Caliper rebuild snag

[Zombie Master]

'84 R100
So I'm going through my Brembo calipers. I've got one apart and everything looks good. Cleaned everything up but I can't get the piston to recede past the new seal. So I put in the old seal and no problem. I've tried with just Dot 4, and also with silicone brake grease, and no go. Piston just gets stuck and I blow it out with compressed air. I bought the kits from Motobins and the listing said Brembo. Looking at the listing I see a mention of after market.:

Part No.23300A

CALIPER REPAIR KIT 38mm BREMBO.
(Made from superior EPDM HP compound for the after market)
Consisting of 2 x Dust Seals, 2 x Piston Square Section O Rings and 1 x internal O ring.

FITS :-

FRONT
R80/100/S/CS/RS/RT 1981-84.
R80GS, R80ST 1981 - 1987
R65/80/100 1985-95 ( Twin disc models )
K100/RS/RT/LT ( NOT 16 valve )
K75/C/S/RT

WTF?

[barryh]

The rubber might be superior but the size obviously isn't. How does it compare with the old seal on dimensions ?

If you have to I'd reuse the old seal as they rarely leak unless damaged.

[Ken in Oklahoma]

ZM, this doesn't help you in your situation, I know. But I do want to chime in on non-OEM rubber (and plastic). Simply, I've had too many disappointments from fork bellows that split quickly to parts that almost fit. I don't think I've ever encountered a rubber part that is better than OEM.

I have also developed the practice of laying in spares that I don't need right now (such as ignition coils, carb diaphragms, plug wires, fuel lines etc.)

Right now I live within a half mile from the Boise, ID BMW dealer (Fred Wiley) who has been around for many years. I can get any part a BMW dealer can within a handful of days.

Interestingly I was chatting with him and I happened to ask if he knew Duane Ausherman. He gave me a look and became immediately chatty and even paid attention to what I said. I immediately had been admitted to the 'club'.

http://www.bigtwincycles.com/

Ken

[Zombie Master]

Motobins will issue a refund. I thought these were Brembo parts.

[ME 109]

I rebuilt my 81 calipers recently with Motobins rebuild kit parts, no problems.

[Zombie Master]

I rebuilt my 81 calipers recently with Motobins rebuild kit parts, no problems.

They say they have Brembo parts as well. Maybe they didn't when I ordered. Maybe you got those. I just ordered some OEM from the dealer. I keep learning the same lesson....OEM.

[Zombie Master]

ZM, this doesn't help you in your situation, I know. But I do want to chime in on non-OEM rubber (and plastic). Simply, I've had too many disappointments from fork bellows that split quickly to parts that almost fit. I don't think I've ever encountered a rubber part that is better than OEM.

I have also developed the practice of laying in spares that I don't need right now (such as ignition coils, carb diaphragms, plug wires, fuel lines etc.)

Right now I live within a half mile from the Boise, ID BMW dealer (Fred Wiley) who has been around for many years. I can get any part a BMW dealer can within a handful of days.

Interestingly I was chatting with him and I happened to ask if he knew Duane Ausherman. He gave me a look and became immediately chatty and even paid attention to what I said. I immediately had been admitted to the 'club'.

http://www.bigtwincycles.com/

Ken

I try to keep some spares on hand. I had purchased these caliper re-build kits a while back. I've got new rotors and pads in stock. I have a few years of Mobil 1 15w 50 in stock. Filters, fork boots, drive shaft bolts, gasket kits ect. Sometime shit happens. Sometimes it happens to me. So why haven't we heard much from Duane?

[Steve in Golden]

Yeah, where has Duane been? I hope he is OK.

[Kurt in S.A.]

He's OK. He's working hard to update and add content to his website.

Kurt in S.A.