Disk Brake

Read all the threads about fluid, still do not see a consensus which is best. I like the fact DOT5 will not harm paint, but the corrosion problem scares me. DOT 3 or DOT4 sound like either is fine? I totally rebuilt my Master Cyl and Caliper, along with a new SS Hose. Another Q coming up shortly: My disk rotor is not grooved, and I assume it is factory original cast iron? It has taken on a copper color. Is it alright to just scuff it up somewhat, and if so what pads can I use?

the dot 5 has its own share of issues and I would NOT recommend it in something you plan to ride very hard. last I heard most racing organizations will not let you use it either. I would use dot4 LMA and do a change and flush once a year if you live in a high humidity location. the LMA means it is low moisture absorption.

DOT 4, flush bi-annually. Lather rinse repeat. I had DOT 5 on a few bikes for long term the corrosion nearly ruined all the expensive brake/clutch parts. Seams the claims of long-life were overblown.

DOT 3 and 4 are the standard fluids and can intermix and match. They tend to absorb and collect water more than DOT5 so change it now and again, before water layer collects on rustable parts. DOT 5 is mainly used in long stored vehicles. Can search up the downsies to each of these but all can have been used fined in Commando, though racers aren't using DOT5.

What is the recommended procedure to refurbish the rotor? I will track down some DOT Low Moisture Absorbsion fluid! I do not plan to ride much, let alone brake any speed records so I was planning to use the cheaper brake pads, thinking they may wear into the old rotor. Cartel makes a DOT4 LMA Silicone Brake Fluid, any thoughts on it?

My front rotor has the same copper sheen you speak of. Years ago I replaced the original one and the pads too. I think the metallic mix in the compound of the pads is copper and gets transfered to the rotor some but aside from looking a little strange doesn't seem to matter. I'd just scuff up the rotor with a green Scotch Brite pad ( it's pretty hard) and install the new pads. I use dot 3 or dot 4 brake fluid and mostly follow the drain & flush routine but just every once in a while (should do it more).

Thanks All! Will be shopping for Castrol DOT4 LMA, should not be too hard to find. Also not to be concerned about my rotor, can be scuffed. I need more research on pads.
Parts came today, Hose was rubber! Three suppliers I am setup with, all do not have Stainless Hose. No luck finding one in USA.
New Question: Found a company called Earls Performance, they make hose and fittings, looks like they are hooked up with Holly Carburetor's. Has anyone done anything like this? When I get to rebuilding my Amal's I would also like to use Stainless Steel lines

mooskie said:

Thanks All! Will be shopping for Castrol DOT4 LMA, should not be too hard to find. Also not to be concerned about my rotor, can be scuffed. I need more research on pads.
Parts came today, Hose was rubber! Three suppliers I am setup with, all do not have Stainless Hose. No luck finding one in USA.
New Question: Found a company called Earls Performance, they make hose and fittings, looks like they are hooked up with Holly Carburetor's. Has anyone done anything like this? When I get to rebuilding my Amal's I would also like to use Stainless Steel lines

Click to expand...

I've used Earls fittings since the '70s for oil and brake lines. I use the Speed-Flex -3 hose and Speed-Seal hose ends for brake and clutch lines, and the Perform-O-Flex -6 hose with Swivel-Seal hose end for oil lines. You will need to use adapters for the Norton master and slave cylinders to accommodate the AN style fittings. Earl's was an independent business for at least a couple decades, before being bought out by Holly. You can find similar style AN hose and fittings from Aeroquip and Russell, and probably other suppliers. Just google "AN hose fittings" for options.

Ken

I have always used the DOT 5 fluid because I think I was told that the rubber parts would be destroyed by using DOT 3-4.
Was I mislead?
If I was to go with DOT 3-4, what would I have to do the the system? Tear it apart and put in new rubber?

Guido said:

I have always used the DOT 5 fluid because I think I was told that the rubber parts would be destroyed by using DOT 3-4.
Was I mislead?
If I was to go with DOT 3-4, what would I have to do the the system? Tear it apart and put in new rubber?

Click to expand...

Yes. Nothing. No.

Norton Lockheed seals were born and raised in DOT 3 and DOT 4 is a close sister. One can't keep to0 clean nor too fresh a brake system so yest flush out with 3 or 4, mixing and matching is fine, then top off with either and squeal away. Do note that old stored DOT 3 or 4 tends to pick up moisture and certainly in the brake system and don't know if just heating to boiling can drive off the oil bond moisture, but risk is more of rusting steel items than pockets of steam causing fade till you squeal.
Acetone in DOT 3-4 is its main risk in using.

I'm surprised that no one has mentioned DOT 5.1, a close cousin to DOT 3 & 4 but less hydroscopic and has a higher boiling point, I change it out every 2 years along with the fork oil; gives me an excellent opportunity to check pads, steering head bearings and wheel for true/balance.

I used DOT 5 years ago on a Fiat X 1/9 brake and clutch systems, it seemed compresible which gave me a bit of extra modulation for the brakes, but it turned jelly like after about 3 years. Harleys used DOT 5 up until recently and caution against switching to any glycol based fluids. Anyone know why you can use DOT 5 in a system specified for DOT 3 & 4, but not the other way around?

Bill.

Brake systems older than 3 decades may still have some natural rubber parts which Dot 5 can eat up as the main issue to beaware of. DOT 5.1 is thinner than 3 or 4 so was made to help the fast acting ABS systems work better but not necessarily our non ABS brakes. I can not online anything that said a gelling issue of mixing 5 with others, just more prone to collect pure water pockets at bottoms of lines and calipers for lower temp to vapor and spongy feel if really racer heating. DOT 5 is lighter than 3 - 4 -5.1 so flushing by filling top and draining don't work well as the DOT5 bubbles to the top while the other fluids run through to the drain exit. Essentially all systems which DOT 5 is intended are brand new and only ever filled with DOT5. Essentially all systems designed for DOT5 only are "Sealed" not vented like ours to help keep out water, otherwise may need to change - flush out like the other fluids to keep dryer. Only reason to use DOT 5 is for museum, show and military equipment that sits up look periods and is safe for fancy paint job$. Here's a blog that covers the above with a few more points of alerts. Oh yeah they say don't put DOT3 in DOT 4 but ok to put DOT 4 in DOT 3 filled systems, but that's only because you lower the boiling point a bit with DOT3 added to DOT 4, BFD, unless you can brake so hard and often you heat to point of fade.
I thought i'd run into this on Trixie, after a rotor pad sanding and refilling and tying lever back over night, took off to pavement and got tire lock fine - for 3-4 pull downs then no matter how hard I squeezed, no squeal and rather longer slow downs, ugh. Did this for some hours on-off and never got it to stop dramatically fading after a few Hard pull downs, but next day I could not induce any fade at all so assume just residual air or moisture worked out and that was that.

http://forum.miata.net/vb/archive/index ... 60254.html

British Cycle Supply sold me a Goodrige Brake Line that I cut to length. Finished brake system test yesterday and tested it in the basement. 3deg F outside! I really like this! Came from Canada via dog sled, as it took forever but worth it. I did make a mistake and used grease to put the seal on the master cyl piston, learned later to not introduce anything to brake system as can cause early failures.

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lcrken said:

mooskie said:

Thanks All! Will be shopping for Castrol DOT4 LMA, should not be too hard to find. Also not to be concerned about my rotor, can be scuffed. I need more research on pads.
Parts came today, Hose was rubber! Three suppliers I am setup with, all do not have Stainless Hose. No luck finding one in USA.
New Question: Found a company called Earls Performance, they make hose and fittings, looks like they are hooked up with Holly Carburetor's. Has anyone done anything like this? When I get to rebuilding my Amal's I would also like to use Stainless Steel lines

Click to expand...

I've used Earls fittings since the '70s for oil and brake lines. I use the Speed-Flex -3 hose and Speed-Seal hose ends for brake and clutch lines, and the Perform-O-Flex -6 hose with Swivel-Seal hose end for oil lines. You will need to use adapters for the Norton master and slave cylinders to accommodate the AN style fittings. Earl's was an independent business for at least a couple decades, before being bought out by Holly. You can find similar style AN hose and fittings from Aeroquip and Russell, and probably other suppliers. Just google "AN hose fittings" for options.

Ken

Click to expand...

Are you just looking for the brake lines for one bike or are you looking for coils of the appropriate size ss? If for coils, as noted, Earls probably has it/do the search for AN lines. If you just need the appropriate SS lines for your own bike, Old Britts has the SS lines with fittings so they are just "plug 'n play" after removing the old lines.