Brembo caliper rebuild

[ME 109]

I've been thinking about rebuilding the calipers on my 81 RS.
At 30 years old and lots of heavy use, surely they must need repairing? There doesn't appear to be anything wrong with them, but I'm wondering about one of the fronts blowing out.........at the wrong time.
Brake lines are braided.

A quick search for 'brembo rebuild' gave no results.
I don't mind tearing into things without any knowledge of what I'm doing, but this time I'll ask some questions first.
Such as, are there any special tools required?
Are there better than oe parts to use for a rebuild?

Thanks in advance.

[SteveD]

It's really just splitting the calipers, removing the pistons, inspecting the pistons, cleaning the bore and fluid passages, then reassembly with new seals and the tiny o-ring. No special tools.

Pistons are reusable unless there's evidence of corrosion on them. They might prove difficult to remove, but usually a blast with compressed air will help. When I did mine, the air didn't quite do the job, so I just belted them against a chunk of wood in the direction the piston would fall out. 3-4 whacks doing that and out they came.

Kits are available from Motobins.

[tenni128]

I just did this, pretty easy as Steve pointed out. If you use air, consider a loose wrap of tape, or something to contain the piston. Mine took a fair bit of pressure, then went flying across the shop.
Otherwise pretty basic. That, and it's easier to break loose/re-torque the caliper halves while they are still on the bike.

[ME 109]

Thanks guys.......it's that easy, great.

I haven't heard of anyone blowing a caliper here but it must be a possibility.

I'll send off an order to Motobins.

[tenni128]

Also, they used those calipers on a lot of stuff back then...I saved 5 or 10 bucks by ordering them for a Guzzi Lemans from mg cycle I think. Worth looking around maybe.

[SteveD]

Jeff..check http://www.dropbears.com/s/sda/ in Healesville. They might have the kits.

[DanielMc]

Rebuilding Brembos is satisfying and easy - I split them and remove pistons with a high pressure air line. New seals and "o" ring after a clean then reassemble using a stainless bleed nipple and new stainless bolts to join the caliper halves (no more corrosion!). I never use copper grease when reassembling, preferring instead to give dissimilar metals a light coat of corrosion block grease. If the calipers are looking a bit tatty they benefit from a quick degrease and a spray with rattle-can satin black.

Also, they used those calipers on a lot of stuff back then...I saved 5 or 10 bucks by ordering them for a Guzzi Lemans from mg cycle I think. Worth looking around maybe.

BMW, Guzzi and Ducati used the same P08 caliper so pads, pins, seals and pistons are interchangeable, although caliper bodies are not due to mounting differences between the Italian and German applications. I've never had a piston seize in a BMW Brembo caliper - I think that's because they're all coated alloy. They used to seize in for a pastime when the old chromed steel pistons were used in mid '70s Guzzis and Ducatis. Only cure then was to drill and tap a hole in the centre of the piston, insert a small setscrew and turn it in 'till the piston lifted out....happy days.

Fit braided hose if not done already, and treat the master cylinder to a rebuild while you're at it.

[ME 109]

Thanks again chaps, lot of good information.

Front master cylinder was replaced about 12 months ago. I was a bit pissed to see the new mc leaking fluid, but it stopped leaking. The leak appeared to be from fluid bypassing the rubber seals on the piston, which was why I replaced the original mc ???

I think a new rear mc plus kits for 3 brembos is in order.
Oooh! and some new pads. Ones that don't squeal like the 'metal king?' pads I have at the moment.

[dougie]

+1 what Steved said.
FWIW - my pistons were OK, but there was sludge in the caliper.
Use only brake fluid to clean inside (some alcohol is alright but no mineral spirits, gas, etc.).

[Major Softie]

Yes, rebuilding is very easy, but I've never known anyone to "blow" a caliper. That's one of the great things about hydraulic calipers: catastrophic failure is incredibly rare. On a functioning bike, they will usually just start to leak a bit, or fail to retract - causing the pads to drag, and you know it's time to rebuild.

On a bike that has sat for years, they they are usually just frozen.