New R65 Owner- Restoring ATE Brake System

[lebicicletta]

Greetings, R65ers
My 1981 R65 has arrived in Cleveland from Baton Rouge! 26K miles; only 3K since 2003. Hope picture attaches...It hasn't been started/ridden since 2008.
Job one for me is the hydraulic brake system. The reservoir was empty, save for gelatinous goop at the bottom. Brake handle moves with no resistance whatsoever . I've removed and split the twin ATE calipers. Lower brake lines were devoid of fluid...caliper galleries also filled with goop/crud. Pistons appear completely frozen in place; outer seals came out easily, however
So folks.........where from here?  Am assuming I'm looking at a rebuild kit for calipers (best source.....and maybe a source for the square internal washer some refer to?) Also, where to begin/what to do with the master cylinder? My Haynes manual is discouraging, especially regarding the union of the brake hose that screws directly into the master cylinder body.....
Thanks again for your help!  

[Barry]

So folks.........where from here?  

If the system had been capable of producing hydraulic pressure I would always force the pistons out before disassembly. You might still be able to do it with a grease gun through the bleed nipple.

The pistons are likely corroded enough to be scrap and the not so good news is that ATE parts are harder to come by and more expensive than the later Brembo's . Seals and dust seals are available from Motobins and if you do a search of the forum someone did find ATE piston recently.  

[Lucky_Lou]

So folks.........where from here?  

If the system had been capable of producing hydraulic pressure I would always force the pistons out before disassembly. You might still be able to do it with a grease gun through the bleed nipple.

The pistons are likely corroded enough to be scrap and the not so good news is that ATE parts are harder to come by and more expensive than the later Brembo's . Seals and dust seals are available from Motobins and if you do a search of the forum someone did find ATE piston recently.  

I think one of the US members was having the pistons made of stainless steel at a reasonable price................. I would change the master cylinder piston as well which looks like a Brembo from the photo Lou

[Lucky_Lou]

Assuming you have not run the engine up yet there are a couple of things to consider before you get to that....
Gearbox drive splines and the Crown wheel, as its been stood a long time I would pull the rear wheel off and clean and re grease the crown wheel and while its off pull the gearbox to check and re lube the drive splines. Plenty of articles in the tech section to help but if in doubt..................ask
Lou

[DeeG]

You might also be able to force the piston out using an air compressor.  Did that when I re-build the ATE's on an R90/6.  The piston had some rust on it, but no pitting. Was able to use some 0000 steel wool and cleaned it up nicely.

The only problem with removing the piston is that I needed to replace the dust seal, as replacing the piston was pretty much impossible without sliding the dust seal on it first.  I destroyed the first dust seal when I pounded too hard on the plastic block that I used to seat it and the rubber tore just a bit.  As it was just a dust seal, I probably could have let it be, BUT, it wasn't my bike and I didn't want to do that to a paying customer.  So, I bought another seal and tried again.  It is a very tight fit and needs to have equal pressure on the whole thing at the same time, or one portion will slide in perfectly, but getting the other 'side' in is impossible.  And if you try to take it out and do it over, it will probably tear.  

You'll probably have better luck and an easier time on yours, as you have the split brakes.  They early ones are one piece and are a major PITA.

For repair parts, also try Capitalcycle.com  They had ATE parts cheaper than other places.  they also have an eBay store.   (and its Capital with two "a". the proper spelling, Capitol, will get you to a m/c dealer...not the same folks)

Pretty sure this guy is a forum member, and his photos of the ATE rebuild kept my sanity (Thank you, Mr Valenti. The trick with the toothbrush worked great) .  This is the link to the R65 he did:

http://s428.photobucket.com/user/gruntyman66/library/81%20R650%20Restoration?sort=6&page=0

He also has a PDF on this site, somewhere, regarding the O rings on your ATE's.  I did a google search and came up with this:

http://www.bmwr65.org/htdocs/yabbfiles/Attachments/SYNOPSIS_FOR_ATE_r4.pdf

[Tony Smith]

To pop really reluctant pistons out.

You will find that the bore through which the fluid travels between the caliper halves is just the right diameter to tap out to screw in a grease nipple.

I've never met a caliper piston that could resist a grease gun.

[lebicicletta]

yep - grease gun trick worked!

3 of 4 pistons look very good - one my take a little work but appears salvageable IMHO.

[Mike V]

Lon,

Great looking bike!  O-rings will be in the mail tomorrow.

Keep us informed on your work.

-Mike V. / San Diego

[Luca]

I salvaged some pretty rough pistons in my ATE brakes because I was on a budget.  If I had the money or resources, I'd have gone stainless for peace of mind.  Got my rebuild kits from motobins, bux MaxBMW has them too.

I'm pretty sure this guy makes stainless pistons for the ATE calipers at reasonable prices.  www.etypeparts.com  If not, he's certainly capable of making them if he had a spare piston or some dimensions.


I also disassembled and cleaned out my master cylinder with solvent/soap and water and honed it with a small brake cylinder hone... because I was still on a budget.  Not my proudest moment, but it's held up for over 10K miles and some hard use.

Sourced my two lower hoses cheaply from NAPA, though they're a little long and have some extra metal bits in the middle of them.  The upper hose should have a standard banjo fitting at both the MC and the splitter.

[lebicicletta]

Thanks, Luca!
I'd also like to remove the master cylinder and reservoir - the square one, will need to look if it is 15 MM or?

Looks like i can get a rebuild kit for the m/c...good news, I think.

My question is removal. It appears that there are a couple of bolts to extract from below, but the brake line screws in - I haven't removed it yet - will I be able to simply unscrew the m/c from the brakeline (n.b. the reservoir itself is empty, save for some crud in the bottom)?
Thanks, and sorry if these questions seem pesky or elementary.  

[Bob_Roller]

To remove the master cylinder from the handlebar, you need to remove two allen head screws, they are visible if you stand  in front of the bike and look back at the front side of the area .

Then if you are lucky the master cylinder will come out .

If you aren't lucky, you need to remove the brake lever and use a piece of wood and hammer to get the cylinder loose from the corrosion that is usually in there .

I would wait to remove the brake line until you get the master cylinder loosened up, if you have to use a bit of persuasion to get it loose, you won't make a mess with brake fluid coming out of the master cylinder .