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Brake caliper pin problem.

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ReggieV View Drop Down
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    Posted: 25 Feb 2019 at 20:54

The bike is an LM1 that I have recently very nearly finished building, and I've found on the front right brake caliper, that one of the two guide pin holes has managed to enlarge itself (thanks go to the previous owner for this) so that the wire "C" clip on the guide pin just fails to produce enough contact in the caliper's hole, so that it will not secure itself in the caliper. I can push it in and pull it out quite easily by hand without the spring clips in place. CryCryCry

So what to do?
One course of action is to buy another caliper.
Would it be possible to sleeve the enlarged hole in the caliper?
Drill two holes in the pin and put two R clips inboard at each side.
 
Has any of the collective had this problem before and if so how was it addressed?
Also any good ideas are welcome.


Edited by ReggieV - 25 Feb 2019 at 20:57
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TheWrongTrousers View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TheWrongTrousers Quote  Post ReplyReply Direct Link To This Post Posted: 25 Feb 2019 at 21:03
I have not heard of that before. If it were me, I would worry about creating some kind of dodge to get round the issue. After all, its a brake caliper and even though compared to modern bikes a LM1 is not the quickest bike on gods earth, they still go very fast and ones life depends on the calliper being 100%. I know you know that anyway, but its worth bearing in mind. What to do.

The first thing I would do is to get in touch with Ducati Paddy.  He is a font of knowledge, and is very helpful when it comes to problems with both carbs and brembo brakes. 

Here he is

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Post Options Post Options   Thanks (0) Thanks(0)   Quote FlyingTiger Quote  Post ReplyReply Direct Link To This Post Posted: 25 Feb 2019 at 22:44
if it was me i would bore the hole out and make an interference fit bush for the pin and if you were wanting to be super careful fit an R clip the pin as well. I give full respect to prevoius post as regards safety issues but as an engineer this would be standard practice in my world. I could do this for nothing with the resources available to me, but the cost to get a machine shop to do it would probably make a replacement  more favourable 

Regards 
Mark
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 25 Feb 2019 at 23:47
Got a horrible feeling any kind of apparent modification to a brake caliper might be an MOT fail. The repair would have to be very good to remain original in function and appearance, and not any kind of apparent "bodge". E.g. drilling holes for R-clips is out.


Many years ago I remember replacing a brake linkage on a Reliant with a nut and bolt (can't remember why exactly), but was later told can't do that, must be a plain clevis pin with a split pin, as per originally.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2019 at 07:51
Done properly, as flying Tiger says, there would be no problem, but a bodge job could kill you.
Brian.

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ReggieV View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ReggieV Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2019 at 09:46
Thanks to everybody for their replies.
I do of course take safety seriously, otherwise I could have for example put silicone in the hole with the pin or epoxy resin etc etc, i.e. a bodge, but I don't ever intentionally bodge anything.
 
After posting last night and reflecting on my comments, I quickly realised myself that an R clip wasn't a good idea if only because of the potential weakening of the pin, so sleeving / bushing seems to be the way to go. I do know a couple of engineers (one a Guzzi fan and retired) who may be able to help me with this, so thank you all again.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2019 at 10:07
For someone with the right kit it should be a fairly simple job.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jpc Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2019 at 11:23
Or this. It looks on inspection like an extra precaution and is at least as secure as the puny c-clips.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote iansoady Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2019 at 13:04
I must admit those C clips don't look as if they do very much. I'd rather have some sort of positive location.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Chris950s Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2019 at 15:11
Originally posted by Brian UK Brian UK wrote:

Done properly, as flying Tiger says, there would be no problem, but a bodge job could kill you.
I agree, bushing would be the way I would go too. Better than welding up the hole and re-drilling as the heat of welding could distort the caliper body. If the hole were opened up by someone with the right kit and bushes made to an interference fit, so there is no movement between bush and caliper body, then I think that would be a good job. Your local machine shop should be able to handle that.
Chris and Karen - Essex
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Post Options Post Options   Thanks (0) Thanks(0)   Quote theone&onlymin Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2019 at 16:31
Show of hands from anyone that has had a pin come out .
Just asking.

Cheers 
Min
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TheWrongTrousers Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2019 at 16:55
Never. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Chris950s Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2019 at 16:56
Mine are stainless steel and come out a treat, but only when tapped with a small hammer and then wrestled out with a pair of pliers. Center pins are stainless too. All supplied by Shaw Stainless 


I can't remember where I got the springs from, but they are stainless too.
Chris and Karen - Essex
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jpc Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2019 at 17:01
It's the leaf spring between the pads that holds the pins, not the c-clips.
If the pins REALLY rattle, why not drill at 7mm and have someone turn oversize pins, problem solved.

I think Eddie Lawson famously had a crash after the pads dropped out, and some mechanic was let go, and I mean FIRED !!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nab301 Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2019 at 19:35
Are they not the same caliper as fitted to BMW airheads and others  , (I'm assuming  they have the same piston dia and mounting bolt spacing .  Plenty of good ones available from the likes of Motorworks?
Nigel
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