Specs for Brembo Steel Rotors

[canuck750]

I have a couple of original Brembo rotors that I want to have checked over and cleaned up on a brake lathe.

The local brake shop wants to know what the rotor thickness specs are before they will turn them.

Anyone know what the wear limit thickness is for the steel rotors used on the 850T3 type bikes.

Thanks

Jim

[crc]

not sure but I bet its in guzzioligy

[Hahnda]

I believe its 5.8mm min thickness.

[mtiberio]

it is usually stamped on the rotor somewhete, sometimes on the outer periphery (the ~6mm wide part). I know you do not want them any thinner than 5mm. I'd tell them to take out any warp (or gross thickness variation), but do not try and remove all score marks.

[Mike Tashjian]

An automotive machine shop with a Blanchard grinder gives a great finish and can take off the bare minimum.  Ask around a bit before committing to a brake lathe.  Mike

[Don G]

Grinding would be the best , I have found that turning rotors that thin on a brake lathe just dont work out, due to vibration I guess.  DonG

[JoeW]

Jim, I tried all to machine Brembo rotors on my Ammco brake lathe, I even spent 800.00 for a three jaw holding device and still got a chatter once I got past half way out. I used anti-vibration bands and even a 2x4 along the outer edge until it started to smoke! I highly recommend you send them to Tom at http://www.truedisk.net/ I've had several sets done by him.
I've got a set at the powder coater I'll post pictures when I pick them up.

BTW min thickness is 5.8mm

[canuck750]

Thanks for the info Joe, I will look him up.

Did you powder coat after the disc were trued or before?


Cheers

Jim

[JoeW]

Thanks for the info Joe, I will look him up.

Did you powder coat after the disc were trued or before?


Cheers

Jim

After, I'm picking them up Monday I'll let you know how it worked.

[Groover]

I also want to know this and I'm also going to get them powder coated. Is "grind" a service a rotor turning place provides? What should one expect to pay to get the rotors powder coated and ground?

I understand it will vary, but just an approximateidea would be good.

Looking forwars to more pics!

[JoeW]

I also want to know this and I'm also going to get them powder coated. Is "grind" a service a rotor turning place provides? What should one expect to pay to get the rotors powder coated and ground?

I understand it will vary, but just an approximateidea would be good.

Looking forwars to more pics!

The rotor grinding was about 50.00 per rotor plus shipping. I haven't picked up the powder coat yet so, I don't know how much that'll be.

[guzzista]

 :+1 on truedisk s'matter of fact I had already recommended them on a previous post. As for powder coating , it will look great, but for the more parsimonious folks , cast iron is excellent for paint retention once it is clean and that good quality paint applied correctly will last a long time

[JoeW]

FYI powder coat is not impervious to brake fluid. I'm just hoping it cleans up easier than paint.

[canuck750]

I sent an email inquiry to True Disk about accepting work from Canada, they got back to me right away and have no problem accepting work from across the border. I stripped the discs of my 750 S3 this afternoon and will mail them off tomorrow. Thanks for the link these guys sure seem to know what they are doing and even with shipping the refurbishment will be much less than new discs.

The local NAPA shop sells a brake caliper paint that I ,ay give a try on the rotors once I get them back. I don't know for certain but I am guessing this high heat caliper paint is resistant to brake fluid.

Jim

[Stevex]

My LM2 front disc carriers have 'Minimum 5.8mm' stamped on them.
Just gone to stainless all round as the fronts were at minimum thickness and warped.

[canuck750]

My LM2 front disc carriers have 'Minimum 5.8mm' stamped on them.
Just gone to stainless all round as the fronts were at minimum thickness and warped.

Thanks!

I checked the edge of the rotors, sure enough each one is stamped min. 5.8mm. All of them measure up well within tolerance so I cleaned them up in the bead blast cabinet and now they will be shipped off for grinding, then powder coating.



I pulled the calipers off the 750 S3 while I was at it, may as well do the 850T and the S3 at the same time.



Just like the T brakes, the S3 had at least one seized piston in each caliper, the hoses are very soft and the rear master cylinder is in serious need of a rebuild kit.



40 year old brakes and modern traffic, not a good mix!

[rodekyll]

FYI powder coat is not impervious to brake fluid. I'm just hoping it cleans up easier than paint.

It depends on the powder.  I've had a sample soaking in brake fluid to see if I can use dot3 as a remover.  No joy.

[crc]

I hope youre going to go with anodized pistons jim?

[canuck750]

I hope youre going to go with anodized pistons jim?

Absolutely! and new Brembo seal and pin kits.

Stopping is more important to me than going fast. :)

[JoeW]

The rotors are back from the powder coat shop, I don't have a break down on price yet but, they look awesome....



The last shot shows the 10mm spacer for adding a second disc to and Eldorado using a Tonti spacer.

[Groover]

Very nice, thanks for posting!

[canuck750]

WOW, those look fantastic Joe, hope to get mine to that condition. I am expecting to get my rotors back early next week.

I am going to try my DIY home powder coating kit on the rotors, I am too cheap to spring for a professional powder coater.

Cheers

Jim

[mtiberio]

nice example of the original brembo cast rotors, not the later guzzi made (I believe) stamped rotors. the brembos might have been stamped, but then must have been forged to get the I beam (or H beam) cross section on the webs. The later rotors definately showed the break and shear associated with a metal stamping.

[canuck750]

I got the five rotors back from TrueDisc yesterday, extremely well packed in between sheets of polystyrene. The service has been fantastic, considering mail shipping from Canada to the USA and back, simple payment by PayPal and they look great.
Three of the rotors are off the 750S3 and the drilled ones of a 850T. I am going to send these to a pro for powder coating, too much to mask with heat tape and try to fit them in my wall oven.







Thanks Joe for recommending these guys, I will definitely be using them again.

Rebuilt the three 750S3 calipers, and I found a set of new braided hoses from HMB in Germany, just need to fit the rebuild kits into the master cylinders and the 750S3 will have like new brakes.

[rodekyll]

Rotors should be no problem diy.  They're easy and a great learning tool/confidence booster.

They need to be surgically clean -- blast with your favorite media, rub with a red skotch pad and wash wiht laquer thinner untill the paper towel comes clean.  Figure out how to suspend them for access as you coat and bake BEFORE going clean.  I'd suggest hanging them from a wire if you have oven enough, or using three of your long hub cross bolts and pairs of nuts to make standoffs.  I use two long pieces of all-thread and string them up together -- keeps them from swinging and hitting each other in the oven.  Use green tape and baker's parchment paper to mask, don't open the oven while the process is running, and get the tape off while it's still hot.

Here's a diy powder coated Honda rotor on a powder coated Guzzi Lester:



Canuck -- I'll mask and shoot those.  PM me.

[canuck750]

That's sure generous of you Rodekyll! but you have encouraged me to give the DIY a try in my oven.

For masking I found a white fibre high heat tape, I think it's for wrapping generators and similar electrical components, never thought of the parchment paper, if its good enough for baking a cake then it should be find for the rotors.

There is a remnant of old paint on the rotors that was very stubborn to the glass media, must it all come of or can I powder over it?

Thanks for the help and encouragement!

Cheers
Jim

[rodekyll]

I try to completely clean them.  Get some carb cleaner or a dab of paint stripper on it and see if you can coax it out with a wire brush.

There is special silicone tape made for powder coating.  It stands up to the temp and doesn't gassify into the oven.  It comes in two flavors -- green and orange.  I've tried to beat their prices by using other kinds of tape and they just don't work.  They either shrink, burn, or permanently adhere to the part.

There are also silicone plugs made to mask studs and holes.  If you need to protect features on parts, a selection kit of these is invaluable.  I buy kits of a dozen or so sizes of innies and outies.  They save a lot of time and cussing.

[canuck750]

I try to completely clean them.  Get some carb cleaner or a dab of paint stripper on it and see if you can coax it out with a wire brush.

There is special silicone tape made for powder coating.  It stands up to the temp and doesn't gassify into the oven.  It comes in two flavors -- green and orange.  I've tried to beat their prices by using other kinds of tape and they just don't work.  They either shrink, burn, or permanently adhere to the part.

There are also silicone plugs made to mask studs and holes.  If you need to protect features on parts, a selection kit of these is invaluable.  I buy kits of a dozen or so sizes of innies and outies.  They save a lot of time and cussing.

Thanks!

I will shop for some 'green' tape on Ebay this evening, the white fibre tape is a bitch to get off unless I peel it off when the parts are still hot. I bought a bag of silicone plugs with the DIY kit a couple years ago, great for plugging holes. I really need to build a larger oven, the 40m year old wall oven is pretty small and bot too tall. The paint on the rotors is really baked on, I tried paint stripper, wire wheel and glass bead. I need to find a stringer stripper product, there are powder stripping chemicals available but its very expensive.

Cheers
Jim

[rodekyll]

You might try precooking the rotors at 15º above what the cure needs for about 15 minutes (time with part at temp).  If that doesn't loosen the paint specks to the point that a wire brush/carb cleaner will dislodge them, then they will probably withstand the cure.  My problem with the contamination is that the powder might not bind to it.

Green tape is easily bought through caswells ( iavoid -- won't ship to AK -- but might ship to Canada), powder-buy-the-pound (my go-to), and Rosie's powdercoating (excellent tech support and dummy questions answered without making you feel dumb), to name three outlets.  They come in a variety of widths.  The red stuff is for higher temps than you are probably cooking at for rotors.  None of this stuff goes around corners or stretches well, so I try to lay straight tape and then xacto-knife the curves.  The parchment paper works good for masking wide areas. 

I try to buy another cup for the powder gun whenever I place an order, since the shipping rates for some of these places depends on items bought, not actual shipping weight.  For example, I just bout a pound of black and a pound of white super-durable powder.  It's $11.95 to ship those two pounds.  Adding the cup doesn't change the shipping, and they're cheap.  You can't have too many cups.  I keep a filled one in the box with the powder sack of the same color and try to add as my color library grows.  It saves 10 minutes/color change when you don't have to sanitize the cups, and if you keep the same powder in the same cup you don't get rogue specks of the wrong color in the finish.

Remember -- for most powders, clearcoat is your friend.  I use a zero%-gloss or glass-finish clear when all I want to do is make the powder more durable -- for example, if I want a dull, dry, blasted aluminum look.  I use diamond and other glosses up to 100% for blingy stuff.  I sometimes shoot clear over bare aluminum cases if they cleaned up perfectly.  Superdurable powders do not use clear.

[canuck750]

I searched for Powder Coating supplies and lo and behold Cloverdale Paint here in town stocks the translucent green high heat masking tape (no red though), they had many different widths in stock, bought a couple different sizes. I am going to try heating the rotors up to 400 F and see if the remnants of old paint peel off. If that works I will rig up some kind of hanging rack that uses the through bolt holes and see how that works.

Do you apply the clear powder over fully cured and cold base colour or do you spray the powder when the parts are fresh out of the oven? I have never applied a clear coat over any parts I have powder coated nor have I applied clear over bare aluminum but I like the idea of clear coating the wheel bearing carriers and other parts that take a lot of abuse.

Jim