform slightly so that the edge of the tread at each sipe was higher on the leading edge. I could feel the vibration getting worse the further I rode but at first I thought it was just the rear disc causing problems. I love the Dunlop ScootSmarts though and fit them to all my scooters.
With hindsight I’d probably have been better off using a slightly harder rear tyre for this particular trip. The new tyre (right) will last me around 4,000 miles in ordinary use, compared to 2,500 during this holiday.
Changing the pads and disc
If you can operate a spanner and follow a few simple instructions it’s not too taxing to change the disc & pads yourself to save some cash.
Firstly you need to remove the exhaust, I’ve got a Scorpion fitted, it’s basically two springs to take off, an allen stud and a bolt. A standard exhaust is similar to remove and should only take five minutes. You don’t have to remove the full system, the manifold can stay in place.
With the exhaust out of the way you can remove the split pin and locking nut cover before undoing the 24mm hub nut. As you’d imagine it’s quite tight and if you’re doing this at home you probably haven’t got an impact gun at hand. So here’s a couple of tips for you…
Tip one: Use a tie wrap to hold the rear brake on, this stops the wheel from turning and makes it easier to loosen the nut.
Tip two: The rear hub nuts are often tricky to remove. In order not to damage your ratchet, fit a breaker bar and use a long pole over the handle to free the nut. Sometimes shocking the handle with a blow from a mallet can help to loosen the nut. If you have a helper they can hold the rear brake on though and also put some weight on the scooter.
With the rear hub nut taken care of you can undo the bottom shock nut and move the shock away from the swinging arm, then undo and remove the two Allen bolts. The swinging arm should be able to be pulled free then. Be sure to catch the spacer though and refit it in the same place.
With the swinging arm removed you can undo the two Allen bolts holding the brake caliper to the engine, allowing the caliper to be pulled free. You can also pull the hub (complete with disc) free at this stage.
Next you need to undo the bolts holding the disc to the hub, it’s easier to hold the disc in a vice (between soft jaws if you intend to use the disc again!) whilst you’re doing this, or temporarily fit the hub back on the layshaft if you haven’t got one.
The pads can be removed from the caliper by pulling the R-clip and sliding the pin out. Check the location of the sprung clip though first so you can replace it with the new one.
Before fitting the new pads you’ll need to force the pistons back into the caliper to make space for them. I tend to temporarily refit the old pads and lever them back against the pistons using a flat screwdriver or spanner. You need as much space as possible to allow the new pads to sit either side of the disc.
Once they’re forced back you can slide the new pads in. I smear copper grease on the back of the new pads to help eliminate brake squeal, I also clean the inside of the caliper using brake disc cleaner. Once the pads are in (remember it’s friction side facing in towards the disc!) you can fit the new spring clip (this has an arrow facing forwards), copper grease the pin, slide it in and fit the R-clip. Sorted.
The new disc can be fitted to the hub, the arrow on the disc needs to face in the direction of rotation.
Slide the hub back over the splines of the layshaft (I cleaned and greased mine first). Then offer up the caliper and bolt it into place. It’s best to pump the rear brake a few times to make sure the disc is sitting properly before tightening the caliper bolts up properly.
Next you can fit the wheel, slide the swinging arm back on and tighten up the rear hub nut (don’t forget the spacer), again use the tie wrap method to keep the wheel still but you also need a torque wrench to tighten it up to the correct setting 77-93 ft-lbs. Always use a new split pin when you fit the locking cover to the hub nut. Finally, refit the Allen bolts, bottom shock nut and the exhaust. Not that if you use a standard-type exhaust then you should fit a new gasket – as shown in this article.
That’s it, job done.
Vespa GTS 300 torque settings
Rear axle nut
Rear shock absorber (bottom)
15-18 ft lbs
15-18 ft lbs