Curiosity got the better of me...
The reason I bought this were two fold really. I wanted to see what they were like and also, my std master cylinder (and lever) is scuffed up following a crash by the previous owner. If this turned out ok then its win/win, if not its £20, no biggy. Everyone is so quick to call them shit without seeing them, same happened with the pazzo levers years ago.
I have used the Chinese Pazzo copies before, had a few sets. They are cheap, well made and easy to get hold of. I got the first pair because my garage used to have a split front, back with a std door between. I was risking breaking my OEM levers so got the cheap ones to avoid damage. I was impressed with them so got a few.
I have seen the master cylinders before on alibaba etc but never really found any decent write ups about them. Forum guys all tell you that they are death traps made of cheese and all have a "mate" who almost died just ordering them. I did find a few articles but they were the older (2006 ish) copies of the earlier brembo units. They found that they couldn't get any pressure in them, fluid leaking past the nipple threads, seals not sealing, return circuits being blocked by the seals etc which isn't great, but 10 years on things must be better right?
For £20 I took a punt just to see really, whats the worst that can happen?
We are talking about these:
This is a copy of the Brembo 19 RCS 18x20 master cylinder. The sites say they are CNC billet but they are in fact just cast. The real Brembo (I have one for direct comparison) isn't CNCd either, its forged but does have some CNC surfaces on it.
It comes with 1 line banjo bolt, bleed nipple with dust cap, reservoir, pipe and clips.
The real Brembo has two holes on the underside to accept a microswitch for the brake light, the copy also has these in the same position so the std microswitch should fit fine.
The lever is cnc'd and isn't too bad at first inspection. It's a fold up type like the original but for some reason the copy uses a bolt and a pin to stop it folding up in normal use. The real one uses a bolt and nut to simply clamp the two halves together.
The dust cap on the piston doesn't fit in any way and was supplied just flapping about on the piston actuator pin. Not really confidence inspiring. A few pulls on the lever and it has a somewhat rough action but it's dry so lets not be hasty.
Here you can see the lever "hinge". It's exactly the same setup as the original but has an extra pin and the bolt is flush at the back. The real Brembo has a longer bolt with a nut on the back and no pin.
The print etc is nice and clean.
It uses a bushed (steel) pivot which was nice to see, I was expecting it just to be plain...
The copies main pivot is a large gold aluminium pin with a flange at the top and c-clip on the bottom. The real Brembo has a black hollow steel pin that is flush at the top in a recess and has a nut on the bottom. I did wonder why they would go to the trouble of using the oversized gold pin on the copy but a look at the Brembo catalogue shows the MotoGP/top end ones use a gold pin like this (although that is sunk into the body rather than sat on top). Presumably those are TiNi coated.
So, whats it like inside
Removing the lever is easy enough, C-Clip off and pull the pin out.
The surfaces are nice and smooth with decent edges etc. The piston is behind the stop plate and a cir clip. The "cup" protruding out is the socket that accepts the actuator pin from the lever (that allows the 18x20 ratio adjustment). The surface is proper rough (thats clean there, no grease etc) and when pressing the lever you can feel the actuator pin snagging on these machining ridges.
On the bench out of focus is the actuator pin and dust seal (which wont actually fit anywhere). On the real one this presses in on top of the cir clip but you can clearly see on the copy there is just not enough room for it.
Lets pull it apart:
This is the piston, seals, stop plate and return spring. The piston looks ok, not a brilliant finish but ok. It has some scratches on the large diameter sections. The seals just don't fit it though. It's not like a bad tolerance either, they are probably 1mm too big for the shaft diam and they also move back/forth! The stop plate is a standard stamped washer, about 2mm thick.
The bore is actually very good apart from one little detail.
The reason for the scratchy feel when pulling the lever, and the scratches on the piston is here:
The large hole for the reservoir line is simply drilled from the outside and then thats it.... its burs are in tact!. In fact all the drilled holes leading to the main chamber are bured. I cleaned them up and the piston scratches. Feels much better, but not great. The piston+seals are not that brilliant fit wise.
Measuring the seal lips and return/res circuit holes it looked ok, nothing alarming.. So nothing left but to bleed it up.
I had a set of calipers/lines to use so I can do this off the bike as I didn't fancy fitting it only to have to refit my std one if they were crap.
So, here it is on my "bench rig":
I have to say, with the master cylinder having a bleed nipple these have to be the easiest I have ever done. Baring in mind the master cylinder, lines (full length - the std ones of my fazer in fact) and callipers were empty of oil, it all came up in a few mins.
No leaks at all so I left it tie wrapped on all night to see if it leaked in the morning. It didn't. They feel ok, a bit like the std ones but you need to pull the lever about an inch before anything happens, the piston isn't being held in the right position, it needs to move back about 2mm or so.
The reservoir is tiny however, its like a small rear one off a pit bike.
So, I fit them to the bike and went for a spin. I have no micro-switch for this so had to remember to simultaneously use the back brake to get the light on.
First off they are massively more powerful than std. The first inch movement aside, when they are on the feel is really good, adjusting power is very nice, buttery smooth and one finger is enough (I need two on std).
The hinged lever, I mentioned it has a pin to stop it rotating. This worked out, I had to keep pushing it back in, confidence inspiring. I found if I slowly pulse the lever while its applying force to the disks I can get it to come back to the bars (takes about 15 slow small pumps to do this) indicating the seals are not sealing (or maybe they are moving on the piston as they are sloppy).
To tale this to the Nth degree, I went to my dads and we made a new piston. This was machined correctly and the correct diam for the seals and its held in the right place to eliminate the inch of lever travel before it does anything. So, the seals now seat properly and can't move fore/aft. Straight away just fitting the standard seals you can see its better, the lips stand up proud for a start. A test in the bore and yeah, silky smooth.
The dust seal that doesn't fit anywhere, we corrected this by replacing the 2mm washer stop plate with a thinner steel shim and used a slightly thinner but larger (and better made) cir clip. This allowed us to fit the dust seal under the cir-clip so the whole lot is held firmly in place.
The hinged lever, I removed the pin and replicated the original Brembo setup of simply having a longer bolt with a nut at the back and clamping it up. Works very well, like a proper Brembo and doesn't require the extra hole drilling and pin inserting. Odd that they do that.
Remember the bushed pivot on the lever? Measuring it and its 8.25mm bore at the bottom, 7.9mm at the top.... Impressive. The gold alloy pivot pin is 7.9mm so is sloppy at one end. The holes on the master cylinder are both 8.25mm so its pretty sloppy. So we are maknig a new pin and bush, boring out the master cylinder holes to get a decent, slop free action.
With these mods it now feels just like the real Brembo RCS I had to compare to, very impressive really.
It's odd that the Chinese seem to get 90% the way there then just seem to not bother. It wouldn't take anything on their part to correct the issues, its much more work to correct them after the fact. If they did that then they would be a very good product.
I have seen that they are now doing replicas of the latest MotoGP ones with the recessed TiNi pivot pin that does look like it is CNC'd but they are £60 or so. Too rich for my blood. Might see what Santa brings.
Would I recommend one?
No. Not unless you can sort them out like this.
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