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Shimano recall - CX75 Disc brake caliper

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Shimano recall - CX75 Disc brake caliper

Old 08-26-13, 04:26 PM
  #1  
bikeinxs
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Shimano recall - CX75 Disc brake caliper

http://bike.shimano.com/publish/cont...recall_by.html

I have not been able to find anything on why or what the issue is.
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Old 08-26-13, 06:41 PM
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I've been using the CX75 calipers on our tandem and have come across two issues one of which is more of a nuisance, the second one would potentially make the caliper function poorly or not at all in terms of braking. I suspect it may be the latter issue that is involved in the recall as this link suggests that the problem is related to adjusting the pads. http://cycle.shimano-eu.com/publish/...recall_by.html.

The first problem is also related to adjusting the pads. It involves the leaf spring which is used to create a detent when the inner pad is adjusted. I had this spring work out of its normal position and cause a pinging sound as the wheel rotated because it was coming in contact with the rotor or it was not allowing the inner pad to retract fully and the pad was the source of the pinging (not sure which). That was easily solved by placing a dab of gasket forming silicone sealant on either end of the spring to keep it in place.

The second problem surfaced when I inspected and adjusted the pads on the front caliper. With the pads removed I depressed the brake lever actuating the caliper piston. After replacing the pads and adjusting them I grabbed the brake lever and everything seemed fine. I depressed it a second time and it went all the way to the handlebar. Thinking I had broken something I disassembled the caliper and found that there are three ball bearings which ride in tapered grooves involving the actuating arm. As the arm is moved the balls ride into the shallower portion of the taper moving the piston inwards. I realized that by actuating the arm without pads installed I had probably moved the balls out of the groove. With the balls in that position I had adjusted the pads after reinstalling them. Upon activating the caliper lever a couple of times the balls moved back into the tapered groove. This created a situation where there was too much travel in the system to be taken up by the brake lever without adjusting the pads a second time.

I could see a scenario where someone does what I did but instead of uncovering the issue on the stand actually goes out for a ride and finds out the hard way things don't work. I was getting ready to write up a 2,000 mi review of the CX75 calipers to post in this forum but I guess it is a moot point now. It seems that Shimano will be replacing the CX75 calipers with the newer CX77 model as indicated in the above link. I'll write a review when I get some miles on my "new" CX77 calipers!

Curt

Last edited by Krenovian; 08-26-13 at 07:01 PM.
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Old 08-26-13, 11:59 PM
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Chris_W
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I have used a CX75 and R515 on a couple of bikes for a few months now. The only problem that I've had with them is that the inner/fixed pad seems to wear quite fast, and soon the rotor is pushed against the caliper body instead of the inner pad, which has worn below the level of the body. Braking performance is obviously then substantially reduced. This means that I really have to stay on top of pad position readjustment. I haven't had this problem with a couple of BB7s that I've used for much longer, I believe because the caliper body on those doesn't protrude past the pad even when it's worn down. It'll be interesting to see whether this will change with the new Shimano models.

I've also found that the higher-end CX75 gives a much more solid braking feel and more power than the R515 even though externally they appear to be almost identical. This was when using them on two different bikes with different brake levers, so I wasn't 100% certain that this was due to the brake; I've therefore just switched the R515 for a CX75 and kept everything else the same on that bike and this week I'll hopefully have time to perform the test to know whether that makes the difference. I'll report back here.
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Old 08-27-13, 10:03 AM
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This may help. It doesn't tell why but shows how to ID a recall caliper. http://www.bicycleretailer.com/recal...s#.UhzKWX_LIkQ
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Old 08-28-13, 04:12 AM
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Originally Posted by Krenovian View Post
The second problem surfaced when I inspected and adjusted the pads on the front caliper. With the pads removed I depressed the brake lever actuating the caliper piston. After replacing the pads and adjusting them I grabbed the brake lever and everything seemed fine. I depressed it a second time and it went all the way to the handlebar. Thinking I had broken something I disassembled the caliper and found that there are three ball bearings which ride in tapered grooves involving the actuating arm. As the arm is moved the balls ride into the shallower portion of the taper moving the piston inwards. I realized that by actuating the arm without pads installed I had probably moved the balls out of the groove. With the balls in that position I had adjusted the pads after reinstalling them. Upon activating the caliper lever a couple of times the balls moved back into the tapered groove. This created a situation where there was too much travel in the system to be taken up by the brake lever without adjusting the pads a second time.

Curt
Curt, I've been told that your second problem is the reason for the recall.
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