Topic: Very rattly front brakes 750 twin disc.

[Old Moe Toe]

Got a major rattling going on with my front brakes. It's a twin disc set up with the earlier type "C-caliper mounts".
There is a small amount of up and down play between the c-caliper mounts and the beams that are held between them via the pivot pin.
You can see the gap and it is not much but by the time that play is at the actual brake caliper it makes a hell of a racket, especially on bumpy roads.
I am thinking a way to minimise this play would be to get a washer of reasonable thickness in stainless steel that the pivot pin can fit through. Then file or sand more material off either the top or bottom inside part of the c-caliper holder so that with the washer now in between it is a tight fit again.
No doubt others have tried this or some other method with good results.
Any tips or advice would be great.
Thanks
Brad

[robvangulik]

Is the pivot pin greased well, with o-rings on top and bottom?

[Old Moe Toe]

Not sure about o-rings.
I will have to check that, somehow I doubt it.
Just looked at the parts diagram and can see those o-rings,.... as well as 2 washers!.
No wonder I have a rattle.

[754]

Try o rings before filing or grinding..

[Old Moe Toe]

Pulled both the caliper holders off today and YES there were o-rings in there where they should be. They looked more like quad seals though (4 square sides in cross section) I guess due to age so I will put new o-rings in.
There were no washers in there though and looking closely at the parts diagram there are actually two different washers listed.
Washer A 10 x .1mm part number 45131-300-305  and
Washer B 10 x .2 mm part number 45132-300-305.
On the part number list it does not say use 1 or 2 of these, it has the letter "N" which means use as needed.
To me a washer that is only .1 or .2 of a mm thick seems pretty flimsy, but if that is what they say to use I guess that is what one should use.

I would be interested to hear from anyone who has used these washers to eliminate the gap between the c-shaped caliper holder and the beam that holds the actual brake caliper. Has the fix lasted well etc?.
Thanks
Brad

[Trevor from Warragul]

I contemplated using a shim for the exact same reason on my 350/4.  I ended up doing this instead.  Not original, but works very well.  When play reappears, just pump in more grease:

[Medyo Bastos]

I recently asked about the washers and got no input. Im installing both new seals and washers today!


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[Don R]

 Someone said they used feeler gauges with the hole reamed out to make washers. My single C brakes rattle too, I'll check the o rings.

[754]

So the one is similar to beer can thickness. Shims really.
 So can be made from beverage cans,  hardest part is the hole.. the rest can be done with good scissors....

[Old Moe Toe]

Thanks for the feedback.
Morini, that grease nipple is thinking outside the box!.
I have ordered new O-rings and a selection of the washers from DSS, so will have to wait patiently for them. Interesting that Yamiya did not sell the washers, they did sell the o-rings though.
754, beer can material just seems too flimsy to me. I would rather take more material off the c-shaped caliper holder and put in a decent 1mm thick or thereabouts stainless steel washer. Not sure what I am expecting from DSS with the .1mm and .2mm washers. I will wait and see.

[Medyo Bastos]

Frank is right though. They’re about the thickness of a bud can. I think bud dry would work the best. I found them at cmsml.


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