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Really? Usually all I find is generic caliper grease.
I'm talking about what lube to use for the piston/seal.
99% of the pro mechanics I know out there use brake fluid to lube the piston seal, not grease. Grease is for the slide pins external to the caliper and won't contaminate the brake fluid - which your bike doesn't have because it uses that swing caliper bracket. IIRC the bracket has a zerk fitting on it so whatever chassis grease you have is fine since it doesn't get hot like the caliper.

you don't need to buy a "new" caliper unless you want to do a brake upgrade (and if you do, I know someone that is the US beringer dealer with a kit for cb750's but it's pricy). Just buy a new piston (phenolic is best) and seal and rebuild your old caliper. Almost all cb750s have a sticking caliper from sitting because the chrome steel one rusts and hangs up in the bore.

While you are in there futzing with the brakes - order stainless braided lines - way better than stock rubber in that they won't expand and get spongy.
 

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Do the forks at the same time. Nothing is worse than oiling your fresh brake pads when the forks start bottoming.
 

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i use pbr rubber grease that is castor oil based, made for the job it says.

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Much better than brake fluid, especially if the cylinder or caliper are going to sit for a while. Not hygroscopic like brake fluid, so bores and pistons won’t fester. Slipperier than fluid, so less chance for the Newby damaging any seals. Some of will stay in the seal lands which slow down any future corrosion. Used sparingly, it won’t screw anything up. Most rebuild kits I have bought come with a small container or you can buy it on EBay. Nickel anti seize works for pins etc, copper will do, but easier to just buy nickel and then you can use it on high temp things like exhaust studs.
 

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That dow corning high vacuum grease is the only thing that will stop the sohc4 caliper from squeeling. You just use on the back of the primary pad between the pad and the piston. Those primitive sohc4 calipers will probably squeel anyway. I don't even try to stop them anymore. I got a few riding buddies into the sohc4's and it is always the same when we ride together...squeel them stone age sohc4 calipers with pride.
 

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That dow corning high vacuum grease is the only thing that will stop the sohc4 caliper from squeeling. You just use on the back of the primary pad between the pad and the piston. Those primitive sohc4 calipers will probably squeel anyway. I don't even try to stop them anymore. I got a few riding buddies into the sohc4's and it is always the same when we ride together...squeel them stone age sohc4 calipers with pride.
Molykote M77 should work as well. On the auto side, OEM Honda pads come with a little tube of M77. It’s expensive IIRC but worked and lasted the longest. I wonder if (similar to the cars) you added a shim between the pad and piston... it might quite things down longer. M77 or your vacuum grease on both sides of the shim would help prevent it.
 

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Really? Usually all I find is generic caliper grease.
I'm talking about what lube to use for the piston/seal.
You are thinking too much like a car guy, have you replaced the wheel bearings yet? The wheel bearings are cheap crap deep grove magneto type roller bearings and are available at any decent bearing supply shop for about 7 bucks. If the wheel bearings are not perfect your brakes will never be right.

There are not a lot of sliding surfaces on your antiquated round pad Honda CB brakes. They aren't even designed well in that they have round pads and a single piston calliper that pivots on a door hinge type arm which is truly archaic and accounts for why they never really worked well.

 

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Discussion Starter #29 (Edited)
Thanks for the input fellas!

I got the job done this weekend. I ended up just using brake fluid for the piston/seal and used some permatex brake lube behind the pad. I'm glad I bought a new caliper kit because the old one was seized as f*ck. I flushed out the master cylinder too and there was so much gunk/rust in there it looked like chocolate milk. Although the piston is still stuck in the old one, the caliper itself looks like its in decent shape so I'll probably end up rebuilding it and keeping it as a spare or something. I also got one of those little 1 way bleeder valves which made bleeding the brakes soooooo easy too. I was honestly surprised at how simple it was.

Anyways, I rode her for the first time too and let me tell you, I'm hooked. This is going to be too much fun. I didn't get any pictures, but I'm just stoked I can actually ride it now. Or even move it around so I'm not blocking my other babe in the garage ;) ;) Me and my dad share a garage so space is limited Lol.


Rebuilding the forks is next on the list for sure. I wiped them down good before I left and when I got back (barely 30 minutes later) they were drenched.
 

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I think you have made a good choice for your first motorcycle. Properly maintained, it will give you a lot of experience of both riding and spanner work. If you in some two years or more want another bike, you'll know much better what to buy. I started my motorcycling on an early Harley flathead. After three years I bought a thirty year younger Norton.
On brakes. Compared to the drum brake it replaced, the Honda disc brake is a huge improvement.
 

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Discussion Starter #31 (Edited)
Got a few things knocked off the list this week!
- New fork seals
- New master cylinder
- Superbike handlebars 8) 8)

I'll tell you what though, getting the old fork seals out was a pain in the ass. I tried all the little tricks and nothing worked until I let them soak in PB Blaster over night. Even then, I had to buy a seal puller and get out my blowtorch.

Anyways, she's back together and ready to go!


 

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Fork seals are so easy to remove if the stanchion tubes just have a bushing on them.
Anything that doesn't is an exercise in planned obsolescence and cheap mass production.
 

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Discussion Starter #33
... Those primitive sohc4 calipers will probably squeel anyway. I don't even try to stop them anymore. I got a few riding buddies into the sohc4's and it is always the same when we ride together...squeel them stone age sohc4 calipers with pride.
I've been riding the bike a lot and anytime the brakes squeal I think of this comment Lol.

She did good at keeping up with my buddies and their newer bikes this past weekend! Although I found out the clutch slips whenever you get on it hard. :p
 

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.. the clutch slips whenever you get on it hard.
Is an old bike, are you using regular motor oil or some modern synthetic with friction modifier stuff in it?
If your oil is good, pull the clutch all apart, clean it, inspect it an bolt it back up, will likely be fine. If the clutch has signs of having run burning hot :/ emery the steels and start replacing friction discs.


Brake problem is the result of the round pads and the door hinge brake calliper :/ that disc was only marginally better then a good drum brake when they were first introduced.
Be careful trying to keep up to the newer bikes, remember you are riding a freight train with marginal brakes and tires or the bike will remind you when you come into a corner a little too hot.
 

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Be careful trying to keep up to the newer bikes, remember you are riding a freight train with marginal brakes and tires or the bike will remind you when you come into a corner a little too hot.
Yep, or baling into the back of a buddy under braking will pretty much assure you the dunce cap. Add a passenger and it's a different bike again.
 

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Should add that some investment in new suspension components would help with handling, give you more control under hard braking. What's on it for tires, date stamp?
 
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