new guy looking to rebuild front caliper and master

there's quite a few sources i've found but who do you like for quality, service, reliability and price. this is my virgin foray into norton mechanicals. thanx, rick

rgrigutis said:

... who do you like for quality, service, reliability and price.

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Old Britts rebuilt my caliper. Quite a quick turn-around and a good job, I think. I am going to send them a master cylinder for re-sleeving/re-building, but haven't got around to it yet.

Price ... well ... nothing for a Commando is cheap. My bike (bought from ebay) came with receipts for brake caliper rebuild, but it needed re-rebuilding, so the first, lower-cost rebuild wasn't worth the PO's money.

There is a lot of info and opinions about front brakes. You might want to consider whether you want to retain the stock Lockheed caliper and master cylinder, or whether you'd be better off upgrading. Most people advocate at least sleeving-down the master cylinder rather than retaining the 5/8" bore that is standard.

I also had my brake-rotor blanchard ground by Old Britts. So far, with the refinished rotor, rebuilt caliper and the stock master cyclinder my bike stops OK, but I've never tested it in a "Oh-my-God-I'm-gonna-die" situation.

thanks corona. my sons a tool maker and can grind the rotors altho it won't be on a blanchard. he says he can rotate the rotor 180 and spark out to effect a crosshatch. basically i'm looking for the kits w/ the seals,etc. didn't know about the sleeving down of the lines. old britts is a nice site for a new guy like me so i guess i'll give them a call.

If you plan on rebuilding the calipers yourself then there are a couple of sources for parts. My opinion is Old Britts and Fair Spares are the best bets. Both Fred Eaton and Phil Radford have a wealth of experience and information. You will need to buy or make a plug removing tool. If the caliper is siezed (mine was) removing it can be a difficult task.

Here's a good (I think) link for Commando parts and info.

http://www.nortons.dk/links/

Bear in mind, the author is in Denmark so most of the sites he links to are in Europe.

If you don't have a shop manual, a parts book and a copy of INOA "Tech Digest" then you should get one of each (IMHO).

Good advice times three.

...make it four.

I went with a Gremica 2 piston caliper, Gremica 11mm master and a 12" floating disc. Makes for a damn good single disc stopper. What ever you do, try to achieve a 27:1 ratio between caliper and master. This is per Mike Morris of Vintage Brake. I doubt there is anyone who knows more about motorcycle brakes.

The front brake rebuild is the next item on the list. I'm gonna take it apart and see if it's just plain O-rings and replace them.

If a piston(s) are being a PITA to remove just take your grease gun and open the zerk fitting and pump them out. The grease gun is MORE powerful than compressed air, less dangerous then compressed air and a good cleaner and lube for the bore.

Chopped, Kinda made me laugh when I read your post, A friend of mine was trying to remove the inner plug from a caliper with compressed air and when it finally let loose it went halfway across the room. He had it pointed the right direction but wanted to see if the plug was moving and that is when it broke loose. On its way it just missed his head by a inch, He said he felt it go by. The look on his face was priceless, As we know the weight of the thing would have really done some damage. Your idea about the grease gun sounds like it surely would be a lot safer and would work great. It was one of those moments where we both said that was stupid.

A good tip for removing the blanking plug & the caliper pistons is to warm the caliper gently with a blow lamp, to a temperature that is reasonably hot to the touch.

The inner piston can be gripped with 2 combination spanners, ring ends back to back in the recess. Squeeze the other ends together & they will grip in the piston & it will easily come out.

Try it & see how easy it can be.

I would recomend new pistons in Stainless. I got mine from RGM. Reasonably priced & good quality.

Bob.

I was smiling reading about using high pressure air to remove a stucked piston and what will happen if it works

Old Britt is recommending this procedure, I don't know why, if you give it a little thought it is rather obvious that it is dangerous. I sent them a mail telling them that their procedure is unsafe and they should recommend using a grease gun instead. Got a response they will consider it.

The grease gun method is safe, lubricates the piston at removal, cleans out the crap in the caliper and avoiding scrathes is the caliper bore.
I'm not aware of any better way of doing it.

I used SS pistons from RGM and also did their re-sleeve mod for the master cylinder and the result is a well working front brake.

Cheers,
Per

what's the purpose of resleeving?

rgrigutis said:

what's the purpose of resleeving?

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By reducing the ID of the master cylinder you increase the pressure applied for any given lever force. So, you don't have to squeeze desparately to apply a force at the brake. Because you can apply gradual finger/grip force, you can control the pressure better. This allows for more controlled and gradual braking and better feedback.

The Vintage Brakes website recommends a ratio of 27:1 for the caliper-area to master-cylinder-cross-sectional-area ratio. Per Vintage Brakes, a ratio of less than 23:1 feels too "wooden". He says: "I think ratios lower than 23:1 produce a lever feel so "wooden" as to have little, if any feel. Combine "low" leverage ratios with sticky pads, and unpredictable lockup is the result."

The standard 5/8" Norton Lockheed master cylinder with the 41mm calipers gives a ratio of 13.3:1.

So that's why many folks resleeve to 13mm (usually) or replace the master cylinder. Some prefer 11mm (see Rocky Point Cycles website) which gives the "ideal" 27:1 ratio with the stock caliper.

If you search this site for brake modifications, master cyclinder, or similar terms you'll find oodles of info about the various brake set-ups that others have put together.

I am personally in the process of changing to a brembo caliper with a 13mm master cylinder (which will give a ratio of 24.3:1) but I've been dragging my feet a bit (still undecided on which disk to use). Presently, as I said in a previous post, my stock set up will stop the bike OK, but it is lacking in feel and I do ride very conservatively and keep my distance because I don't want to have to stop in a hell of a hurry (I am not conifdent that it would!)

Hope this helps. But use the 'search' facility because almost everything you need to know has been discussed on here lots of times before.

You can spend a lot of money on disc brakes, but the best money spent is achieving a 27:1 ratio. However you get there.