Grimeca Brake Calipers -Semi Guzzi Content

[SIR REAL ED]

Subject matter is the front brake caliper from a MZ Skorpion.  Made by Grimeca.

Self appointed MZ experts say "Grimeca brake components are junk and should be replaced with Brembo components."

Some people say "Some Moto Guzzi models used Grimeca brake components."

I have been told that some Grimeca brake components are dimensionally identical to some Brembo components.  Brembo makes a P4 30/34 caliper that many riders use to replace the Grimeca caliper on the MZ.  The Brembo piston diameters are 30mm and 34mm.  Interestingly, the Grimeca piston diameters are 30mm and 35mm.

I'm told the Grimeca pistons are made from sintered metal which has a higher coefficient of thermal expansion than the cast caliper housing.  The pistons may be prone to seizing when hot.

My front brake did seize up.  Luckily, it occurred relatively slowly over the course of 20 seconds or so, and I figured it out quick enough to get out of traffic.  I just assumed it was due to the previous owner overfilling the master cylinder.

So my questions to the WG flock are:

1.  Have you owned any bikes with Grimeca brakes?  Is so, what year, make, and model?
2.  Have the Grimeca brakes on that bike(s) caused you any problems?
3.  What did you do to resolve the problems?
4.  Any suggestions on where to buy piston seals and dust guards for Grimeca brakes?

Thanks in advance!

[circlip]

The later Moto Morinis had Grimeca disc brakes.
1980 Morini 500
1986 and 1987 Morini Camel
1987 (?) 350 K2
I wish I had kept at least one. I never experienced any brake issues.

I also had a MZ Skorpion, but no brake issues there either.

So, I'm really no help to you.
My impression was that Grimeca brakes were fine. My experiences were good.
Apparently they make bicycle brakes, but I'm not seeing much else on the internet.

[nc43bsa]

I roadraced a Skorpion for three years with the OEM Grimeca brakes (aside from the hoses & pads) and never had a bit of problem.

I did flush the fluid yearly.

[Antietam Classic Cycle]

I don't know of any Guzzi that used Grimeca brakes - maybe some of the small models that the US never got?

Are you sure the bleed hole in your master cylinder isn't blocked and not allowing fluid to return? Classics symptoms of that.

To answer your questions:
1. Morini 500, 350 K2 (2), 3 1/2 Strada, MZ Saxon Country 500 and Silver Star Classic 500
2. None other than age related (leaky seals)
3. Bought a rebuild kit (Ariete kit for the second 350 K2 master cylinder)
4. Storz Performance used to be a source for parts, but that seems to have ended. Some Brembo parts fit, on some calipers. My friend Jarl needed seals and pistons for the 38 mm calipers from his 500 Strada - F08 seals and pistons fit perfectly. Google Ariete - they're an Italian company that makes rubber bits, "valtermotousa" on ebay sells a lot of their stuff.

[SIR REAL ED]

I roadraced a Skorpion for three years with the OEM Grimeca brakes (aside from the hoses & pads) and never had a bit of problem.

I did flush the fluid yearly.

Annual flushing of brake fluid is an excellent practice.  I do the same, and I've never had a problem with a bike that I have owned.

The MZ was the first bike I have ever taken for a ride before I went thru the bike and made sure everything was up to snuff.  That will never happen again.

The previous owner told me he recently did extensive maintenance of the bike (including changing the brake fluid, it did look new) and took the bike out for 50 miles to verify all was OK.

In less than 3 miles, the front brake took on a mind of it's own...... live and learn.

[SIR REAL ED]

I don't know of any Guzzi that used Grimeca brakes - maybe some of the small models that the US never got?

Are you sure the bleed hole in your master cylinder isn't blocked and not allowing fluid to return? Classics symptoms of that.

To answer your questions:
1. Morini 500, 350 K2 (2), 3 1/2 Strada, MZ Saxon Country 500 and Silver Star Classic 500
2. None other than age related (leaky seals)
3. Bought a rebuild kit (Ariete kit for the second 350 K2 master cylinder)
4. Storz Performance used to be a source for parts, but that seems to have ended. Some Brembo parts fit, on some calipers. My friend Jarl needed seals and pistons for the 38 mm calipers from his 500 Strada - F08 seals and pistons fit perfectly. Google Ariete - they're an Italian company that makes rubber bits, "valtermotousa" on ebay sells a lot of their stuff.

After loosening the bleeder and squeezing out "3 lever pulls" of fluid, I was headed home.  Slowly and very attentively!!!

A blocked bleed port was my second thought Charlie.  When I got the bike home, everything checked out fine.  Other than the seals being cooked enough to not hold a solid bleed for more than a day or so.

So far my searching has not been very productive.  Of course with room for infinite information on the internet, very few vendors provide dimensional information.

I'll have to measure the seals and dust guards, and consult the industrial suppliers.  OD's and ID's look the same for both, but the dust guards look half as thick as the seals.

[Roebling3]

I put a Grimeca 4LS front, (plus a rear 2 shoe), a friend rebuilt for me.  18" front 17" rear rim, spokes, shoes et. al. Looks brand new.
Nicely modulated Stoppies, from ~35mph. Just sayin'. Wish I could still kick that beast through. 500cc, 2 stroke, twin.  R3~

[SIR REAL ED]

I put a Grimeca 4LS front, (plus a rear 2 shoe), a friend rebuilt for me.  18" front 17" rear rim, spokes, shoes et. al. Looks brand new.
Nicely modulated Stoppies, from ~35mph. Just sayin'. Wish I could still kick that beast through. 500cc, 2 stroke, twin.  R3~

Suzuki GT 500?

[Chuck in Indiana]

I have Grimeca brakes on the Skorpion. They've been fine, although I modded them to take Guzzi HH pads for a little more stoppage.

[Turin]

I've never heard of a guzzi with grimeca brakes either.

I've never heard anything bad about Grimeca brakes, only that Brembo is supposed to be better.

I wouldn't mind giving them a shot.

[Roebling3]

Nock, nock: Correct. Sir Real.

It began as a race bike. The guy building it road raced various 2 strokes. He wanted bigger & better but got worse instead, Wrong frame choice. Wrong fork, poor wheels, yada - - - - . It's for sale. I have a new pair of polished stainless HiggsSpeed tuned exhaust, plus a NOS GT frame & swing arm. Pictures available.  Good fortune,  R3~

[jacksonracingcomau]

Ok, here’s a Guzzi with Grimmies, my 1967 V700
Not standard you say, true indeed but the entire front end came from a production Guzzi Nevada, exact year and production number I don’t know, I was given it in England and bought the lot (less rim and spokes) in my luggage back to oz.
Was odd mix, Brembo master cylinder and floating discs, Grimeca calipers that look like 05 Brembos and take same pads.
Other oddities on this model are 38mm forks with trailing axle similar to Lario 35mm forks so possibly similar year, 88 ish ?

I bought 05 seal kits thinking they had to fit, the dust seals did but not the piston seals, width of seal is very different.

Grimeca were, of course, the big name in drum brakes but relatively rare to see their disc calipers, why the Nevada had them is outside of my knowledge, but I have a Lario with 05’s and the same master cylinder, doubt I could tell them apart by feel although the 8v is running bigger floaters and is half the weight so it does stop quicker.
Neither ever fade nor boil.

Whenever I’ve seen overheating front brakes it’s been a master cylinder issue, notably usually adjustment, some Brembo masters allow you to completely remove free play and lightly load the piston, a couple of laps into race and things get hot quickly. Exactly the same result as blocked passage or old rubber lines disintegrating internally.
Rear brakes getting hot can be same cause but much more likely to be the nut behind the handlebars .

[huub]

I have grimeca calipers on most of my morini's, pretty similar to brembo stuff.
the last ones i rebuilt with home made stainless piistons and EPDM x-rings as seals  because rebuild kits were hard to find ( a 1977 bike)
if you are running the rubber brake hoses , check those.
I had several break down internally , causing the brake to bind up.
you could pump fluid to the caliper , but it rould not bleed back.

[Chuck in Indiana]

I have grimeca calipers on most of my morini's, pretty similar to brembo stuff.
the last ones i rebuilt with home made stainless piistons and EPDM x-rings as seals  because rebuild kits were hard to find ( a 1977 bike)
if you are running the rubber brake hoses , check those.
I had several break down internally , causing the brake to bind up.
you could pump fluid to the caliper , but it rould not bleed back.

Good stuff..

[SIR REAL ED]

I have grimeca calipers on most of my morini's, pretty similar to brembo stuff.
the last ones i rebuilt with home made stainless piistons and EPDM x-rings as seals  because rebuild kits were hard to find ( a 1977 bike)
if you are running the rubber brake hoses , check those.
I had several break down internally , causing the brake to bind up.
you could pump fluid to the caliper , but it rould not bleed back.

I agree with all of that!   

EPDM X-rings are the next item in the search list.

Other than a couple MZ riders badmouthing Grimeca, most seem pleased with them.  As always, a few complaints generate more noise than dozens or hundreds of satisfied riders.

Then again, the Ninja 400 front end I have will slide right into the MZ triple clamps.  Lighter weight, better looking, newer tire and complete front brake system.  Only step down is a two piston caliper instead of a four piston caliper.  I know the rear wheel is an easy swap... just to keep it looking reasonable.

Not sure there is much of a market for MZ components.  Selling components is good for freeing up garage space....

[Chuck in Indiana]

Not sure there is much of a market for MZ components.  Selling components is good for freeing up garage space....

As nearly as I can tell.. slim and none. Pick one.  Guzzi buddy Kevin in L.A. *gave* me a complete skorpion less engine..

[SIR REAL ED]

Nock, nock: Correct. Sir Real.

It began as a race bike. The guy building it road raced various 2 strokes. He wanted bigger & better but got worse instead, Wrong frame choice. Wrong fork, poor wheels, yada - - - - . It's for sale. I have a new pair of polished stainless HiggsSpeed tuned exhaust, plus a NOS GT frame & swing arm. Pictures available.  Good fortune,  R3~

I for one would like to see pictures.  If you don't want to post them, please send them to me in a private message.

[SIR REAL ED]

As nearly as I can tell.. slim and none. Pick one.  Guzzi buddy Kevin in L.A. *gave* me a complete skorpion less engine..

I agree.  Most people have never seen one and have no idea who makes them.

Anytime you find one, it is priced very low.  Good project bikes for cheap hacks like me!  If it gets screwed up, you don't lose much money!   

A friend in Canada who recently sold the Moto Guzzi 350 Adventure bike that I posted pictures of here, has an MZ Skorpion, and he figures it is the only one in Canada.  Who knows, he may be right.