Ross’ 1975 CB750

[Galactica]

Would anyone who has machining skills be able to help repair the bleeder screw seat?

[Hawkeye]

I would need a lot more detail to be able to answer that question. Like any valve seat, there needs to be enough material on both sides to make a good match.

[Galactica]

I tried to scrape out the crud.  With no success.  I may even have made it worse.

[Galactica]

So I sent pictures to Dave Silver Spares along with my complaint/concerns about the caliper I got from them.  Their response was that it was fine, and basically that I don’t know what I’m doing.  They may be right, but  I’ve bled brakes many times before and never had this hard of a time. 

[Steve G.]

  English POME bastards!!!

[Galactica]

I’m making a bit of progress on the front brake.  Now at least it pumps up with a few pulls on the lever.  But after a short time it’s squishy again.  Like I said…progress?

[Twisted_Twin]

Ok, so you might need to borrow some tools for this but it's worked every time for me.
I learned about it while bleeding a Ford hydraulic clutch that had no bleeder screws. This is the way that Ford recommended bleeding the system.

Get a mityvac hand vacuum pump and a rubber stopper or some sort of cap that fits the master cylinder tightly and lets you connect the mityvac to the cap. You may have to make something. Mine is a rubber stopper with a piece of metal tubing in it.

Fill the system with brake fluid and leave a little space at the top. Put the cap on and connect the vacuum pump.

Pull vacuum on the system for about 30 seconds and release slowly. Repeat about a half dozen times and check to see if the system builds pressure.

I don't totally understand how it works but it has worked every time I've needed to use it. I think the vacuum helps the bubbles expand and work their way out of the system.

I've never had to use it on a motorcycle brake system but I can't see why it wouldn't work, or at least be worth trying.

[Galactica]

I tried to scrape out the crud.  With no success.  I may even have made it worse.

So I asked Peter to see if he could clean up the bleader screw seat.  I didn’t really hold out much hope.  But he managed to do it.  Thanks very much Peter.  I’m 100% sure I have all of the air out of the system now, so rather than put the repaired caliper back on just now, I’ll run it’s is for a bit.  I hate brakes and brake fluid.

[Galactica]

To be fair, brakes on 70's Hondas are pretty poor.

Maybe it's rotor / pad finish that's doing it.

Even the brakes on my Stelvio are awful until they've bedded in after a few miles.

Ya, I think these brakes are just poor.  I’m 100% sure I have all of the air out of the system.  I’ve put a spacer in the lever to take up all of the space between the lever and the master cylinder piston.  The free play had been around 5/8”, now it’s about 1/16”.  The lever now, is firm and leaves room for fingers between the lever and the grip.  Still doesn’t stop the bike as quick as I’d like but it is what it is.  Maybe I’ve just gotten too used to the stopping power of my Tracer900.

[Galactica]

A couple of days ago I took off the swing arm again.  When I initially took it off for cleaning and bushing replacement, I had inadvertently pressure washed out one of the felt dust washers.  Got some new ones in my latest parts orders, so I replaced them.  

Also in the parts order was a new rear wheel bearing retaining ring and removal tool.  In the past, the rear hub at the retaining ring has been punched so that the ring cannot back out on its own.  The bearings seem fine, but at the least I wanted to squooge in some new grease.  Had to use much force to begin the unscrew the retaining ring.  Immediately there was coils of aluminum coming off of the threads.  So I stopped and re-tightened it.  Leave well enough alone I guess until/if the bearings fail.  

The front wheel bearing retaining ring has been significantly damaged by a previous owner using a hammer and chisel/screwdriver, and punched several times.  I purchased a new ring and removal tool for this as well.  The front bearings feel fine as well, but I’d wanted to at least squooge in some new grease there as well.  But I’ll leave alone as well for now.

Sorry I didn’t get any pictures.  Would have helped explain things better.

Cheers,
Ross

[Runningdog]

My CB350 has the same ring holding the bearings on, by the time I got the front one off, I had to obtain another wheel, which was when I learned about respoking.

[kilowop]

Regarding brakes, was wondering IF you had bothered to sand the pads.  If they are original, good chance they have hardened and "MAYBE" sanding them with coarse grit "MAY" allow them to grip better.  Just a thought as it has worked for me in the past.  I usually buff up New pads a bit as well before installing them.
Good Luck with the resurrection.

[Twisted_Twin]

For the grease thing, you can buy an attachment for your grease gun that is a zerk nipple with a hypodermic needle on it.

Works great for balljoints, etc that don't have a zerk fitting. Just push it under the edge of the boot or even poke a hole and pump some grease in there.

Would probably work to go under the seals in the bearing too.

[Galactica]

Regarding brakes, was wondering IF you had bothered to sand the pads.  If they are original, good chance they have hardened and "MAYBE" sanding them with coarse grit "MAY" allow them to grip better.  Just a thought as it has worked for me in the past.  I usually buff up New pads a bit as well before installing them.
Good Luck with the resurrection.

Ya, I scuffed the pads with course emery cloth.  Brake bits are all new top to bottom excepting the master cylinder body and switch splitter. 

[Galactica]

Has anyone done back to back comparison between new rubber brake hoses and braided ones ?