Author Topic: brakes  (Read 2478 times)

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mongeon

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brakes
« on: July 01, 2005, 03:37:09 PM »
I had to remove the front tire to work on the forks.  I took the brake off.  When I did this, the piston came out.  I pushed it back in, and put the brake back on.  When I squeezed the brake, the pads tightened, and remained so.  How do I get it to work properly again?  Is it possible the piston was pushed in slightly crooked?  It is a 74 550.

Thanks,
Chris

Buffo

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Re: brakes
« Reply #1 on: July 01, 2005, 04:08:15 PM »
my recomendation is:

6 ounces of Ocean Spray Cranberry juice
2 Shots of Skyy Vodka
1 big slice of lime (squeezed)
Pour over large glass of ice

Don

Offline Bob Wessner

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Re: brakes
« Reply #2 on: July 01, 2005, 04:11:30 PM »
Chris,

It's quite possible. Did any fluid come out when the piston fell out? I think, if the rest of the brake system is known to be in good shape, minimally you need to bleed it. If it hasn't been changed in two years, you should drain the system and put in new fluid.
We'll all be someone else's PO some day.

mongeon

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Re: brakes
« Reply #3 on: July 01, 2005, 04:22:51 PM »
The piston didn't fall out, it just came out further than usual.  There was no brake fluid leaking.  It was very difficult to get the piston back in.  I had to use a C clamp.  I was hoping I wouldn't have to drain it and take the whole thing apart.  It may be my only option.

Offline oldbiker

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Re: brakes
« Reply #4 on: July 02, 2005, 01:11:27 AM »
Make sure the fluid return hole in the master cylinder is clear.

mongeon

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Re: brakes
« Reply #5 on: July 02, 2005, 01:24:43 PM »
Any suggestions on when I should replace the brake piston?  There are some rust spots and pits on it, but it is not terrible.

Offline mcpuffett

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Re: brakes
« Reply #6 on: July 02, 2005, 01:35:28 PM »
hi mongeon, any chance of any photo's please? may help us to help you  ;)  mick.
Honda CB750 KO 1970,   Honda VTX 1300 2006, Lancaster England.

Offline Bob Wessner

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Re: brakes
« Reply #7 on: July 02, 2005, 02:02:42 PM »
The rust spots and pits will become leaks around the seal, you really should replace the piston. This is not a system you want to have any questions about.
We'll all be someone else's PO some day.

mongeon

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Re: brakes
« Reply #8 on: July 02, 2005, 05:19:02 PM »
Here is a pic of the piston.  This is the worst of it, and there is a little more on the other side.
« Last Edit: June 25, 2007, 06:39:52 AM by Glenn Stauffer »

Offline Bob Wessner

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Re: brakes
« Reply #9 on: July 02, 2005, 06:25:50 PM »
Bad, fure sure, replace. Sorry, you were probably hoping for a different answer.
We'll all be someone else's PO some day.

Offline jotor

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Re: brakes
« Reply #10 on: July 04, 2005, 07:56:30 AM »
Someone on eBay last week was selling a phenolic piston from a Lincoln LS8 as a replacement for the Honda piston.  It may have been modified.  Anyone know anything more about this?  I've been thinking about a trip to NAPA with Honda piston in hand.
I'd rather ride a Yamaha than eat worms.


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Offline kyre

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Re: brakes
« Reply #11 on: July 05, 2005, 04:27:45 PM »
CB400F / 466 Build Thread (currently in progress)
http://forums.sohc4.net/index.php?topic=105027.0

mongeon

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Re: brakes
« Reply #12 on: July 09, 2005, 02:12:21 PM »
I got a new brake piston, and cleaned out the housing for the seal.  The piston popped right in, without excessive force.  I am still having problems getting it to retract and loosen up so the wheel can spin.  Should I just keep adjusting the stationary pad until the piston finds it's happy place?  Is there something I have done wrong?  There are probably a few air bubbles still in the line, which I am hoping will work their way out if I let it sit for a day or two.

Thanks again,
Chris

Offline Bodi

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Re: brakes
« Reply #13 on: July 09, 2005, 04:03:17 PM »
Well, bubbles are unlikely to work themselves out. Bubbles can cause this non-release problem.
The piston didn't just "fall out", someone pumped the brake lever while the disc was out.
You should be able to work bubbles up by loosening the caliper bolts and pumping the piston out slowly, waiting an hour or so, then tightening the bolts again and forcing the piston back in - pumping fluid and bubbles back up to the reservoir. A few repeats should do it. The fluid will squirt up pretty nicely when tightening, be careful. Don't pump the master reservoir dry and cause more air to enter.