Topic: New front caliper build pinching rotor

[ryanGDanderson]

I've been resurrecting a 75 CB750F and made it to front brake system. Original parts almost all too far gone, I built a shiny new system ordered from 4into1. After install and bleeding, the caliper is clamping the front wheel to where it cannot spin. When the two caliper bolts are loosened the wheel spins freely. The stationary end looks thicker than I expected. I took a pic, but apologies if it's trash. Though not in the photo, the piston can fully retract. 

I was wondering what I can do about this?

I figure my options are to grind down a bit of the metals on the stationary side's inside, and where that makes contact with the little bump on the back of the stationary brake pad... but for all I know that could be stupidly dangerous. Any advice for a noob?

[69cb750]

The back side puck may be to thick(?)
Compare to original puck, check nothing behind puck.

[scottly]

First of all, you shouldn't have to modify a new part. If you have incorrectly installed the fender brace between the upper caliper bracket and the fork leg, it can cause the caliper to be cocked and bind. The caliper bracket should be against the fork leg, with the fender brace on top of the bracket. Also, leave  the adjusting screw and spring off for now. If the mounting is correct, as well as the axle assembly, it may be yet another questionable product from 4into1? 

[newday777]

It may be yet another questionable product from 4into1?

I just installed short 2" bars with new short cable set from them and the nuts on the pull cable is stripped and pops off the thread several threads and doesn't tighten up. This was after they sent a regular set of cables instead of the short set I needed for the bars. Not a happy camper with them now......

[Shtonecb500]

can you take it apart and take pictures for us, let us see everything including the back side of stuff and your fender mounting, dont take away material anywhere yet....you dont have something lined up right.

[ryanGDanderson]

It may be yet another questionable product from 4into1?

I just installed short 2" bars with new short cable set from them and the nuts on the pull cable is stripped and pops off the thread several threads and doesn't tighten up. This was after they sent a regular set of cables instead of the short set I needed for the bars. Not a happy camper with them now......

I have had previous returns to 4into1, and so am a bit wary of them, but I haven't found another one(ish) stop shop for my needs. Any recommendations?

This leads to:

The back side puck may be to thick(?)
Compare to original puck, check nothing behind puck.

Unfortunately I may have scrapped the original caliper halves. I just took a quick look where I keep any old parts that I can't rebuild. The stationary pad, which I think you are calling the puck, has a base that is much thicker than appears necessary. That's why I was wondering if I can sand the base down some.

can you take it apart and take pictures for us, let us see everything including the back side of stuff and your fender mounting, dont take away material anywhere yet....you dont have something lined up right.

I took some pics in an attempt to answer your request. Apologies in advance if I misunderstood anything.

[ryanGDanderson]

can you take it apart and take pictures for us, let us see everything including the back side of stuff and your fender mounting, dont take away material anywhere yet....you dont have something lined up right.

For some reason the other pics didn't upload. One sec.

[grcamna2]

You might choose to sand down the extra thick stationary pad's friction material,rather than the steel backing plate.
The little bump on the steel backing plate part of the stationary pad should not be ground-off;it's there to help the stationary pad self-center,a pivot point.

[ryanGDanderson]

can you take it apart and take pictures for us, let us see everything including the back side of stuff and your fender mounting, dont take away material anywhere yet....you dont have something lined up right.

K done. Sorry for the repeated posts. Couldn't upload them at once for some reason

[ryanGDanderson]

You might choose to sand down the extra thick stationary pad's friction material,rather than the steel backing plate.

If that doesn't create any issue other than shorter pad life, I'd be fine with that. Another one of those things I considered before asking the wise folk here, heh.

[scottly]

Your caliper mounting looks correct. Please post pictures of the front axle on both sides so we can verify it's also installed correctly.

[ryanGDanderson]

Your caliper mounting looks correct. Please post pictures of the front axle on both sides so we can verify it's also installed correctly.

I attempted photos on both sides showing the mounting from the forward, rear, and face

[scottly]

Your axle mounting also looks correct. One last thing to try: remove the three caliper mounting bolts and see if the caliper is free on the disc. If yes, does the mounting bracket try to move towards the fork leg, or away from it?

[Keith]

Is your right side axle clamp missing?

[MauiK3]

That puck looks thick.
Another source for parts is Yamiya, good quality stuff, lots of nos

[ryanGDanderson]

Is your right side axle clamp missing?

Yes it is. I’m rebuilding the forks next and the parts are on the way, including that. Bike wasn’t in the best shape when I bought it

[bryanj]

In the very first pic the caliper looks to be at an angle to the disc, it shouldnt be

[ryanGDanderson]

In the very first pic the caliper looks to be at an angle to the disc, it shouldnt be

I wasn't able to satisfactorily photograph the angles such that it appeared as accurate as eyeballing it.

I think that, based on the excellent and valuable responses I've gotten here, my resolution is to wait on this issue until I rebuild the fork and wheel, so I can eliminate those angle/grime/etc variables. Then if still pinching focus on the "puck" pad, first sanding down the side touching the caliper to eliminate the gap, seen in the photograph where I am holding the assembled stationary caliper, between the caliper and puck. If that does not open the caliper enough for the wheel to spin then I will sand down the puck's pad material.

I am at peace with doing a little modification like this because I have a feeling that this may be a not-perfect fitment issue where this brand of brake pad isn't perfectly fit for this caliper for my rotor... despite the 4into1 claims.

Thanks everyone for the wisdom!

[BenelliSEI]

In the picture of you holding the fixed side of the caliper/pad, the pad material looks much too thick. It also appears not to be seated, down in the caliper. What’s the brown stuff between the pad and caliper? Scrape the paint off the metal backing plate and make sure that pad is seated properly.

[MauiK3]

I think the brown/reddish stuff may be anti-squeal disc brake goo.
I’m pretty sure that pad is wrong

[ryanGDanderson]

In the picture of you holding the fixed side of the caliper/pad, the pad material looks much too thick. It also appears not to be seated, down in the caliper. What’s the brown stuff between the pad and caliper? Scrape the paint off the metal backing plate and make sure that pad is seated properly.

I think the brown/reddish stuff may be anti-squeal disc brake goo.
I’m pretty sure that pad is wrong

Both correct. Red stuff is anti-squeak. The puck is very thick and not flush with caliper. I didn’t take a pic of the puck’s back but it has a small, off-center hump causing the gap.

[grcamna2]

In the picture of you holding the fixed side of the caliper/pad, the pad material looks much too thick. It also appears not to be seated, down in the caliper. What’s the brown stuff between the pad and caliper? Scrape the paint off the metal backing plate and make sure that pad is seated properly.

I think the brown/reddish stuff may be anti-squeal disc brake goo.
I’m pretty sure that pad is wrong

Both correct. Red stuff is anti-squeak. The puck is very thick and not flush with caliper. I didn’t take a pic of the puck’s back but it has a small, off-center hump causing the gap.

The non-stationary 'piston side' pad is the one that does all the work and it usually wears twice as much as the stationary pad,from what I've experienced:therefore removing some friction material from it will help clearance.
Does the caliper freely pivot from side to side on its mounting post ?

[BenelliSEI]

In the picture of you holding the fixed side of the caliper/pad, the pad material looks much too thick. It also appears not to be seated, down in the caliper. What’s the brown stuff between the pad and caliper? Scrape the paint off the metal backing plate and make sure that pad is seated properly.

I think the brown/reddish stuff may be anti-squeal disc brake goo.
I’m pretty sure that pad is wrong

Both correct. Red stuff is anti-squeak. The puck is very thick and not flush with caliper. I didn’t take a pic of the puck’s back but it has a small, off-center hump causing the gap.

I agree 100%. That is the wrong set of pads for your caliper. Start over.

[Remcod]

Did you by any chance swap the left and right puck?

The non stationairy puck has the dimple to fix the plastic ring. The stationairy one should however have an extension to fix it.

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[david 750f]

Did you by any chance swap the left and right puck?

The non stationairy puck has the dimple to fix the plastic ring. The stationairy one should however have an extension to fix it.

I think Remcod may be onto something here, the stationary pad should have the hole in it. The cotter pin goes through the pad to the stationary calliper. Have you reversed them? (I've never tried reversing them, but it may be possible).