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General / Chinese Brembo Master Cylinder copies/fake (latest version)
« on: 25 October 2019, 08:56:54 am »
I decided to have a look at these new Chinese Brembo master cylinder copies, I previously had one of the older type (a copy of the 19 RCS). The older ones, certainly the one I got, had a number of issues that in my opinion made them unusable without a fair bit of modification - as I mentioned in the post I put up - some were minor, like the rubber boot not fitting, some were major, like the piston being completely wrong and the pivots being not only soft alloy but the wrong size. I stuck this on the FB page but thought I would stick it here as I have now used it for enough miles to uncover any potential issues.
Anyway - I later fitted one of the new (at the time) clutch perch/levers that were actually much better made. Around the same time they started offering these new master cylinders that appeared to be a step up in quality.
As some sort of disclaimer or waiver of responsibility - I don't sell these nor would I actually recommend getting one unless you know what you are doing. I don't condone cheap copies etc but in the interests of "taking a gander" I am putting this up -I find it interesting at the very least.
So - first off, the price - I got this on an Aliexpress flash sale for £15 - delivered......from the other side of the world...
It is a copy of the Brembo RCS 19 Costa Corta.
It arrived in 6 days.
First off, it looks great from a quality perspective. Feels solid, certainly a big step up from the old version. It looks like the type of thing you might use to fight crime with in some of failed dystopian future...
It comes with everything required to fit, bolts, brake light switch, reservoir + hose etc (the reservoir is fine but it is still very small, the same as the older versions - like a pit bike one)
Taking it apart for a closer look.
The business end of the lever.
It is a beefy lever, seems quite well make - it even has the rubber grommet covering the 18/20 adjuster.
The span adjuster is vastly improved from the old version, this actually works for the full range. The previous ones had an ill fitting tension spring that would not give any resistance to the screw when adjusting from the standard position - this would cause the screw to wobble and eventually fall out as it was just a loose fitting screw adjuster. This new one is actually very good and works well with a decent feel to the turn.
This second adjuster (which sits vertically) is supposed to adjust some sort of bite point but in fact does nothing. It is purely cosmetic on this copy, it spins as it should and has a lovely polished pivot pin and nice retaining holes but in the end that is it... again - why they go to all that trouble then not actually have it do its function is a mystery. Needless to say, I set it to its Race position.. because fast.
You can also see the pivot bushing. This is now well made and needed no modification. The old versions were weird, they looked like some sort of cast tube that had a big difference in diameter at the top/bottom.
The back side of the lever, where the actuator rod fits is still the eccentric cup setup - you turn it and it alters the angle the rod pushes the piston. I mean, it does work and it is cleaner than the previous ones, smooth in the cup etc. You can see the bolt holding the lever end (so it rotates up in a crash rather than snapping) still uses the rolled pin. Real Brembos don't have the pin, they use a longer bolt with a nut and is simply clamped up. I will do the same to this if I keep it on. The whole lever is pretty nice though, it all fits nice and firm and has no real wobbly/play in the pivots etc
The rubber boot covering the piston/actuator fits nicely and shock horror, evidence of some sort of assembly grease being used! Unheard of on the old ones!! You can also see the brake switch which fits on the under side of the unit. The switch looks fine to me, waterproofing is there etc. The connectors are not the same as the Fazer so I had to cut them off and stick some appropriately sized blade connectors on. All the surfaces are clean and sharply cast.
Removing the rubber boot uncovers the piston front face and the retaining clip. Again, looks fine.
Its not fine though... I only noticed when putting it back together because, well, you don't expect to have to check but the clip has no retaining groove. They are simply relying on the steel clips edge to bite into the softer ally bore wall. Lovely. This is very risky because it isn't fail safe at all, this clip holds the brake together essentially, it also means the piston resting position to be set by pure chance as it rests with a spring pushing it to the front against the clip to set it...
You can see here the plain cylinder bore with no groove for the retaining clip. The main bore itself is good though, the previous ones had burrs around all the entry/exit pathway holes for the fluid circuits, these new ones are all nicely finished.
So, into the lathe it goes to cut a seating groove.
We had to make a little mounting plate to get it setup in a 4 jaw chuck as there was no real way to grip it securely. This is the underside of the master cylinder and you can see the banjo bolt hole and main lever pivot holes. They are fine.
So, with a groove now cut, this is the piston. Again, this is vastly improved over the old units. The seals fit well and they have nice proud lips. Previous ones had very badly fitting seals and a new piston had to be made. You can see the return spring at the rear of it as well as the little internal cap/seat that pushes on the back of the master cylinder bore.
The circlip holding this together is really too small, you can see how it is stretched (and on removal it has actually bent open) so I stuck a correct sized one on. This isn't really an issue but as it is the main brake I thought it best to sort it.
Built it all back up and fitted to the bike. As with the last one this bled up extremely easily with the upper bleed point, the switch works for the light. I had to make a mount for the reservoir as the supplied one is a straight type piece but it needs to be held about an inch further forward.
I have had this on now for just over 4000 miles and it has been great, feel and power are very good - it shares the same geometry as a real unit - and it has held up very well, it is still solid and no additional wobble from any of the pivots - it has less wobble than the OEM one I took off. The main pivot pin is aluminium (anodised gold) which isn't really ideal but it is a solid 1/4 inch size so it isn't going to break. It is showing signs of wear on the anodising so I will make a steel one I think.
They are still not a viable solution for fitting and forgetting though, they still need work to make safe IMO so I can't readily recommend them as a usable product, they are also copies which is not a great thing in itself. You could argue that for £15 in a pinch you could fit one but they take days/weeks to arrive depending on how lucky you are so that doesn't really make sense - you could quickly find an OEM one in that time. The upper bleed screw is also a little too long, it looks a bit naff being stuck out so much so it needs either turning down or a replacement shorter one being sourced.
Hopefully if you are contemplating trying one if these you might think twice and save your cash. If you can modify it yourself then they do become viable but you would want to be confident in your work for obvious reasons.
Anyway - I later fitted one of the new (at the time) clutch perch/levers that were actually much better made. Around the same time they started offering these new master cylinders that appeared to be a step up in quality.
As some sort of disclaimer or waiver of responsibility - I don't sell these nor would I actually recommend getting one unless you know what you are doing. I don't condone cheap copies etc but in the interests of "taking a gander" I am putting this up -I find it interesting at the very least.
So - first off, the price - I got this on an Aliexpress flash sale for £15 - delivered......from the other side of the world...
It is a copy of the Brembo RCS 19 Costa Corta.
It arrived in 6 days.
First off, it looks great from a quality perspective. Feels solid, certainly a big step up from the old version. It looks like the type of thing you might use to fight crime with in some of failed dystopian future...
It comes with everything required to fit, bolts, brake light switch, reservoir + hose etc (the reservoir is fine but it is still very small, the same as the older versions - like a pit bike one)
Taking it apart for a closer look.
The business end of the lever.
It is a beefy lever, seems quite well make - it even has the rubber grommet covering the 18/20 adjuster.
The span adjuster is vastly improved from the old version, this actually works for the full range. The previous ones had an ill fitting tension spring that would not give any resistance to the screw when adjusting from the standard position - this would cause the screw to wobble and eventually fall out as it was just a loose fitting screw adjuster. This new one is actually very good and works well with a decent feel to the turn.
This second adjuster (which sits vertically) is supposed to adjust some sort of bite point but in fact does nothing. It is purely cosmetic on this copy, it spins as it should and has a lovely polished pivot pin and nice retaining holes but in the end that is it... again - why they go to all that trouble then not actually have it do its function is a mystery. Needless to say, I set it to its Race position.. because fast.
You can also see the pivot bushing. This is now well made and needed no modification. The old versions were weird, they looked like some sort of cast tube that had a big difference in diameter at the top/bottom.
The back side of the lever, where the actuator rod fits is still the eccentric cup setup - you turn it and it alters the angle the rod pushes the piston. I mean, it does work and it is cleaner than the previous ones, smooth in the cup etc. You can see the bolt holding the lever end (so it rotates up in a crash rather than snapping) still uses the rolled pin. Real Brembos don't have the pin, they use a longer bolt with a nut and is simply clamped up. I will do the same to this if I keep it on. The whole lever is pretty nice though, it all fits nice and firm and has no real wobbly/play in the pivots etc
The rubber boot covering the piston/actuator fits nicely and shock horror, evidence of some sort of assembly grease being used! Unheard of on the old ones!! You can also see the brake switch which fits on the under side of the unit. The switch looks fine to me, waterproofing is there etc. The connectors are not the same as the Fazer so I had to cut them off and stick some appropriately sized blade connectors on. All the surfaces are clean and sharply cast.
Removing the rubber boot uncovers the piston front face and the retaining clip. Again, looks fine.
Its not fine though... I only noticed when putting it back together because, well, you don't expect to have to check but the clip has no retaining groove. They are simply relying on the steel clips edge to bite into the softer ally bore wall. Lovely. This is very risky because it isn't fail safe at all, this clip holds the brake together essentially, it also means the piston resting position to be set by pure chance as it rests with a spring pushing it to the front against the clip to set it...
You can see here the plain cylinder bore with no groove for the retaining clip. The main bore itself is good though, the previous ones had burrs around all the entry/exit pathway holes for the fluid circuits, these new ones are all nicely finished.
So, into the lathe it goes to cut a seating groove.
We had to make a little mounting plate to get it setup in a 4 jaw chuck as there was no real way to grip it securely. This is the underside of the master cylinder and you can see the banjo bolt hole and main lever pivot holes. They are fine.
So, with a groove now cut, this is the piston. Again, this is vastly improved over the old units. The seals fit well and they have nice proud lips. Previous ones had very badly fitting seals and a new piston had to be made. You can see the return spring at the rear of it as well as the little internal cap/seat that pushes on the back of the master cylinder bore.
The circlip holding this together is really too small, you can see how it is stretched (and on removal it has actually bent open) so I stuck a correct sized one on. This isn't really an issue but as it is the main brake I thought it best to sort it.
Built it all back up and fitted to the bike. As with the last one this bled up extremely easily with the upper bleed point, the switch works for the light. I had to make a mount for the reservoir as the supplied one is a straight type piece but it needs to be held about an inch further forward.
I have had this on now for just over 4000 miles and it has been great, feel and power are very good - it shares the same geometry as a real unit - and it has held up very well, it is still solid and no additional wobble from any of the pivots - it has less wobble than the OEM one I took off. The main pivot pin is aluminium (anodised gold) which isn't really ideal but it is a solid 1/4 inch size so it isn't going to break. It is showing signs of wear on the anodising so I will make a steel one I think.
They are still not a viable solution for fitting and forgetting though, they still need work to make safe IMO so I can't readily recommend them as a usable product, they are also copies which is not a great thing in itself. You could argue that for £15 in a pinch you could fit one but they take days/weeks to arrive depending on how lucky you are so that doesn't really make sense - you could quickly find an OEM one in that time. The upper bleed screw is also a little too long, it looks a bit naff being stuck out so much so it needs either turning down or a replacement shorter one being sourced.
Hopefully if you are contemplating trying one if these you might think twice and save your cash. If you can modify it yourself then they do become viable but you would want to be confident in your work for obvious reasons.
Had to leave a pair of emergency undies on the other side of the road as I wasn't prepared to stop traffic for them haha so just kicked the remaining bits of top box off the road and left it at that! Could have been worse I suppose.
