stainless brake pistons

[britlude]

hi, i've decided my front brake pistons are past it, and i'm looking at putting stainless ones in!

mine is a 1992 NA1, so has the 36mm and 40mm pistons up front and they are getting crusty. has anyone sourced stainless ones already???? if so where from?

lings list stock ones at £80 a pop, so i've asked BiggRed and Auto Component Supplies if they can supply them (as they list the rubber overhaul kits)

also asked Godspeed Brakes and Kitek as they specialise in stainless caliper pistons for other marques. Kitek looks good on specials pricing too.... http://www.kitek.co.uk/wordpress/?page_id=30

what i do need tho (see, on the want!) is some dimensions (or samples to measure) to save me taking my calipers to bits and having the car immobile.... i know the outer diameters, but need the overall lengths and the position/depth of the seal groove.

if all else fails i'll just get a bit of stainless bar and whittle some on my lathe!


(rock auto had ordinary pistons listed in their brake section, but when i clicked to add the item, it said 'not available, deleted from basket', then deleted it from the parts catalogue too!!!! quite annoying as they were about £6 each!!!)

[Kaz-kzukNA1]

Hi, Jonathan.

I have used, rusty OEM pistons so if they are the correct spec (40/36mm), you can have them.
I'm quite sure I have 40mm one but not so sure about the 36mm as most of the recent brake caliper overhaul including mine were for the later spec ones (40/34mm).
Also, I need to check the conditions as the rust/corrosion may went too far and may not be suitable for taking any measurements.
Depending on the spec of stainless you are going to use, you may need to measure the internal bore size of the caliper cyl/body any way in order to check the OEM clearance requirement.

I'm too busy this week sevicing the NSX as I'm already well behind the schedule so you may need to wait until latter part of the week before I can visit the post office.
Alternatively, if you happen to be visiting Silverstone or nearby for any events, please feel free to drop by at my place.

Kaz

[britlude]

thanks for that Kaz, if you could have a look to see if you have a pair that would be appreciated.

I'm waiting on replies from vendors, if/when they reply!

i'm sure Biggred has the dimensions already, they have seen one or two NSX brake calipers already!!! but it depends on their pricing and if they are stainless!

kitek should be £102 for the front 4 pistons, according to their site pricing

then again 0.5m of 50mm stainless round bar is about £30, and i do have a lathe... :)

[britlude]

kitek reply...


Hi Jonathan

Yes, we can supply pistons for your car.
I will need an old piston for a template – it doesn’t matter how bad they
are we can collect the details we need.
It takes about 10 working days – 2 weeks from receipt of pistons and monies.
The cost is 0.75p per mm diameter of the piston, per piston.
So if the diameter of the piston is 30mm and there are 4 on the front axle
then the cost is;
0.75 x 30 = £22.5, x 4= £90.00 for the set of 4. This is all inclusive (in
the UK, surcharge of £10 for outside UK).
If there are two different sizes of pistons then the same formulae apply for
each.

price risen a bit from their website, so 0.75x40 plus 0.75x36 x2 for both sides = £114 all in.... better than the HUK price.... but no surprise there!

[britlude]

Godspeed have got back to me, approx £25 each replicating supplied samples....

So unless I hear anything different from the other 2 companies I'll be buying myself a chunk of stainless and making my own replicas! I can strip mine, repaint them, and while waiting for the paint to dry I can turn up some new pistons... And save down time!! :)

And it'll stop me getting bored, we know how dangerous that is!!!

[NSXGB]

When are you starting taking orders!?



Godspeed have got back to me, approx £25 each replicating supplied samples....

So unless I hear anything different from the other 2 companies I'll be buying myself a chunk of stainless and making my own replicas! I can strip mine, repaint them, and while waiting for the paint to dry I can turn up some new pistons... And save down time!! :)

And it'll stop me getting bored, we know how dangerous that is!!!

[mutley]

Jon,

you could make a fortune suppliying all your little mods, at some point I'll be trying to replicate your LED DRL/side lights/indicators idea.....although I'm more of a mech than an elec type!

Chers
Jim

[britlude]

latest update...

BiggRed says go to honda for the pistons.... odd for a caliper refurbishment service!!!!

jp-carparts.com .... all the parts available (i put in a prelim order for the seals/rubber bits and pistons) except one rubber and one of the pistons which are on a 3wk back order lead time!

..... a chunk of stainless steel will be on its way shortly!

[NSXGB]

Jon, I have a set of non Honda seals you can have if you want them - FOC.



latest update...

BiggRed says go to honda for the pistons.... odd for a caliper refurbishment service!!!!

jp-carparts.com .... all the parts available (i put in a prelim order for the seals/rubber bits and pistons) except one rubber and one of the pistons which are on a 3wk back order lead time!

..... a chunk of stainless steel will be on its way shortly!

[britlude]

tell me that just as the paypal has been fired off!!! lol

thanks for the offer anyway :)

[britlude]

the new stainless brake pistons have arrived, in their original packaging....

http://i301.photobucket.com/albums/nn41/thisYup/from%20facebook%20as%20its%20useless/10592897_10203937584333010_2828730942849718897_n.j pg (http://s301.photobucket.com/user/thisYup/media/from%20facebook%20as%20its%20useless/10592897_10203937584333010_2828730942849718897_n.j pg.html)


i'm sure they are in there somewhere, just got to get them out!

:)

[Kaz-kzukNA1]

Looks nice..... Is it SUS304???

Kaz

[mutley]

If that's a piston, I'd hate to see the size of the calliper!

Jim

[britlude]

it's F51 duplex stainless steel, the common name is 2205 (specs- British...1.4462, European...F60, US..F51)

it's a hybrid microstructure of austenitic and ferritic stainless steels (hence the 'duplex' bit), gaining properties from both types!

it seems improved in virtually every aspect to the usual 304 or 316, and has an expansion rate comparable to the cast iron of the caliper!


it sounds like i researched this in depth, but it was more by luck than judgement! :)

[avcrx]

am planning to re-build my brake callipers and most likely needs new cylinders, wondering if you will make an extra set?:rolleyes:

[markc]

i'm sure they are in there somewhere, just got to get them out!

:)

Looks like there are lots of them in that package. Selling on the spares will more than cover it's cost :)

Mark

[britlude]

After removing and stripping the calipers, the problem was obvious…
http://i301.photobucket.com/albums/nn41/thisYup/from%20facebook%20as%20its%20useless/10682291_10203966378852855_22484443861837738_o.jpg (http://s301.photobucket.com/user/thisYup/media/from%20facebook%20as%20its%20useless/10682291_10203966378852855_22484443861837738_o.jpg .html)


Bearing in mind I replaced the seals in the calipers about 5 years ago, and all was well then, as I wouldn’t have put a piston this corroded back in!! In my case it showed itself when I noticed the fluid level had dropped more than expected with normal brake pad wear, hence prompting the brake disc/pad/seals/piston service!


With the help of an evil powered saw, the bar was cut into 55mm billets…. With a spare just in case….
http://i301.photobucket.com/albums/nn41/thisYup/from%20facebook%20as%20its%20useless/10666112_10203965556352293_7156901817744025196_n.j pg (http://s301.photobucket.com/user/thisYup/media/from%20facebook%20as%20its%20useless/10666112_10203965556352293_7156901817744025196_n.j pg.html)


And these were blanked to approximate sizes….
http://i301.photobucket.com/albums/nn41/thisYup/from%20facebook%20as%20its%20useless/10671245_10203965557512322_6037624917340523494_n.j pg (http://s301.photobucket.com/user/thisYup/media/from%20facebook%20as%20its%20useless/10671245_10203965557512322_6037624917340523494_n.j pg.html)


And the lightening holes drilled and sized…
http://i301.photobucket.com/albums/nn41/thisYup/from%20facebook%20as%20its%20useless/10439379_10203965559072361_7444709621298376407_n.j pg (http://s301.photobucket.com/user/thisYup/media/from%20facebook%20as%20its%20useless/10439379_10203965559072361_7444709621298376407_n.j pg.html)

[britlude]

Dust seal location groove cut,
http://i301.photobucket.com/albums/nn41/thisYup/from%20facebook%20as%20its%20useless/10647164_10203965584993009_832923569224956660_n.jp g (http://s301.photobucket.com/user/thisYup/media/from%20facebook%20as%20its%20useless/10647164_10203965584993009_832923569224956660_n.jp g.html)


then they were sized to match the originals and all the edges chamfered and the bases radiused to ease through the seals easier

All 4 completed with the originals…
http://i301.photobucket.com/albums/nn41/thisYup/from%20facebook%20as%20its%20useless/10665113_10203965583632975_5454657125438732980_n.j pg (http://s301.photobucket.com/user/thisYup/media/from%20facebook%20as%20its%20useless/10665113_10203965583632975_5454657125438732980_n.j pg.html)

i gave the pistons a little polish too, just can't help the hot-rodder in me! lol


Sorted!

....the pistons were done while the paint was drying, but that's for another thread!

[goldtop]

Top work! Do you have a CNC lathe in your kitchen? Getting serious tool envy here. ;)

How did you measure the radii and other dimensions? Or are exact replicas not 100% necessary?

[Dragonlady]

I'm guessing he has some vernier calipers in the kitchen drawer!

[mutley]

I'm guessing he has some vernier calipers in the kitchen drawer!

Words like that take me back to my engineering days!

[britlude]

digital vernier calipers.....

and a micrometer!

the only critical dimension is the diameter of the piston and making sure there is a fine surface finish of the piston/seal surface. the corners were 'broken' just to remove the sharp edges and a radius added at the bottom to prevent damage to the brake seal when the caliper is assembled. it's similar in size to the original, but not necessary to be exact!

i sized them to match the OEM pistons that i took out.... the 40mm pistons both measured over, and both the 36mm slightly under!



my lathe is manual with DRO (digital read out)...

.... i made my milling machine CNC!

[goldtop]

Interesting, so it's the seal that does the important bit?

I commission a few turned products for my Web business, but don't have the need to get the sexy machinery.

Yet! :)

[britlude]

the 'similar in size to the original' was refering to the bottom radius size. the diameter/length of the piston on various brake spares sites are listed as 36mm OD x 52 long and 40mm OD x 52 long, where as the originals from my calipers measured 35.95mm and 40.4mm and both 51.3mm long! so even though the originals have 36 and 40 cast into the end, it's more a guide!

the dust shield groove is there to locate the dust cover, so as long as the groove is around 6mm from the end, 3.2mm wide and as deep as the original a small tolerance, say +-0.25mm, is not a problem

the critical one is the diameter, so i made it match the originals, within 0.05mm.

the seal, a square in section slice of rubber tube, does all the work, making the seal to stop the fluid escaping (obviously), letting the piston slide through as the pads are worn down and also retracting the pistons when the pressure is released from the pedal, giving room for the pads to come off the disc.