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Tv175 disc brake squeal

Posted: Fri Dec 04, 2020 7:24 pm
by Davidsquaredson
Hi, I’ve got an original disc brake. New pads and copper grease ion their edges. Drilled out 3 holes in the disc to the slightly larger recommended size. Put copper grease on the 3 pins. Small amount, just enough to help free play

My brakes work well but are squealing. Any ideas why?

Thx in advance
DdImage

And those spots are wired in as my turn signals , and the correct seat is now on.

Re: Tv175 disc brake squeal

Posted: Sun Dec 06, 2020 1:17 pm
by Warkton Tornado No.1
As you have received no responses, I'll state my opinion based upon experience.

The pads, being circular, tend to rotate, particuarly on the static side with it's central adjuster, which also means that it is pivotal with a low area of contact.

Copaslip is great stuff, but on the pad sides will encourage rotation.

TBH my road SX has a similar set-up to yours but I only lube the pads on their bases, & use sintered pads that I select to be a good fit. Fortunately, my brakes do not squeel, but if they did, I would introduce something to stop the rotation.

Within racing, prior to outboard discs becoming the norm, some riders used to go to the extremes of selecting pads with a small tab & notch a corresponding location slot in the backplate. Of course, if you were to notch the pads & fit a dowel 'half & half' to the backplate on both sides, this would achieve the same objective.

The other thing that the likes of LLRT did was to dispense with the adjuster & fit a shim beneath the static pad, effectively a large washer. Ha! In alloy for the weight saving!

We've been here before, but my preference is not to modify the disc itself & retain the anti-rattle circlip. If the disc is cleaned up meticulously on the bore & pin holes, along with the pins & disc spigot it will not bind up & will run truer. My belief is that the disc can flutter a tad & encourage the tendency to squeel.

If you could @ least refit the anti-rattle circlip (nicely Copasliped) then that too should help.

Re: Tv175 disc brake squeal

Posted: Wed Jan 06, 2021 4:57 pm
by Davidsquaredson
Hey, thanks so much for this. I went with sintered pads and on the static side it was a very tight fit. I assumed that was wrong and sanded the edges to allow up / down motion. So I made it worse. Duh.

I will put this scoot up on the bench this weekend and pull the brake and start over, following your advice. Thanks again


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Re: Tv175 disc brake squeal

Posted: Thu Jan 07, 2021 5:48 pm
by Shipleystevep
I can’t help I’m afraid, my SX200 squealed with cintered pads. I just put up with it and eventually it stopped on it’s own. I never found a solution.
As an aside, I’m not a fan anyway my well set up hub with shoes on my SX150 is a much better brake.

Re: Tv175 disc brake squeal

Posted: Fri Jan 08, 2021 3:32 am
by Warkton Tornado No.1
Shipleystevep wrote: Thu Jan 07, 2021 5:48 pm I can’t help I’m afraid, my SX200 squealed with cintered pads. I just put up with it and eventually it stopped on it’s own. I never found a solution.
As an aside, I’m not a fan anyway my well set up hub with shoes on my SX150 is a much better brake.
"All sintered pads are equal, but some are more equal than others"

The really hard, racing pads appear to work @ their best when they get hot & are then very good. A different grade is better for road use, though I can't remember where I acquired the ones in my SX.

IMO the TV175 S1-2 drum brakes with reverse pull are extremely good & was all I could afford when I wanted to upgrade from cable disc in the 70's/80's. That said, the drum lacks feel in the wet & if you get the right pads, discs can work well, but more so with a good hydraulic as MSC used to sell.