how best to clean cruddy front brake seals (which are now out of stock)

Based on this thread:
kzrider.com/forum/5-chassis/607445-1976-...brake-caliper-issues
...it sounds like the front brake seals have been out of stock for quite a while.
CMNSL is not letting me add them to the cart either.
The ones I have are not torn, just cruddy, especially on the back side where they meet the cast body.
I was thinking I could try to clean them up, but am unsure how. Maybe ultrasonic cleaning in distilled water (or water + Simple Green for 5 minutes, then rinse thoroughly and blow with compressed air?). I could also try to massage the back side of the rubber against scotchbrite (not the side that faces the piston, which is in better shape).

I've never rebuilt brakes where I couldn't just replace the seals.

If the seals are knackered, I would reckon thats it. For safety reasons. If you do manage to clean them up,theyre going to need replaced at some point anyway. You might as well sort it now.You could try www.z-power.co.uk/ for all things Z-ish, or www.powerhouse.uk/content/motorcycle-bra...caliper-services.php for all things brake-ish.
If they cant help,maybe its time to upgrade your calipers. Fit something more modern,or something from a more common/popular bike from the same era.
Good luck with it

You should be able to use your fingernail and scrape off any crud on the seal. If that method fails I'd search out a new seal. There is one on ebay but it seems overpriced.

You should be able to soak them in clean brake fluid, and carefully pick the crud off with your fingers. I would not use anything abrasive on old, brittle seals.
Like the other posters, I would be very reluctant to use old seals. Your life depends on them not failing.

I've never used the stuff, but maybe consider getting some Red Rubber Grease to clean the seals. I don't think that's one of its intended uses, but since it's a rubber lubricant, it might help to rejuvenate the seals.


ps: It helps to mention what motorcycle you have. also, parts numbers.
...

maybe its time to upgrade your calipers. Fit something more modern,or something from a more common/popular bike from the same era.

I was just thinking about that. I saw the thread on replacing with KZ440 fork at
kzrider.com/forum/5-chassis/597812-kz400...r-fork-swap-tutorial

My first bike was a GS500, and that thing was largely unchanged for 24 years (1988 to 2012). Getting parts was so easy.

ps: It helps to mention what motorcycle you have. also, parts numbers.

regarding my model/year, I actually wasn't sure until today, since the bike had at least the engine swapped. But it sounds like the frame is 1977 KZ400-D4, so I'd expect the brakes to match that. My brakes have simple inner & outer seals; no dust cover, no slider pins. It looks like the seals are
43049-004 RING,PISTON SEAL and 43083-002 SEAL.

It looks like CMNL has 43049003 for 4 Euros ($35.11 USD after shipping). There's also someone on eBay in Provo UT selling that for $46.

FYI, I ultrasonic-cleaned the old seals with Dawn; then used a fingernail. There was much more mess in the grooves for the two flat seals, which I cleaned with a pick and steel wool. After cleaning the grooves out, I was able to get the seals and piston back in OK. The seals have been holding well (no leaks; piston retracts OK).

However, these brakes are missing a pair of clips on the caliper side: it's '77 KZ400-D4, and it's supposed to have:
- caliper
- shim (which I've got)
- two opposing clips #9 on drawing below (#43084-002 which I'm missing)
- pad



I'm presently looking for 43084-002 clips.

Another question is: is there a KZxxx brake which will bolt-on to a '77 D4, where rebuild kits are still available? When I search eBay for "kz400 brake set", there are kits with a flat seal, a dust seal and slide-pin boots... it looks like those match the 1980-ish KZ400s.

SpecialGreen wrote:
I'm presently looking for 43084-002 clips.

In my opinion those so called shims (CMSNL) are not nessasary and a waste of time to searching for.
Get the Piston seals and dust seal and you are ready to go for your caliper rebuild.

I cleaned and reused mine but they eventually leaked again and ruined the pads. I have the eBay ones and they are working great. I talked with the seller quite a bit before and after. He's a good dude who is happy he can help keep these old bikes on the road. Before he came along there were no other alternatives.