front brake reservoir diaphragm plate

i'm looking for the diaphragm plate located between the front brake reservoir cover and the diaphragm, too late i found out that mine is missing and there doesn't seem to be any part no. for it.

there was fluid slowly weeping down the reservoir cover and onto the left side of the bracket holding the reservoir, there's a tiny patch about 3 mm wide of blistered paint layer on the bar alongside the bracket, the fluid has moved underneath the bars and onto the top yoke and further down to the chunk of frame beneath where beautiful black paint the size of a big coin has become blistered and started peeling off.

i have washed the affected parts to prevent further damage to the paintwork.

does anyone have a spare diaphragm plate lying about that they're willing to sell me?

Good luck in finding one of them - it could be quite difficult!

If you can find a thin bit of stiff plastic and cut it to the correct shape it might be worth trying to 'make' a new one and give it a try.

dado_dassler wrote:i'm looking for the diaphragm plate located between the front brake reservoir cover and the diaphragm

Hmmm. Try calling Probike at 8622 6296. Bent's little shop has been nominated 'Sparepart supplier of the year' in Denmark and has most things on stock. OE Honda parts, that is. He's a firm believer in quality stuff, meaning there's none of the THansen (Halfrauds) bargains to be had.

I've also got the same problem only that it ran all the way down my mudguard and it's bubbled all of the paint. I'm just going to do a master cylinder/reservoir swap, easier and most likely cheaper than buying parts.

Whenever I've had to rebuilt any part of the brake system, I've replaced the fluid with silicone brake fluid - no more bubbling paint if you spill it or get a leak anywhere.

Is it a Nissin or Brembo master cylinder ??May be able to help with the Brembo one .Dave

eternally_troubled wrote:If you can find a thin bit of stiff plastic and cut it to the correct shape it might be worth trying to 'make' a new one and give it a try.

that will be my last resort, guess i will have to mimic the original one and drill a breathing hole through it too?

stormbringer wrote:Try calling Probike at 8622 6296. Bent's little shop has been nominated 'Sparepart supplier of the year' in Denmark and has most things on stock.

thank you for the link and phone number, i will call him tomorrow.

davecb5002 wrote:Is it a Nissin or Brembo master cylinder ??May be able to help with the Brembo one .Dave  

dave, it's a brembo master cylinder, bike is from 2000.

Alvi wrote:Whenever I've had to rebuilt any part of the brake system, I've replaced the fluid with silicone brake fluid - no more bubbling paint if you spill it or get a leak anywhere.

i never knew such brake fluid existed - any disadvantages?

i have been to four motorcycle shops so far with no luck, one of them told me he would check their supplier and call me tomorrow.

The disadvantage is that a silicon fluid (DOT 5.0) is not suitable for the CB (gaskets may be harmed) and that it may not be mixed with any other fluid. Furthermore, it is not temperature stable, so if the fluid heats up, the pressure point at the lever will travel.

For this reasons, I would strongly recommend the usage of DOT 4 or 5.1 fluid instead of 5.

Regarding the plate: this part is not available as a single item, you have to buy the whole expensive calliper assy to get it. Therefore, you should buy a used part instead.

Flyingbrick wrote:<<>>Regarding the plate: this part is not available as a single item, you have to buy the whole expensive calliper assy to get it. Therefore, you should buy a used part instead.

It's the master cylinder rubber gasket he's after not anything in the caliper. They're still showing available at Lings so I'd have though a main dealer could also source them.

Sorry, I'm not sure about the proper translation.
I was talking about part 9 at http://www.lingshondaparts.com/hpl/images_large/13MY5WEA/imge/F__0400.jpg
Unfortunately, that's the PC26 parts list.
This is the similar picture for the PC32 with Brembo brake:
http://www.lingshondaparts.com/hpl/images_large/13MY5WEA/imge/F__0401.jpg
The part under the top cover and above the (rubber) diaphragm is not sold separately and I guess this is the desired part, isn't it?

Ashcroc, it's plastic plate that sits in between the diaphragm and the master cylinder lid.  It keeps the diaphragm in place and stops it from contorting.  


It's definitely a part that could be 3D printed.  I'll ask my mate who does it as a business if it would be viable (in terms of cost and brake fluid resistance).

dado_dassler, can you send a PM to davecb5002 as he says he's got one.

badseeds wrote:dado_dassler, can you send a PM to davecb5002 as he says he's got one.

ye, i just did, thank you.