linked brakes... what's inside the junction block on the rear

[Cal3Me]

of a G5 junction block or is that all there is,,, just a block with some holes in it ?? How does the balanced compensated part work as stated on the brochure  ?

[jrt]

That's all there is- a Tee to connect master cylinder to two slave cylinders.
There isn't any proportioning (that I can tell). The front and back calipers squeeze the same- it's just that the front stops proportionally better.
Anyhow, I could be wrong, but that's my take on it.

[Chuck in Indiana]

True proportioning valves came in around 79 IIRC. It's hard to peck on this tablet. .

[Cal3Me]

Chuck,,,,,, hurry up in get back in the shop will ya' ...I need you to operate on that J-block and see what's inside and you can't do it laying on your backside

I hope all is going well on your end ... 

all the best,,
Tim & Miriam

[Zoom Zoom]

of a G5 junction block or is that all there is,,, just a block with some holes in it ?? How does the balanced compensated part work as stated on the brochure  ?

It is a proportioning valve. It should have a spring connected to the swing arm. As the swing arm moves, the valve allows more or less pressure to the rear caliper. When working properly, it will allow more bias to the back wheel when a load is on the bike, (more weight over the back wheel). When the bike has less weight over the back, less braking pressure is applied to the rear brake. Idea is to keep it from locking up when the rear has less traction.

Is that what you were looking for?

John Henry

[Dukedesmo]

Don't know if it's the same but the junction/splitter on my LM2 (now removed) has no valve inside, the only part of it that may influence the proportioning is that the rear brake exit is closer to the line in from the master cylinder and of the same large bore, whereas the front brake is connected on the end of the block which has a much narrower bore at that end, a kind of flow restriction?

Whether the extra distance and smaller bore restricts the flow to the front until the pressure increases or not I don't know? Either way mine doesn't anymore because I've de-linked them so I can do the proportioning myself...

[Groover]

The G5 parts manual shows a different part number for the left front brake pads (the left front is the one linked to the rear), and that different part number is a different compound used. The front right and the rear on the other hand share the same part/compound numbers. I believe that's how MG intended the proportioning to work on that model at least. So having the different compound between front and rear on the same pressure line would have different friction rates as a result. At least that's my understanding of it.

[Groover]

The problem is that the original brembo replacement pads are impossible to find, especially that different linked front one, and information on them are nowhere to be found (the grades), So in my searches, I've never been able to cross-reference the grade difference between the linked front and the other two brakes. Most people end up just using the same pads for all three brakes, and that seems to work fine, but to me it defeats the point of that design.

[Triple Jim]

Guzziology has a good section on brake pads and their friction ratings, to allow you to have a chance of finding suitable replacements that perform as Guzzi intended.

[Groover]

^ good tip! I have the latest Guziology, but I never think to look there. Thanks!

[Two Checks]

The spring connection to the swingarm didn't come into use until many years after the G5.

[charlie b]

The T5 has no external connection on the block.  If there is any proportioning it is fixed and internal.

[Stevex]

I've gone de-linked with my LM2. On my bike that block is just a bog standard manifold.

[Arizona Wayne]

I have left my `81 CX100(LM II) linked brake system stock and it has always worked perfect for me no matter the weight distribution from solo or 2up & loaded w/bags & top case.  The few times I need pads I use EBC Kevlar all around.    I wasn't impressed with the original Ferodos.