Scott560's & Vtecmec's info on new brake Master Cylinder's

[Drax]

I looked into this extensively and wrote about it. I don't think you can get them from anywhere.

I found a few listings, but these were for LHD cars, but some sneaky websites flipped the image, so I don't think any aftermarket ones are available.

The new one is not available from honda anymore. The 2 pistons are 80quid each from the UK. I recently purchased mine from amayama and they were only about 22quid each. I haven't yet rebuilt it but this was the only option.

Looking at accord type R, nothing seems to match in terms of fitment/interface with the servo or the brake pipe outlets didn't match up.

If you find something do let us know.

This is what i ordered in the end:

Honda 57520-SD4-023 - PISTON ASSY., PRIMARY
1 28.29
Honda 57540-SD4-023 - PISTON ASSY., SECONDARY
1 28.29
Honda 57560-S04-J51 - GUIDE ASSY., PISTON
1 9.63

Arrived on the 8th day after having ordered, pretty quick.

[Drax]

https://www.amayama.com/en/part/honda/57520sd4023
https://www.amayama.com/en/part/honda/57540sd4023
https://www.amayama.com/en/part/honda/57560s04j51

Rebuilt the spare master cylinder today, and can confirm the 3 part numbers I've listed above are pretty much all you need. You can splash out on the grommets and new circlip if you really want to but I don't think they are needed.

General tip - keep all your parts that you take off laid out neatly and in their original orientation. It's probably impossible to put it together wrong, but it never hurts to have a reference.

Useless without pictures, but the process was:

Disassembly:

1) empty then unscrew fluid reservoir retaining screw at its base and pry it off, remember the orientation (lid bit towards the front of the car)
2) retrieve 2 sealing grommets, careful not to scratch anything. Notice that the inlet closest to the front of the car has a metal pin in it.
3) Internally, the second piston assembly is held captive by that metal retaining pin. Depress the big silver shaft 5mm or so, and then tip the whole thing upside down. The metal bar should fall out by gravity alone.
4) wear eye protection - remove the internal circlip with circlip pliers from the shaft end. Don't loose it or let it ping off.
5) pull out the shaft, piston guide, the primary piston will come out with it.
6) A little bit of tapping, the second piston set should fall out also (as long as you have removed that metal pin, had me stumped for a while, the manual mentions nothing of rebuilding the MC, only replacing it entirely!)

Cleaning:
1) prepare a clean place, layout a towel etc, get a load of brake clean (nothing like carb clean etc), and some fresh new brake fluid (dot 4). Wear gloves naturally.
2) clean everything that is old and to be reused - you do not want any grit/cloth/dirt getting into your pistons/cylinder. I used brake clean for the cylinder and liquid lighter fluid for the reservoir.
3) Pour a little brake fluid into the cylinder, lube it all around.
4) I took some time to wash out the reservoir, filter screen and the cap/seal.

Reassembly:
1) take the second piston assembly (the one sits deepest in the cylinder), dip it into the fresh brake fluid so its submerged, and then put it in all the way home into the bottom of the cylinder. Be sure to get the orientation right. You want the 'slot' in the piston to be facing upwards so that the metal dowel can drop down and through it.
2) find something long, hard, but not sharp (like a wooden dowel), depress the second piston assembly inside the cylinder , and then drop in the metal pin in the top. The secondary piston should now be held captive at the bottom of the cylinder. Check that the pin has fallen all the way in. It should almost flush with the inlet.
3) submerge the primary piston in brake fluid, Insert the primary piston into the cylinder.
4) push the piston guide over the shaft, checking that there are no sharp edges on the primary pistons shaft that could damage the seal. The original had a little grease applied but i did not put any on for risk of contamination with the fluid/seals in the future.
5) depress the shaft (and the piston guide) a little, and reinstall the internal circlip
6) reinstall the reservoir noting the correct orientation, cap end towards the front of the car.

I then filled it up and left it for a while, it took a while for it to purge itself of air and fluid start dripping from the outlets - I suspect bleeding it will be a pain...

[Vtecmec]

Found this 4th gen guide with great pictures on the interwebs.

http://www.ozhonda.com/forum/showthread ... er-rebuild

[Vtecmec]

On a 4th Gen, the stopper is a different part, but the rest is the same.