Rear brake components bent?

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BlackIP2
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Rear brake components bent?

Post by BlackIP2 » Thu Mar 29, 2018 8:43 pm

Trying to find out why my IP2's back brake is pretty rubbish, I have stripped it down to find, surprisingly, the mountings on the rear torque arm are not parallel.
Torque arm.jpg
Torque arm bolts fail to align against the straight edges of a tool tray.

The arm's mounting on the rear caliper bracket is also out of alignment with the wheel spindle.
Caliper mount.jpg
This is surely NOT how it was designed to be, or am I missing something here?

Closer examination of the caliper mounting reveals some play whilst it sits on the wheel spindle, which I believe results in my final discovery of the brake pads being unevenly worn - ie, the mounting is twisted when everything is bolted up tight, forcing the caliper into a slight angle.
Rear pads.jpg
I can only imagine that at some stage, maybe during its police life, the torque arm must have got a big bump and was then straightened out, as there are signs of a kink in it, but no one checked whether it had bent anything else.
Unless anyone has any bright ideas, seems to me I need a new torque arm and caliper mounting bracket?
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fogrider
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Re: Rear brake components bent?

Post by fogrider » Fri Mar 30, 2018 10:25 am

I'm not familiar with the Interpol, but my first thought is to check the chain and sprockets, are they in a straight line ?, if not, maybe the rear wheel spacers are wrong , just a thought,
Regards, Terry.

fogrider
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Re: Rear brake components bent?

Post by fogrider » Fri Mar 30, 2018 10:30 am

AFTER I had mentioned about chain line, my PC finally downloaded the photo's, that looks like crash damage to me, even the worlds worst mechanic would not assemble that. Current MoT.?......by whom ?

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Richard Negus
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Re: Rear brake components bent?

Post by Richard Negus » Fri Mar 30, 2018 10:38 am

It CERTAINLY wasn't meant to be like that!
The aluminium mount plate for the caliper is machined with all the bores parallel and the torque arm should be straight with the bushes welded on at a slight angle.
With the grease nipple at the 9 o'clock position, your plate is one of the early ones. Later versions, also fitted to the Classic, have the nipple at about 7 o'clock and a slightly larger boss at the spindle pivot.
Late torque rods have end bushes with thicker walls, but still use the same rubber bush.
The usual problem with this set-up is that the inner bush at the spindle pivot rusts, often due to pressure washing when in police use, clearance increases and the plate drifts out of alignment. When necessary, I make that bush in stainless.
Slower slower, no faster faster - the joys of old fogey mode to hooligan mode at the flick of a switch

BlackIP2
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Re: Rear brake components bent?

Post by BlackIP2 » Fri Mar 30, 2018 2:12 pm

Cheers guys.
Yes it does have an MOT - that fault obviously not picked up by the tester!
I didn't think it should be like that and suspected something was amiss.
I'll source a new torque arm and pivot plate, but by all accounts the back brake on IP2s and Classics aren't brilliant anyway?

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