Brake caliper problems

[Saesneg Shaun]

Another day, another problem.

I found why my front brake was dragging and hardly worked. The piston was catching on the little brake pad retaining screw poking through the back of the pad and pushing the pad at an angle so I only had about 25% contact. This seems too have caused the pad to tilt in the caliper and jam.

I've shortened the screw slightly to avoid catching the piston (which now has a nice groove in the lip) but should there be a dust seal on the piston and pad?

[Bryanj]

What brake pad screw, there isnt form

[Saesneg Shaun]

Its the piston side pad locating pin that screws into the metal backing of the pad. Its was too long and fouling the brake caliper piston lip

[Saesneg Shaun]

this one. You can see slight damage to the lip where it rubbed before I trimmed it.

[Saesneg Shaun]

Ok problem sort of solved.
My bike is completely missing the seat pad part number 45151-300-000.
The 'mechanic' who previously owned this bike must have thought it not necessary!

I'd assumed the locating screw/pin was aftermarket and too long not that a whole piece was missing from the setup.

I ordered some stuff from DSS last week. Now it looks like I have to pay their extortionate delivery charges again!
 

[Bryanj]

Ah, never thought of that as a screw as never seen one removed, as well as the piston piece you are missing there should be a nylon spacer between pad and piston

[Saesneg Shaun]

Ah, never thought of that as a screw as never seen one removed, as well as the piston piece you are missing there should be a nylon spacer between pad and piston

Ah I don't have that either. Ordered the pad seat from DSS now. Can't see it on the parts diagram, is it something I can make up?

[Bryanj]

Used to come with the pads, somebody tried to tell me it was to try and stop brake squeal but i have my doubts, many bikes went without it back in the 70's due to cost of O.E. and not being in with pattern ones

[honda-san]

That nylon spacer is only used on the 350 - 400 - 500/4's which have a solid caliper piston surely?

The CB750 (up to K6 at least) should as pointed out have the (missing) seat pad which fits in the end of the hollow caliper piston. At least that's how my fours have been configured these last forty years.

Chris R.

[Bryanj]

The smaller fours have hollow pistons with a crimped in disc Chris, its a long time since a did a 750 caliper job so happy to be wrong, always thought the allen bolts through the wheel was not one of Mr Hondas best ideas

[Saesneg Shaun]

I'll see how I get on without the nylon spacer. I've no doubt the pads are pattern parts so probably never came with it.

[Bryanj]

Thing is you cant find it on any parts list anyway

[K2-K6]

I've never seen a nylon spacer on 750 caliper either.