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General Category => General Discussion => Topic started by: Moparnut72 on January 16, 2026, 05:05:50 PM

Title: Brake Calipers
Post by: Moparnut72 on January 16, 2026, 05:05:50 PM
The font calipers on the semi basket case T3 I am rebuilding are trash, badly rusted. I think I have found that the '76 Lemans used the same calipers. This came up in AI which I don't trust. It seems that F08 calipers are kind of rare, a few of the ones I have found are in Germany and very expensive and exorbitant shipping and beyond my budget for this disaster. Can any of you guys very that they will fit. I have found a listing for these at a reasonable price. The T3 takes F08 calipers and AI says the Lemans does also. I want to be sure the seller doesn't take returns and these are a bit pricy but not bad. I couldn't find anything in Guzziology about the Lemans. It does say F09 will work though but the master cylinder to caliper ratio isn't very good.  This project that I took on to give me something to do this winter is turning in to be more than I wished for. :angry: If it gets any worse I may park it for awhile. I hope tis all makes sense. Thanks in advance.
kk
Title: Re: Brake Calipers
Post by: 73 sport on January 16, 2026, 05:28:39 PM
     MG Cycle in Wisc. has both left & right FO8 calipers.
Title: Re: Brake Calipers
Post by: Antietam Classic Cycle on January 16, 2026, 05:51:36 PM
All early big-block Guzzis used the same F08 calipers on the front end. The F09 was used on the rear of some 1000SPs. If you can find F08s with the single 10 mm bleeder, those are the best as they usually have anodized alloy pistons instead chrome-plated steel ones. The 10 mm bleeder is also much less likely to twist off.

F08 calipers aren't what I'd call "rare", they were widely used on Guzzis, Ducatis, Laverdas and BMWs. The F09 is sort of rare.

If you're looking at the same ebay calipers as I am, then $250 for a pair that might need to be rebuilt is a bit high IMO. 
Title: Re: Brake Calipers
Post by: yackee on January 16, 2026, 06:07:41 PM
I found that it was worth the money and less hassle to buy new F08s from MGcycle rather than try to rebuild the existing ones. The chrome pistons tend to rust quite a bit if neglected and it can be a hassle to get them out and clean out the existing caliper. But my budget constraint may not be yours. You can use the F08 in the rear, the F09 is hard to obtain. I used an F08 on the rear of my T3, it works great.

You will probably also need to replace the master cylinders, or rebuild them. I rebuilt the front M/C, but still couldn't get pressure, and just bought a new one. The rear is harder to replace.

And the lines themselves--probably worth replacing with stainless-wrapped new lines.
Title: Re: Brake Calipers
Post by: Antietam Classic Cycle on January 16, 2026, 06:28:51 PM
New calipers at MG Cycle: $185 for the right-side/rear (price may not have been updated to reflect the tariff yet) and $266 for the left-side. Both are $200 ea. at Harper's.

The T3 would have had F08s from the factory, only the 1000SP ever had an F09 on the rear.

The front master cylinder is $224 and the rear is $232 at MG Cycle.
Title: Re: Brake Calipers
Post by: n3303j on January 16, 2026, 07:03:43 PM
Brake calipers on the T3 are aluminum and do not rust.

Mine sat for 18 years before I bought bike.

New Teflon coated aluminum pucks are available to replace the rusted chrome plated steel ones.

Split the caliper. Clean the bodies thoroughly. Replace all the rubber bits (including small o ring between two halves) and you will be set for another 100K miles. A lot cheaper than buying new ones.

https://store.bevelheaven.com/Brake-Related-Parts/Brembo-F08-Piston-Seal-Kit-38mm/

The caliper bore only guides the puck. All sealing is done by the square cross section O Ring. As long as the O Ring groove isn't damaged installing a new seal will work excellently.
Title: Re: Brake Calipers
Post by: Moparnut72 on January 17, 2026, 06:44:46 AM
Thanks for all the advice. The pucks are rusted in so solidly I have been unable to remove them. I plan to continue with that. I planned to do that but this road block has me rethinking the project. Spending this much money for just brakes may just put it over the top. I have already purchased forks, carbs, lighting and other misc items and more to go. I will also have to rewire the whole bike. The previous owner(s) went through it with wire cutters. I also have a parts frame which I picked up later and thought I could recover some bits that were missing but no such luck. I am not a quitter so I will push through but probably on a delayed schedule and just ride my V7.
kk
Title: Re: Brake Calipers
Post by: n3303j on January 17, 2026, 07:49:58 AM
Pressurize the caliper half with a grease gun. That should drive the piston out. Numerous people have shown ways to install a grease fitting in one of the ports.
Title: Re: Brake Calipers
Post by: Moparnut72 on January 17, 2026, 08:42:54 AM
Thanks, I will give that a try. I was thinking something along those lines but this is a better idea.
kk