Replacement/Upgrade Calipers

[jimhutcheon]

Hi,
This is my 1st post as I've acquired a project R65 which is coming along, apart from the  twin front ATE calipers, which are both seized, and proving impossible to remove the pistons from.  
I have heard that it may be possible to replace/upgrade the calipers with certain others, i.e. twin pot brembos, or  calipers from another bike completely.  Has anyone any ideas or info on on this?
Thanks in advance for any replies.
Jim

[Bob_Roller]

The Brembo calipers on the LS version R65 will bolt right on, if you can find a set .

[montmil]

The Brembo calipers on the LS version R65 will bolt right on, if you can find a set .

Begin searching the Euro eBay. They are out there.

And welcome to the herd. Post up a snap of your scooter cuz we love photos of member bikes.

[Julio A.]

You can bolt on a four pot caliper from early R1100's with slight modifications. You have to remove the threading in the caliper as well as milling 4mm or so from the tabs. After that, they bolt right up.

If you can't find LS specific calipers on ebay, try searching for Brembo F08 Calipers, aside from differences with regard to threaded and non-threaded holes, their offset and spacing are all the same.

[John M]

i don't think the oilhead calipers will fit the earlier ate forks. I did this conversion on my 1986 r65 which originally had the later 2 pot brembo calipers (a significant improvement in braking force and much better feel resulted ) for the later airheads it is an easy swap with only the removal of a small amount of aluminum from the mounting lugs of the caliper to properly center the caliper over the disc.

[tvrla]

Julio - I think you're referring to the monoshock bikes from '86. The earlier ones (79 - 84) with the ATE and Brembos are different.

I seem to recall going through this before and finding out the four pots wouldn't work on my 83.

The early R65s have a unique caliper that interchanges with no others.

I believe Motobins or one of the shops in GB sells stainless pistons for ATEs and Brembos. So don't give up on them just yet! Pistons can be difficult to remove even when they're undamaged, so let us know what you've attempted to this point.

I've found using a grease gun to pump the calipers full to be the most controllable way of removing pistons, especially when compressed air just doesn't do it. A grease nipple will screw in part away - enough to make this alternative work.

[Barry]

Are the pistons so seized that if you remove the pads they won't budge under hydraulic pressure from the brake system ?

As wirespokes said the pistons can be hard enough to get out at the best of times. I always pump them most of the way out before draining the brake fluid. Potentially messy but it's the quickest way if you don't have compressed air.

[jimhutcheon]

Thanks for all the prompt replies. Wirespokes, I'll try the grease gun next.  Have tried compressed air, and refitting/refilling with fluid, but to no avail. Next I had thought of having a bolt welded to the piston, may be drastic, but they're not working anyway. Hey ho.

[jimhutcheon]

Its a '79 UK model by the way. I'll post pics when I work out how, and it doesn't look quite such a shed.  

[Julio A.]

Julio - I think you're referring to the monoshock bikes from '86. The earlier ones (79 - 84) with the ATE and Brembos are different.

Sorry, but I really beg to differ.
I have tried Three different Calipers on my R65, all of which connected straight up with no modifications on my 81'

The First one is the Original ATE Caliper
The Second one is a rear F08 caliper from an R100
The Third is a Four-pot Caliper from an R1150 RT.

They all have the same mounts, except for the Four-pot which had threads on the holes, I had to drill them out to bolt them on as well as the offset was different, But modifiable. Nonetheless, they easily bolted on.

This may be the reason why I am having a discrepancy with regard to piston sizes. The original F08's should have 38mm pistons whereas the Brembo F08 caliper I am using right now has a 36mm piston; the same as the R65's original ATE caliper.

By any chance, do you know what piston size the original Brembos on the LS have?

Here's a detailed comparison between the R65 Specific ATE and the rear F08 from the R100. http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1311933847

[tvrla]

Thanks for that Julio! I appreciate your taking the time to document your findings!

Did you ride with the 1150 RT calipers? I'm curious how they worked. What size master did you use, and would you recommend it?

My dual two piston brembo LS front brakes seem to be plenty sufficient so don't think I'd need anything more. But a single disc system with an 1150 four pot caliper might be an interesting way to go. I've been wanting to build an R65 Scrambler, so that could be a possibility. Two four-pots seem like over-kill.

[steve hawkins]

I change my ATE's for Brembo's on my 1979 R65 Cafe Racer.  It was cheaper to do this than rebuild the ATE's at the time.  I got second hand Brembo's (those fitted to later model twin shock bikes) from Motorworks.  

The only fly in the ointment is that the piston size of the ATE and Brembos calipers are different.  So you should change the Master cylinder as well.  They do work without changing the Master cylinder, but they are quite wooden and lack feel.

Changing the master cylinder will lead to other mods - like wiring for brake light switch - which is different, etc.

Cheers

[jimhutcheon]

Many thanks to all who have taken the time to reply and post info on this. Wieespokes, the grease gun works like magic! One piston to go, but both calipers are currently soaking in a bucket of gunk, and I'm sure the last one will pop out. 11 years in a wooden shed doesn't do a bike any favours!

[tvrla]

Excellent! Glad to hear it!

So how's that one look that you've removed?

Another trick is to soak rusty iron in white vinegar. Gets rid of rust like magic! Soak the axle and special nuts then paint them with Chrome paint and wipe off. Where it's left will be protected from rusting and look pretty decent. I use Krylon Dull Aluminum for places I want a look just like Cadmium plating.

[John M]

my 1986 monoshock with 1999 r1100 4pot calipers works very well, it gives me about 50% more swept area . The master cylinder is14mm
on my bike and the power of the brake is  much better ,also the feel is better . The original 2 pot brembo with fresh pads properly broken in had a wooden feel and could not be modulated nearly as well as the 4 pot caliper . I have  approximately 2000 miles on the 4 pot conversion and it is a very inexpensive improvement . My out of pocket cost is about $75 for the used caliper and new pads to go with it