Inboard disc help page..............hopefully

[DaveTomo]

On the last forum there was usually a few questions about inboard discs -original & remade.So (again) following on from Martin's BOK here are a few ideas I did to get mine ( a ScootRS remade type) working properly.Please feel free to add to or point out improvements, this isn't a definite guide,just what worked for me.
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When I got the brake and fitted it , it was pretty hopeless, not as good as the drum brake it replaced.No matter how I adjusted it ,normal routing or reverse pull just wouldn't work properly.The quality of the casting (in my case) was spot on, as I'd asked for it in bare metal.Anyway first thing I did was change the bearings & oil seals - there wasn't any real need as they were decent enough Japanese bearings , but I like me FAGs . .Rebuilt it , still crap.Next was change the brake shoes , in my case I went for the Scootopia type others prefer different types such as Newfren,either way you want sintered pads.These needed filing down slightly ,so that they fit loosely in the recess, you don't want to need to force them in,they should drop in.Next the disc,to help it "float" better I removed the circlip, mine doesn't rattle,thankfully.Also on the dowels the disc sits/floats on I cleaned them slightly with a bit of emery cloth, then a very very slight smear of copper grease. Put it all back together still sh*t brake lever not springing back The only thing left was the brake operating arm,reading good things about the Scootopia arm (I'm not on commission honest!) I bought one of these ,because after this I thought feck it I'll put the drum brake back on.

ScootRS brake arm on the left Scootopia on the right.The Scootopia arm alot thicker & the spring under a lot more pressure.

ScootRS arm in situ in the hub, little or no pressure the arm can be pushed near enough all the way across.


Scootopia lever , same amount of pressure,a lot more resistance


Fitted the Scootopia arm, set it up as reverse pull,now absolutely bob on, lever returns and the brake is a joy to use & actually stops you!


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To sum up, there is a cracking guide on here http://www.ilambretta.com/reverse.html on setting up the reverse pull (remember you've got to drill the cable guide on the back plate to 6mm- not as scary as it sounds, and if you want to go back to the standard routing just re-fit the cable top hat).
Remove the anti rattle circlip on the disc itself
clean the dowels & very lightly smear with copper grease
Cable wise I've used a "aircraft grade" cable,but others prefer to use the thicker cable from scooter restos
In the picture I used a purpose bought reverse pull adjuster on the arm, this has now been replaced with a standard cable adjuster off the gear/clutch adjuster block and tapped the the trunnion that sits in the arm out to M7 so that it screws into that.
Also if reverse pull,cable tie (or whatever your preferred method is) the outer cable to the bottom of the fork tube so that it doesn't rub on the bearing cup where the forks meet the frame.
Whichever brake shoes you use make sure they aren't a tight fit,meaning you have to push them in,just lightly file the circumference till they drop in.
You can also drill out the holes on the disc if you need so that the disc floats better,I didn't need to do this.Another guide I found useful as well as the Sticky book was the Lambretta manual of performance tuning and conversions.




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This is meant hopefully to give some people ideas if they're having problems with a disc brake -non hydraulic- as said at the top of the post its not a definitive guide just what worked for me

[HxPaul]

I have a ScootRS inboard disc and have it set up as reverse pull, I had the same problem with the actuator not returning,so I used a compression spring between the actuator and the adjuster,it now returns.I also had other problems with the disc,the main one being the disc pins that the disc floats on were loose.I removed the pins and added loctite,then replaced them.I had to saw a groove in the pins so I could use a screewdriver to insert them.The pads I use are Newfren s2 race sintered pads and I use a thick cable from SR.Since setting the brake up correctly I've done about 3000 miles and it works really well.

[Dimitrios 231]

One more old article.

[bjhart]

I have fitted the new rs disc brake only to experience the same no lever return problems as reported in this thread. I contacted the retailer who advised the rs actuators have recently been improved (still the same length but with a stronger spring) and they duly dispatched a new one. Fitted it tonight and it doesn't exactly snap back but it does just about return. The problem I have now is that I set the static pad and backed it off so just in clearance, then set the cable adjuster so just in clearance. When I pull the lever the pads begin to contact the disc right away causing resistance of the wheel but I can then pull the lever right back to the hand grip....I can't see how this can be adjusted as it seems that the actuator needs further movement to allow maximum braking pressure or am I missing something before I go back to the retailer?

I can only imagine the original actuators have steeper ramps where the balls sit???

[911hillclimber]

This kind of factual reporting is exactly why I joined this forum.

I have done just as said but with the original lever mechanism that is good and free.
Thank you for taking the trouble to post this.

Graham.

[coaster]

I have fitted the new rs disc brake only to experience the same no lever return problems as reported in this thread. I contacted the retailer who advised the rs actuators have recently been improved (still the same length but with a stronger spring) and they duly dispatched a new one. Fitted it tonight and it doesn't exactly snap back but it does just about return. The problem I have now is that I set the static pad and backed it off so just in clearance, then set the cable adjuster so just in clearance. When I pull the lever the pads begin to contact the disc right away causing resistance of the wheel but I can then pull the lever right back to the hand grip....I can't see how this can be adjusted as it seems that the actuator needs further movement to allow maximum braking pressure or am I missing something before I go back to the retailer?

I can only imagine the original actuators have steeper ramps where the balls sit???

Check if there is any movement between the actuator assembly and the retaining circlip. Mine needed some large diameter shims (washers) to take up the slack. Mind you, the grove that my circlip sits in doesn't hold the circlip very well

[Digger]

I had the same problem with the circlip groove not being deep enough on an RS brake. When you pulled the lever the actuator would move rather than press the pad down.

Sold it in the end to a chap who wanted to have a hyrdaulic conversion carried out.

[coaster]

I had the same problem with the circlip groove not being deep enough on an RS brake. When you pulled the lever the actuator would move rather than press the pad down.

Sold it in the end to a chap who wanted to have a hyrdaulic conversion carried out.

That was probably me then, bought off here (I think) about a year (could be 2) or so ago. I did intend hydraulic but thought I'd try it with the cable first as ideally I need the circlip to hold anyway. I've dremelled the groove and it's now stopped jumping out but then noticed the excessive movement hence the washers to pack it out. Brake needs all the other stuff done to it as well yet though.

Great information above btw

[911hillclimber]

I had to fettle the 3 pins and disc holes considerably to get the disc to drop under gravity down the pins to the lowest position.
Pads ended a light filing to remove the black paint and polish the backing disc (Scoot rest sintered pads) I've had to do the same on my huge Brembo racing pads on the race cars, so no big deal.

I think everything is free to float (removed the disc circlip) with a smear of coppers lip on the pins.

When I had my first TV3 in 67 it had a solid disc at 3 years old.....
Even after fettling it was poor, prob the pads back then.

[Digger]

Yes I think it was you Coaster.

[missing lynx]

I may have missed it in the posts but no one's mentioned how vital it is to adjust the floating pad if thats not spot on then no matter how much you mess with the other side it'll never work well

[911hillclimber]

You make a good point.

The static pad has to be positioned 'forward' enough for the disc to make contact AND have some wear allowance too.
I have set mine so the disc is 4 mm off the castings, ie the disc can wear the fixed pad down by 3 mm say before the disc is at the bottom of the pins.

iirc there is about 6mm of friction material on a new pad, so wearing down 50% before considering a change of both pads.

[Revvers]

I'd like to convert my ScootRs inboard disc to hydraulic. How do you go about this and what parts do you need??

[Storkfoot]

Other options are available but my suggestion would be MB housing, Speedfight 100 master cylinder, swaged hose, calliper from CS Engineering which still works fine with circlip.

I am assuming your ScootRS hub works ok?

[Revvers]

Ish....

[Storkfoot]

I have never seen one but I have seen this thread before and others, which is why I asked.

What is the disc like? Does it "float" on the pins OK? Are the pins themselves fixed and rigid (I seem to recall a post saying that one had fallen out )?

Also, how powerful is your engine and have you tried reverse pull yet? For example, I had a pretty fast GT186 on a reverse pull with good "feel" and great stopping power. I doubt, however, this would have coped with my TS1 which is why I have an inboard hydraulic. Both these were on original disc hubs though.

[coaster]

I'd like to convert my ScootRs inboard disc to hydraulic. How do you go about this and what parts do you need??

Keep an eye on ebay, I bought an unused half disc brake that had been made for a hydraulic slave cylinder which is held in place by 2 bolts. With luck I might get it fitted this weekend if mt master cylinder arrives.

[rossclark]

There was an empty one for sale on the FB page for 75£ total bargain.

https://www.facebook.com/Www.jbtuning.c ... ts&fref=ts

[Revvers]

I bought the ScootRs one and to be honest, it's been a lot of messing around. Can't say I'm overly impressed, which is why I was looking at an hydraulic option

[bendyminge]

So glad I read this. I took my ScootRS disc apart for paint and I've been battling with it all night to try and get it back together. The three pins that hold the disc, allow it down about half way and then it just jams. When taking it apart again to retry I have to knock the disc off with some force!
After reading this thread, I'm guessing this is not a new issue and it sounds like I just need to rub down the pins slightly, enough for the disc to drop freely to the bottom of the pins.....is that right?

Ben