LCGB Forums

This is the hydraulic brake slave cylinder on a GP I am working on. I have not seen one of these before can anyone tell me what make it is please? Also it looks to unscrew from the hub is this true. I have tried to unscrew it but it would not budge so I thought it best to ask. The rectangular hole is where someone has cut off the cable mounting.

Another interesting thing about this scooter are the rims. They have been made for 4.00 x 10 tyres

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There were many versions of hydraulic conversions to the standard disc brake.

Most screwed in, but it is not clear from the image you posted whether that is the sort you have, although you say it looks to be that type.

If you can see a thread on the slave cylinder, then it will be.

The ‘World & His Wife’ may have made yours, but hopefully, it will prove to be a good version, worth saving.

Until you establish whether it is a screw in type & if so remove it to strip it, it is not possible to tell what make it may be. With luck, it could be an MSC which were the best, in my experience.

Copious amounts of penetrating oil (NOT WD40 or GT85) will help after soaking for days. Gentle heating of the housing (NOT THE SLAVE) will also encourage it to free up.

On one of mine, I machined two flats so that I could hold it with tools, but I made sure one of the flats served the dual purpose of giving the additional clearance needed to the damper when braking hard & the front wheel is hopping….

When you come to re-assemble, don’t let anybody tell you to leave the slave not fully tightened & free to revolve in the threaded housing as was the practice years ago. Many of us did that but it fractures the housing. It’s best to use a low strength Loctite & screw in until it bottoms out.

It sounds like you may have early wide rims. Before being commercially available, racers used to convert V*spa rims. The very thought of it makes me shudder….

I am told by the owner, an Italian barber, that this scooter was owned by the son of the Casa Lambretta museum owner and was intended for his use but decided to sell it. It has a TS1 engine but not run for over 2 years and lost its spark.

That back plate was originally made in Italy alright. The conversion would have been done here, though. That is an ex-race brake, I would imagine.

Looks much like my MSC DJ one but lots of people made a similar disc at this time. Yes, the cylinder screws in/out but DO NOT force it as you can quite easily break off the thin wall of the hub! You'll need to soak this in WD or something else for a while... perhaps submerge the whole thing in diesel for a week?

If you get it apart then you'll need to examine the piston, hoping it is in there, to identify how it is machined, who made it/sold it, and what seal is required. The MSC DJ ones use an obscure French car seal that is now hard to come by. Others seem to have used different seals in their pistons. If the internals are too corroded then you may be looking to source a new cylinder and piston (and seal) so that it is hydraulic seal tight.

Best to strip it, carefully, then examine and post photos for people to help identify.

Adam

PS - These work extremely well when built correctly, so much so that Tino has an inboard offering available.

Looks very similar to one I have that is alleged to be by Taffspeed.

It uses a mini / metro piston and seal from the four pot caliper.

It was a pig to get out originally and I used a longish bolt in the bleed nipple thread as a lever to get it turning.

Thanks for that information it may be useful if I need a seal. I have tried gripping the cylinder that is sticking out in a vice then warming the casing but it won't move with a fair bit of effort.

Soak it. Force is very likely to get it to break along one of the machined thread lines, then it'll be fit for the bin!

I have one similarly seized and over the years have tried heat, various releasing sprays, soaking, all to no effect.
I have just about given up on it, but have a friendly precision engineer as a last ditch solution. He has said that if he breaks it or it is still seized then he can fabricate a new slave cylinder or weld a section of threaded tube into the backplate housing, so it might be worth rescuing in the future. In the meantime, I bought a replacement from MB that he had already converted.

It's not leaking so I'll leave well alone and not send it to the blasting shop I'll rattle can it.