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Gas Gas Formula Brakes - Sherco To The Rescue! (2013 Upgrades)


jonny042
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Hello all,

Just thought I’d share with everyone who cares, the continuing saga of my 2012 Gas Gas with the Formula brakes. I detailed some of my issues with these brakes here:

http://www.trialscen...s-fiasco-fixed/

Although I was able to solve a few things as I documented in that thread, there are still a few issues with these brakes that keep them from being great.

The first and foremost thing is the side loading of the master cylinder piston when you pull the lever. When everything is clean and lubed and flushed this doesn’t present much of a problem, but stuff the levers in the dirt a few times, or get too many hours on them without flushing them, and the feel at the lever goes off in a big way. If you manage to get them dirty enough, when you apply the brakes hard enough, they will actually stick then let go, and make cracking sort of noises! Not really what you want in a brake setup.

So as I was waiting for the long, cold, Canadian winter to come to an end, aimlessly surfing the net, I stumble across the fact that Formula has upgraded the brakes as installed on the 2013 Sherco. Here is a quote from their marketing info:

“The ST2013 models are equipped with the new Formula brake kit that is the result of a joint effort by the technical departments of both Sherco and Formula.

The result is a new unit that includes new internal parts, piston, rod and ball joint (link) that have been perfected to permit smooth movement of the lever in any position, maintaining the pressure and force necessary for effective brake operation. This new set is the most advanced and evolved ever to be installed on a trials bike, it also incorporates an adjustable neutral position that allows the rider to adjust the lever position to suit their individual requirements. The actual lever has an ergonomic geometry that fits perfectly in your hand.”

Apparently Josep Paxau had a hand in the re-design of the brake/clutch master cylinders, and I noticed at Sheffield Albert Cabestany was using the Formula Brake (but looked to be using an AJP Clutch). Pictures on the Sherco website showed the changes to the units, so I started to become interested in this…..

Fingers crossed, I went and downloaded the parts manuals from the Sherco website, and sure enough there they were, parts with the designation “13”. Then I checked the 2012 Manual and Sherco is offerring an uprade kit! This encouraged me, knowing that the upgrades would be “bolt-on”.

With the help of Ryan Young (very helpful as always) and my all time favorite Trials Supplier Stuart Preston at Jack’s Cycles, I was able to determine that yes, these parts exist, and are in stock and available.

So, the Sherco parts required to upgrade a Gas Gas are:

(x2) 4647 – Lever complete 13

(x2) 4649 – Bolt

(x1) 4652 – 9.5mm kit (for clutch) NOT MINERAL OIL COMPATIBLE, USE SILICONE DOT5 Fluid)

(x1) 4648 – 10mm kit

These are all 2013 Sherco parts. The 2012 Sherco used (I think) a 9mm clutch M/C and a 9.5mm Brake, so the parts required for those are slightly different (but available). The complete setup will be in the neighborhood of $225.00(US).

So I went ahead and ordered these parts from Stu, they were drop shipped by Ryan and I had them in a few days.

I am really pleased with what I see. They have fixed every design flaw that I uncovered last season:

- The side loading imparted on the piston by the lever “sliding” on the end of the piston, causing erratic feel: the new unit has an additional linkage and plunger which transfers force far down to the exact geometric middle of the piston so it will not cock in the bore even when there is side loading, much reduced as well by this configuration.

- Brake fluid becoming dirty and contaminated within a few hours: the new design (see above) will reduce side loading and friction, but also the new pistons are coated unlike the raw aluminum of the old parts.

- Scoring of the master cylinder bodies (mine are) - The new design should eliminate this possibility. (I’ve ordered a 10mm and 9.5mm flex-hone to polish mine up).

- The thumbwheel adjuster becoming “unclocked” from the detent it is supposed to line up with, resulting in an instantaneous change to the biting point (not good at any time much less when you’re in a section!): The thumbwheel now has a spring and ball detent arrangement, very ingenious, and allows ¼ turn adjustment to the neutral lever position as opposed to the ½ turn resolution of the previous setup.

- Retractable lever, retracting, when it shouldn’t – the return spring on the old setup was far too weak, and very occasionally, when you went to put your finger on it, it was not there. – the new unit has a stiffer spring.

- Too much play between lever and plunger – although not terrible, there was in my opinion just slightly too much clearance here causing play in the lever – the new units have adjustment so this can be dialled completely.

- O-ring on brake side swollen – I’ve been noticing the brake would often be a bit sticky after the bike sat for a few days. Would usually remedy itself after a few applications but was surprised to find that the O-ring on the brake master was swollen to nearly twice its original size. As a precaution I am going to clean out and flush both the clutch and brake sides with dot 5 and use it, just to avoid this possibility in the future. This will also ensure compatibility with the “mineral oil only” Gas Gas clutch since I think Sherco uses Brake fluid in the clutch.

- Ridiculous pricing on spares via Gas Gas - I paid $55.00 for a spare lever (just the blade!!) from Gas Gas UK. (the US parts importer did not seem interested in selling me one but the most recent price I heard for a lever from another well known parts supplier in the US was $85.00. I don't know what they are smoking in the mountains of Northern California but it must be expensive). If you buy a 2013 style lever from a Sherco supplier you shouldn't expect to pay more than $49.00 - and this will include the entire lever assembly, actually 8 parts in one.

So now on to a few pictures....

post-9272-0-76307700-1360772152_thumb.jpg

post-9272-0-84002100-1360772206_thumb.jpg

post-9272-0-26441200-1360772243_thumb.jpg

post-9272-0-52038700-1360772297_thumb.jpg

I’ve had a chance to confirm that the parts will fit in the 2012 master cylinder bodies, and from an engineering standpoint are a huge improvement over the old stuff. Of course it will be a few months before I can test them myself, but hopefully someone can provide some feedback before then – I have heard a few comments that the 2013 Brakes on the Sherco’s are a big improvement over the previous year, so these updates should make a similar improvement to the 2012 Gasser. In fact, I would agree with the Sherco marketing claim that these are the most advanced brakes ever fitted to a Trials bike – they certainly are!! The new parts are very nicely done.

Many thanks to Stu at Jack's Cycle for working with me on this - he is a dealer for Beta, Sherco, and Gas Gas, so has access to these parts and I'm sure would help in any way possible.

Cheers, Jon N.

Edited by jonny042
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Great post!!!! Thank you! Heard anything on the rear?

The rear brake seems comparable between my '11 and '12 bikes, although like many I had trouble with the rear M/C seals going after a few days of riding. I am planning to disassemble the rear completely to inspect, clean, and hone the Master Cylinder bore.

Functionally speaking I don't think there is any difference between the AJP caliper and the formula caliper on the rear.

Also of note is the availability of the Jitsie "Race" Brake pads - I've ordered a set for both my bikes, as I am fairly certain through all my horsing around I managed to contaminate the pads, and I have heard that they are a good upgrade to the originals - we shall see... and I will report my findings.

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Great post, I have to agree that the new design lever and piston is much better, these brakes are really powerful.

We keep these parts in stock if anyone wants them:

2013 style complete lever

2013 lever bolt

2013 style piston kit - 10mm

2013 style piston kit - 9.5mm (on order hopefully here soon)

2013 style piston kit - 9mm

The other option is to just swap back to the trusty AJP master cylinders, they use the same thread as the Formula brakes but sometimes the end of the pipe burs over slightly and requires filing down slightly so you can thread them back on.

Cheers

Chris Pearson

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Functionally speaking I don't think there is any difference between the AJP caliper and the formula caliper on the rear.

I think you will have to swap the disc side wheel spacer, well you do on the Sherco anyway, the Sherco wheel spacer with the Formula brakes is 2.25mm wider.

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The 2012 Sherco used (I think) a 9mm clutch M/C and a 9.5mm Brake The 2013 Sherco front brake uses a 10mm piston, not sure about the 2012

As a precaution I am going to clean out and flush both the clutch and brake sides with dot 5 and use it, just to avoid this possibility in the future. This will also ensure compatibility with the “mineral oil only” Gas Gas clutch since I think Sherco uses Brake fluid in the clutch.

As a word of caution Dot 5 brake Fluid is Silicon based it dosen't mix with either Dot 4 (Glycol based) or Mineral oil and I've no idea if the rubber seals on the piston or your slave cylinder are compatible with it, I guess you'll just have to try it on one of your old seal kits. If you do swap it make sure to flush all the old oil out by disassembling and cleaning all parts with isopropyl alcohol.

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As a word of caution Dot 5 brake Fluid is Silicon based it dosen't mix with either Dot 4 (Glycol based) or Mineral oil and I've no idea if the rubber seals on the piston or your slave cylinder are compatible with it, I guess you'll just have to try it on one of your old seal kits. If you do swap it make sure to flush all the old oil out by disassembling and cleaning all parts with isopropyl alcohol.

Hi Chris, Thanks for your replies!

As far as I can tell the Silicone Fluid should be compatible with any and all seals, o-rings, etc., if they were originally mineral oil compatible or not, so that's my "safe" option. But no doubt will require a thorough cleaning beforehand, as I have heard some stories about sludge buildup, etc.

The other option, I suppose, is to find out if the formula seals in the new kit for the clutch would be mineral oil compatible. Common sense would tell me they aren't, since there seems to be different seals for brake fluid components and mineral oil components.

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  • 9 months later...

I've just converted the front brake on my 2012 GasGas to a 2013 style brake.

As far as I can tell the 2013 style rubber cup and o-ring have the same dimensions as the 2012. At least on the brake of my GasGas.

So I guess if one would combine a new 2012 style clutch piston kit from GasGas (only the rubber cup and o-ring) with a 2013 Sherco clutch piston kit and lever, you can still use mineral oil.

Correct my if I'm wrong please...

Edited by guys
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I hope you now have a good reliable set up. It is a great shame that you and many others are having to pay out such a lot of money to correct something that is basicly an obvious design fault, you can see that the lever is going to apply an uneven push on to the piston. It's a shame some of the skilled engineers involved in building the brakes and the bikes couldn't see it...

It also wouldn't hurt some sort of good will gesture from manufacturers to at very least supply upgrades at cost or discounted prices.

TLTEL

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I bought the bike second hand so I guess I'm not entitled to warranty, but I know of some guys in Belgium that bought their bike new and got a free replacement (AJP)

Edited by guys
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