GP Rear Wheel & Brake

[LambrettaMarky]

GP is back on the ramp as I have the MB Scooters Brake Pedal Kit to fit. Don't really like the look of the SIL hardware & the rear brake is pretty poor, so thought I'd do the lot.

I've never removed the rear wheel on a Lambretta, so thought I'd just ask for any guidance & tips. I expect to replace the brake shoes & maybe dress the drum if that will help braking performance, so will pop to Cam Lam for new shoes too.

Thanks in advance for any pointers on wheel removal/rear brake tips..

[L111amo]

Whatever you do don’t fit a mb bigger cam, waste of time, fitted one & took me an age to try & get a good brake, binned it & fitted standard size one & perfect brake straight away

[Storkfoot]

Have you got a hub removing tool like these?

https://jbfab.co.uk/product/lambretta-r ... oval-tool/

https://www.lambretta.co.uk/product_inf ... cts_id=281

You also need a way of keeping the hub still whilst you undo the main nut. Most of us have an old half rim with a “V” shape of metal welded on, or a bit of box section welded on. Anything that’ll jam against the engine casing and stop the hub turning.

If you are going to CamLam anyway, I’d ask them if they have a proper skimming tool for brake shoes.

[LambrettaMarky]

Whatever you do don’t fit a mb bigger cam, waste of time, fitted one & took me an age to try & get a good brake, binned it & fitted standard size one & perfect brake straight away

OK & noted thank you. This is what I have:

MB Scooters Rear Brake Kit. by KTM Marky, on Flickr

[LambrettaMarky]

Have you got a hub removing tool like these?

https://jbfab.co.uk/product/lambretta-r ... oval-tool/

https://www.lambretta.co.uk/product_inf ... cts_id=281

You also need a way of keeping the hub still whilst you undo the main nut. Most of us have an old half rim with a “V” shape of metal welded on, or a bit of box section welded on. Anything that’ll jam against the engine casing and stop the hub turning.

If you are going to CamLam anyway, I’d ask them if they have a proper skimming tool for brake shoes.

Er.... No, No and No half rim either.... I do have a lathe and a mill so maybe I can make something.

I thought this could be a challenge!

Thanks for the tips Paul.

[coaster]

I've got a rear wheel locking device if you want to borrow it and also have an old rim if you want to make your own

Also check out The Steel Weazle (Steve Richards) on Face Book, he did a video on sorting the front brake which has relevance to the rear as well/

[Warkton Tornado No.1]

Normally, however bad the brake, there will be enough of a hold with the foot brake virtually stood upon, to undo the 27 mm nut (normal RH thread) single-handedly with a torque wrench/breaker bar, almost like an imaginary game of Twister. Or - wait for this! - if the cable has been disconnected, a RING SPANNER can be utilised on the brake cam lever to hold the drum

If you have access to a 1/2” square impact driver - & I bet you do - that will also rattle the nut off.

[bookertmgs1]

If you are going to CamLam anyway, I’d ask them if they have a proper skimming tool for brake shoes.

First thing I thought about - espacially as some SIL casing had the misplaced shoe pivot.

Using a skimming tool will significantly improve the brake performance.

I also add a small smear of copper slip on each pivot too when I fit them

[Covboy]

Heres a trick i always use when adjusting the rear brake cable:-

get a large thick cable tie and wrap it around the rear brake arm and casing lug
pull/ tighten it up as much as possible so that the rear brake is fully on
then at the pedal end pull the cable taught and tighetn up the clamp assembly
cut off the cable tie and adjust the final cable tightness/ brake bite with the 10mm nut on the end of the cable

hope that make sense -

[LambrettaMarky]

I've got a rear wheel locking device if you want to borrow it and also have an old rim if you want to make your own

Also check out The Steel Weazle (Steve Richards) on Face Book, he did a video on sorting the front brake which has relevance to the rear as well/

Thanks Colin, but I'll (try to) make something up here & will shout if I get stuck.

[LambrettaMarky]

Making progress. Already have this scissor set up for various locking jobs, so make a couple of spacers and tapped M8 to hold the hub so I could remove the hub nut.

Rear Hub Removal 1 by KTM Marky, on Flickr

All OK & the x3 tapped holes to pull on are M7 - of course they are! Luckily I have a Montesa motor with M7 case screws so I can get around that.

Rear Hub Removal 2 by KTM Marky, on Flickr

Next job is to machine up the puller..

[Warkton Tornado No.1]

All joshing aside, if using the most common type of hub puller that utilises the three M7 holes, try to ensure that there is full thread engagement prior to use. In other words, M7 fasteners that are too long - but equal in length - will be a much safer option than fixings that are too short.

It’s worth running an M7 tap down the three holes to make sure all of the available threads are utilised.

Once the puller is in place & the centre bolt slack removed, a tentative knock with a soft faced mallet will often shock the hub off.

Re-assembly means scrupulously clean & as the taper cone is the driving element, I always apply a smear of Copaslip inside & out, ensuring the cone split is in line with a layshaft spline element, not a groove.

Genuine OEM hubs & matching cones - & no doubt, some good patterns - were always best lapped together with grinding paste prior to fit. Beware of cones that are not hard enough! Over the years, I have bought replacement cones to suit the excellent Serveta hubs but none have ever been of sufficient hardness. The consequences are that the cone shows evidence marks of the spline & the hub loses it’s fit. Even the cones acquired from Scooter Restorations are soft & I am surprised that nobody else has ever mentioned it on this Forum, or - should I say - I cannot ever recall it being flagged up

[LambrettaMarky]

Normally, however bad the brake, there will be enough of a hold with the foot brake virtually stood upon, to undo the 27 mm nut (normal RH thread) single-handedly with a torque wrench/breaker bar, almost like an imaginary game of Twister. Or - wait for this! - if the cable has been disconnected, a RING SPANNER can be utilised on the brake cam lever to hold the drum

If you have access to a 1/2” square impact driver - & I bet you do - that will also rattle the nut off.

Not so sure this brake would be good enough for that - no matter as I have a tool now!

[LambrettaMarky]

Heres a trick i always use when adjusting the rear brake cable:-

get a large thick cable tie and wrap it around the rear brake arm and casing lug
pull/ tighten it up as much as possible so that the rear brake is fully on
then at the pedal end pull the cable taught and tighetn up the clamp assembly
cut off the cable tie and adjust the final cable tightness/ brake bite with the 10mm nut on the end of the cable

hope that make sense -

Yep makes sense - takes the 'slack' out prior to clamping tight so the adjusters can then apply pressure and not use up their travel taking up slack instead..

[LambrettaMarky]

All joshing aside, if using the most common type of hub puller that utilises the three M7 holes, try to ensure that there is full thread engagement prior to use. In other words, M7 fasteners that are too long - but equal in length - will be a much safer option than fixings that are too short.

It’s worth running an M7 tap down the three holes to make sure all of the available threads are utilised.

Once the puller is in place & the centre bolt slack removed, a tentative knock with a soft faced mallet will often shock the hub off.

Re-assembly means scrupulously clean & as the taper cone is the driving element, I always apply a smear of Copaslip inside & out, ensuring the cone split is in line with a layshaft spline element, not a groove.

Genuine OEM hubs & matching cones - & no doubt, some good patterns - were always best lapped together with grinding paste prior to fit. Beware of cones that are not hard enough! Over the years, I have bought replacement cones to suit the excellent Serveta hubs but none have ever been of sufficient hardness. The consequences are that the cone shows evidence marks of the spline & the hub loses it’s fit. Even the cones acquired from Scooter Restorations are soft & I am surprised that nobody else has ever mentioned it on this Forum, or - should I say - I cannot ever recall it being flagged up

Already chased the threads with a taper/plug tap so they are as good as they can be in what feels a pretty light die casting.. I'll use same length set screws to pull them squarely.

I would always lap a new flyweel to the receiving crank taper, so makes sense to get it right here too - can check with some engineer's blue to be sure.

I don't know what I'm going to find in there yet anyhow - it's all new to me!

[Warkton Tornado No.1]

Oops! From the images added, you clearly have sorted out certain of the issues involved with hub removal already

I couldn’t help noticing the earth lead on the flywheel cover. You may never encounter any problems as it is, but there will be many readers that have chased their tails with intermittent electrical gremlins. Chrome or stainless fan covers are not the best electrical conductors, but, no doubt, that arrangement was inherited with the bike.

Personally, an even heavier duty earth strap, such as a car type, affixed to a dedicated tapped hole in the flange of the magneto housing, or even from the stator itself, eliminates any concerns about a good earth twixt frame & engine. Consider it cheap insurance

[LambrettaMarky]

Oops! From the images added, you clearly have sorted out certain of the issues involved with hub removal already

I couldn’t help noticing the earth lead on the flywheel cover. You may never encounter any problems as it is, but there will be many readers that have chased their tails with intermittent electrical gremlins. Chrome or stainless fan covers are not the best electrical conductors, but, no doubt, that arrangement was inherited with the bike.

Personally, an even heavier duty earth strap, such as a car type, affixed to a dedicated tapped hole in the flange of the magneto housing, or even from the stator itself, eliminates any concerns about a good earth twixt frame & engine. Consider it cheap insurance

Eagle eyes.... The earth strap was on one of the mounting screws I had for the Aluminium tray since removed to get the wheel off. Good point about an extra earth & I'll be sure to do that - thank you.

[LambrettaMarky]

and it's off...

Rear Hub by KTM Marky, on Flickr

Worked out the dimensions of the holes & made a test plate to be sure I had them correct:

Rear Hub Test Plate by KTM Marky, on Flickr

Turned up the removal tool, M12 central thread counterbored to clear the threaded shaft and drilled x3 M7 clearance holes on the mill. Turned a 45 degree nose on the M12 bolt to locate centrally on the bub shaft which has a centre drill to locate in:

Rear Hub Tool 1 by KTM Marky, on Flickr

Rear Hub Tool 2 by KTM Marky, on Flickr

Screwed it up reasonably tight and gave it a knock with my mallet & hey presto, off it popped - no drama whatsoever

Rear Hub Tool 3 by KTM Marky, on Flickr

[LambrettaMarky]

Am I OK to keep the scooter held up with a wooden block on the crank case as per my pic' or should I use that funky metal stand thing in my tool box?