cable operated front disc poor performance

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tavspeed
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Hi,chaps a mate has just bought a tv175 with a repro front disc, cable operated, in reverse pull style.with everything properly adjusted the brake lever is hitting the grips before any braking happens,we have put new pads in etc.
the actuator seems a very sloppy fit in the backplate,and the actuator arm travels quite a lot before exerting any braking force.
we are also having problems with the speedo drive,so is onabout getting a new one from ebay.
what is the braking performance like with the reverse pull set up or is he probaly better going hydraulic,cheers all
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HxPaul
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Main scooter: lambretta Li 150
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tavspeed wrote: Tue Mar 19, 2019 10:42 pm Hi,chaps a mate has just bought a tv175 with a repro front disc, cable operated, in reverse pull style.with everything properly adjusted the brake lever is hitting the grips before any braking happens,we have put new pads in etc.
the actuator seems a very sloppy fit in the backplate,and the actuator arm travels quite a lot before exerting any braking force.
we are also having problems with the speedo drive,so is onabout getting a new one from ebay.
what is the braking performance like with the reverse pull set up or is he probaly better going hydraulic,cheers all
I have an inboard disc with reverse pull.On the stand it feels very woolly,but out on the road its really good.I'm running mine with the proper cable and Newfren sintered disc pads.
Mrnice71
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Is the disc fully floating? Has the disc got a circlip in it ? If so remove circlip and make sure disc is free on pins .
Are the pads tight in the housings ? Also the cable needs to be as short as possible in fact nearly to short for it to work correctly reverse pull . Converting to hydraulic will improve it but the main problem will always be the pads are small .
l personally would cut your losses & buy an outboard , the ones with the Nissin calliper are very good indeed but if costs are not an issue go with a casa one which is a great piece of kit .
tavspeed
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yeah disc floats on pins,even tried a new actuator,with everything adjusted up so the disc is slightly rubbing on the pads, the brake lever is hitting the handle bar grips,due to the travel in the actuator arm.
you can also just move the wheel with your hand when the lever is back to the grip.
due to issues with the speedo drive he has ordered a new front hub disc,but i am worried it will have the same issues,i will let you know how we get on,cheers all
rosscla
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Some of the circlips are very soft and this can cause some flex and sponginess
"Our dilemma is that we hate change and love it at the same time; what we really want is for things to remain the same but get better."
Warkton Tornado No.1
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To obtain the best performance from the mechanically operated OEM disc brake, IMHO sintered pads are a must, as is reverse pull.

There is no need to remove the anti-rattle circling or enlarge the disc holes for the three pins as long as assembly is meticulous with the use of an anti-sieze grease such as Copaslip.

Because the actuator is a cam, effectively, via the ball bearings, my experience is to eliminate as much clearance as possible via a little lateral thinking.

I'm not very keen about the standard static pad adjuster, so, certainly with hydraulic conversions, I fit large shims under that pad to bring it closer to engagement with the disc. That process can be used regardless of the operation.

The actuator can also be moved closer inboard by the addition of a shim between it & the circlip though I really stress that everything should be well engineered. A shim may look like a washer, but it needs to be hard steel, preferably ground flat & fit the hole tightly that it needs to operate within.
challenger
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I had the same problem with a new scootrs remade internal disc.
The spring on the actuating arm was to weak. After swapping it for a new one, the brake worked fine.
The problem with the actuator was known about at the time, my shop exchanged the part frees of charge.
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