Caliper and Master cylinder cross-ref part numbers

[SoloLobo]

My recently acquired R65LS (1982) needs the master cylinder and calipers rebuilt.

Any many of you know, buying the Brembo badged caliper and master cylinder kits from Ducati/Guzzi suppliers is much cheaper than buying from our friendly BMW shops.

For all other Brembo'd BMW's this is an easy chore... seems like there is a knowledge gap on the R65 brembo's.

Can anyone confirm that the R65 Brembo's take the same size pistons as the F08's (or F05's?) if so, the rebuild kits (less pistons) are about $20

I'm also looking to confirm what other makes/models shared the LS's 15mm master cylinder piston, to source a kit elsewhere as well.

Magura made a 15mm kit for some time, but it looks like BMW sued them and sales in the US have stopped

[Tony Smith]

The only way to know for sure what size pistons are in the claipers is to measure them.
 
If you are "lucky" enough to have 36mm pistons, I was only able to find one place that sold seals, they were in the USA and fortunately were more than happy to throw out the 1/2" thick pamphlet of instructions, the new bolts and the tube of rubber grease and just send me the seals in a letter envelope - thus reducing the postage from $US30 to around $US5. Oh, and the seals were so cheap I've forgotten the price and they threw an extra set in because i was so far away.

Any other sized piston seals can be obtained form Bevel Heaven (or elsewhere) very reasonably.

As regards master cylinder kits, nobody seems to sell individual seals anymore, but might be worth a trip to your local brake repairer, otherwise places like motobins sell kits at sort of reasonable prices. A long time ago I bought separate seals to rebuild the under tank master cylinder on my R100 but BMW no longer lists the seals, only kits.

[nhmaf]

I bought a rebuild kit for my 82 R65LS m/c when I first restored it.  It included everything I needed, and something that was missing that I didn't even know was missing at the time.   It worked fine for 4 years or so, but the slight pitting that remained in the bore of the m/c eventually wore the new seal and it started leaking, and I just bought a whole new setup afterward.  Been troublefree now for 5 years.

You can use a smaller diameter m/c setup with those dual discs - some people have gone down to 13mm and like the increased lever travel and more progressive "feel".     I've got the 15mm on my bike and total lever travel from "scrub off a few MPH" to "Stoppie time" seems like only about 12mm... but I am used to it now despite its relative wooden feel it does really stop with fresh organic pads.

[mrclubike]

 What makes Brembo or  ATE R65 calipers different is the piston Diameter
Brembo ATE is 36mm and Brembo F08 is 38mm which makes the rebuild kits not interchangeable
You need to measure yours and if your lucky maybe someone has allready gone to the 38mm calipers
The F08 from a Guzzi has the same mounting as a Brembo or ATE from a R65 and are interchangeable as a complete assy

I installed a Brembo F08 (38mm from a Guzzi) and a 12mm master cyl and a Spiegler line
on my single rotor 82 R65 and it works great
A 2 rotor bike  will use a 15 or 16 mm MC
Motobins has MC in all sizes 12mm to 16mm cheaper than OEM
The pull is firm and very positive feeling not mushy at all
with the original rubber hose the pull was soft but stop very well

This is the caliper I used
http://www.mgcycle.com/index.php?mai...oducts_id=1034
these will work also
http://parts-for-bikes.de/shop/einze...86e76bd4e965d2

 
If you look in the BMW parts list you will see they reduced the diameters of the MC to increase the leverage on the front brake anyway

I was worried it would not  work also
I researched a lot and found all this info and then went ahead and did it
couldn't be happier  
__________________

[jamestnewsonr65]

I rebuilt mine myself with new pistons from here: http://www.etypeparts.com/products/ate15-bmw1
They were pretty reasonable compared to other options and work perfectly. Originals were very pitted, but these are very good.

A couple of rebuild kits, new pistons and a couple of EPDM o-rings and you can have a new set of callipers.

You can see how mine turned out here on page 2: http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1402262450

[Tony Smith]

I rebuilt mine myself with new pistons from here: http://www.etypeparts.com/products/ate15-bmw1

Jeezuz! $107 for four pistons.
 
Turn a suitable length of stock down to correct diameter, polish with crocus, bore out part way, cute dust seal retaining groove and then use parting tool to cut off the first piston. Repeat as many times as the length of stock, need for pistons, or attention span allows.

Around 20 minutes work for a 59 year old lawyer masquerading as a part time machinist to make all four, even faster with a Turret lathe rather than the 4 way tool post I use. And faster yet once the parameters are entered into the CNC lathe they probably use.

Ok, so they are in business to make a profit, but there is profit and profiteering. I would have thought that $25 a pair would give an adequate profit margin.

[jamestnewsonr65]

Unfortunately I don't have a workshop and live in London, so sometimes buying is the only option and easier than trying to resource someone to make them up.

It is easy if you have the knowledge and resources and that's why the info on forums like this is invaluable for people like me who don't necessarily have the knowledge or resources. I'm learning fast though!

The only consolation I have is that they look damn good