Topic: Calipers and wheels and stuff

[phil71]

Hi everyone,

I've got a '71 CB750K1.  i recently replaced the front wheel, tree top and fender. While i was in there, I put some new pads in and now they squeal like a pig! (except when you're stopping) . It's also a little tough to push.. but not too bad.
    So, I got on the trusty forum just now, and I'm sure it's just that i didn't clean out the piston area too well, also the pads have a LOT of paint on them.. so I'll address that first.. BUT, that same thread talked about the lower fork caps, and that they're directional (who knew) ?!  I know I didn't pay attention to that when I disassembled, just made sure to mark LH/RH.
   This i find out AFTER taking a hell of a blast today on the highway!
Anyway, I go and consult my shop manual, and they don't talk torque specs for those nuts.
NOW I'm totally paranoid that I got this wrong.
  I'm attaching some close ups of the assembled lower forks. Any advice or criticisms are welcome.
Thanks!

[scondon]

When you look at the underside of the cap is there a directional arrow cast on the surface? If there is just be sure it's pointing forwards. When installed correctly there will be a gap at the rear after the cap has been tightened down. I see the gaps in your photo, just can't tell if their in the front or rear.

[phil71]

Thanks! I'll look for the arrows. One thing though, the older thread about squealing brakes had this to say
 

Do you think aligning the front forks may help? As per:

You might need to align the front forks, but first, check to make sure you got the front axle & nut on the right way (some other post here noted they got the nut on the wrong side, an old error I've even forgotten, but common...). Also, make sure the axle caps (on the ends of the forks) are installed properly. They should be flat and even at the back side with a (parallel) gap on the front side. Tighten the rear sides first, then the fronts. The caps are DIRECTIONAL: they have a HI and LOW side to them. The gap side must be in front.

To align: loosen the lower fork clamp (triple tree) bolts just enough to be loose, then finger-tighten them. The top ones should be tight, as per normal, so the tubes don't slip up during this next part. Loosen the bolts to finger-tight on one side of the fork brace (usually the non-brake side is easier). The next step is easier with a friend standing by with a wrench: get on the bike, on both wheels, and pump hard down & up several times on the front end. Try to hold it down on the last "bounce" (just don't let it all the way up), then have your friend tighten the lower triple tree bolts. Then let up and tighten the fork brace. This relieves little stresses all over, providing your tubes are straight.
 Could it be that the disk may be slightly out of align?
Cliff.

so... is that wrong? I'm really surprised that something that could seemingly affect safety would be left out of the shop manual.
Thanks!
Phil

[scondon]

I have a '78 750F, and the forks are different. Also, the brakes are behind the fork leg rather than in front like yours. Just to say that I could be wrong about yours. On mine the gap is in the rear when the caps are installed.

Hopefully we'll keep this post up top until another K owner that KNOWS can chime in 

[phil71]

Yeah.. I think I may keep 'er just in 'puttering' mode till i find out if I did this right.. I don't need the axle coming out from under me when I take another cobweb-blowing blast down a lonely road.

[bryanj]

Somewhere on the board are all the Honda bulletins and there is one on this subject in there

[Kong]

What do you mean the pads had a lot of paint on them?  Why do your pads have any paint on them at all?

[SohRon]

Paint on the pads and especially on the inside of the caliper could cause problems as Honda left these areas free of paint originally and there isn't much room for it in these locations. Removing the paint might help. Also, I've always been told  that the axle clamps must be installed with the gap to the rear, contrary to whats been indicated above; naturally the manual says nothing about this. I got this from a Haynes for the 550, but I believe the 750 is similar if not the same:

[Johnie]

If you have trouble pushing it I imagine the piston is not retracting. Take a rubber mallet and give the outside of the caliper a couple waks. That should at least loosen up the pad on the rotor so you can push it around. But it will stick again if you push the brake. For sure a caliper rebuild is in order including a new seal. The seal sits in a groove and that groove is gunked up. I use a Dremel with brass brush to clean it out. There is some good info on the board about rebuilding that caliper. Good luck with it. Nothing worse than squealing brakes. On a side note...if that brake centering adjustment screw is out of wak that could cause it to act like the brakes are on a bit. That screw is on the arm that holds the caliper.

[phil71]

There's no residual pressure in the line, and cracking a bleeder/banjo bolt doesn't make any difference. plus it's only slightly hard to push, by no means stuck.
 I ordered pads from a place in canada called vintage750, and the backing plates were painted black, which I thought was odd. They WERE on the cheap side. This is before I found "Cycle Parts Warehouse"... (they are kind of amazing)
 Anyway, I'm going to clean the gap, relube and sand those backing plates clean today. The adjuster, as things are now, will make things worse, but not better.

SohRon, that is AMAZING. that might be the first and only time a Haynes manual came in handy for me... for years I've thought that the level of detail in the Haynes and Clymer manuals  is best suited for toys. I stand corrected.
Thanks all for the great tips and suggestions!
Phil

[SohRon]

for years I've thought that the level of detail in the Haynes and Clymer manuals  is best suited for toys

I don't know much about the 750s, but the Haynes and Clymer manuals for the 550 cover several areas of the bike in much better detail than the official shop manual does, including more drawings and diagrams. I actually have all three for reference and that seems to work out pretty well for me.

[phil71]

Hi guys, just a follow-up and a thanks. My fork caps appear to be on correctly. I pulled the caliper and sanded the paint off the brake pad, then gave a nice new surface to bore the pad sits in, and cleaned it out till it shined. Put a light coat of grease and re-assembled. Bingo, no more squeal, and it's stopping beautifully.
Thank you all, as always, for your advice. I love this forum.
-P

[bryanj]

Appologies The info is in the Service Letter file not the Bulletin file and I have not had time to scan those yet but it states:--

When installing the front axle holders, be certain they are positioned with the high mating surface forward. Tighten the forward retaining nut first, drawing the forward mating surface of the axle holder flush against the fork bottom case. Then tighten the rear retaining nut until the axle is clamped securely in place.

Hope that clears it up and when i eventualy finish scannining the 750 parts book i will get onto the Service Letters