Author Topic: CB550 brake piston-what is this ?? (Read 2216 times)

jasonpfm · « **on:** March 26, 2014, 05:20:02 PM »

I just took apart my brake caliper and pulled the piston. Is this mass inside the piston suppose to be there?

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LesterPiglet · « **Reply #1 on:** March 26, 2014, 05:27:22 PM »

No, the piston should be hollow. I never cease to be amazed.

Was the piston inserted the correct way round?

jasonpfm · « **Reply #2 on:** March 26, 2014, 05:32:08 PM »

Yep. I've never seen anything like it! It's solid as a rock!

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jasonpfm · « **Reply #3 on:** March 26, 2014, 05:36:14 PM »

I think a brainiac PO has struck again!

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raymond10078 · « **Reply #4 on:** March 26, 2014, 06:36:49 PM »

Quote from: jasonpfm on March 26, 2014, 05:36:14 PM

Is this mass inside the piston suppose to be there?

Yes. Some caliper pistons are "filled". To convince yourself - just do some searches for NOS parts . . . .

TwoTired · « **Reply #5 on:** March 26, 2014, 07:30:54 PM »

All the stock caliper pistons I've seen are hollow with a plate across the opening (puck side). Yours appears to have had the anti-rust plating removed from the steel plug, allowing the steel to rust. And, it has also been drilled for some unexplained reason.

Lots of shoddy mechanics out there.

Bootlegger56 · « **Reply #6 on:** March 26, 2014, 08:09:06 PM »

The JB Weld monster strikes again!!! LOL

TwoTired · « **Reply #7 on:** March 27, 2014, 02:44:46 AM »

I should add that I would expect this rusting outcome when the caliper is rebuilt without the proper silicone lube to shed the water.

jasonpfm · « **Reply #8 on:** March 27, 2014, 06:12:03 AM »

Needless to say, I should just replace the piston right?

LesterPiglet · « **Reply #9 on:** March 27, 2014, 06:32:47 AM »

I would, even without seeing the pitting on the side.

TwoTired · « **Reply #10 on:** March 27, 2014, 09:56:03 AM »

Quote from: jasonpfm on March 27, 2014, 06:12:03 AM

Needless to say, I should just replace the piston right?

I would, if at all possible. Although it is hidden from view in operation. Who will see the use of shoddy parts? And it may still work well enough to sell off in a few months.

Did I need to say that?

Duanob · « **Reply #11 on:** March 28, 2014, 09:00:37 AM »

I should buy this myself but here you go:

http://www.ebay.com/itm/NEW-OEM-Honda-Brake-Caliper-Piston-Left-CB550-CB700-CX650-GL1100-GL1200-43107-MA-/261404675656?pt=Motorcycles_Parts_Accessories&hash=item3cdceece48&vxp=mtr

decent price for OEM + free shipping. Most used ones go for the same or more. Or the phenolic is the other good option.

Popwood · « **Reply #12 on:** March 28, 2014, 09:53:53 AM »

Hmmm,

I just did a disk brake job on my '75 550K and it sure as heck has a solid piston that doesn't look at all like a modification. The bike is in nearly pristine and original condition as far as I can tell.

There was a bit of pitting on the piston but not too serious. After finding no conclusive opinions about what to do about that I decided to fill them with JB Weld then lightly wet sand back to flush surface starting with 600 grit paper, then 1000 then 1500 grit. Figure the worst than can happen is the JB Weld could break down from brake fluid over time. Also rebuilt the master cylinder. Can't believe the crud that was in there.

LesterPiglet · « **Reply #13 on:** March 28, 2014, 10:12:19 AM »

It depends how bad the pits are.
I did my old forks with Araldite and they lasted until I bought new ones 15 years later.

Duanob · « **Reply #14 on:** March 28, 2014, 10:54:02 AM »

Quote from: Popwood on March 28, 2014, 09:53:53 AM

Hmmm,

I just did a disk brake job on my '75 550K and it sure as heck has a solid piston that doesn't look at all like a modification. The bike is in nearly pristine and original condition as far as I can tell.

There was a bit of pitting on the piston but not too serious. After finding no conclusive opinions about what to do about that I decided to fill them with JB Weld then lightly wet sand back to flush surface starting with 600 grit paper, then 1000 then 1500 grit. Figure the worst than can happen is the JB Weld could break down from brake fluid over time. Also rebuilt the master cylinder. Can't believe the crud that was in there.

Unfortunately you're dealing with your brakes here. Take any risk you wnat but I don't think $35 -$40 for a new brake piston is worth my life.

strynboen · « **Reply #15 on:** March 28, 2014, 11:00:01 AM »

breake fluid eats many types of jb weld..or super glue.

..why takes thances on high risk parts like breakes,, tires,, stering....it dangerus in trafik..so vhy make the odds worse...

Popwood · « **Reply #16 on:** March 28, 2014, 12:10:48 PM »

I did my research here on piston pitting question before doing the JB Weld infill of the few flyspecks of pitting I had. Some respected members said the pitting, if not serious would be tolerated and only lead to a bit of brake drag and more frequent service on the piston seal. I'm not a big risk taker and this repair was nothing like holding mechanical parts under stress together. It will only prolong the service life of the seal. I have no doubt that simply getting on the bike and riding into traffic represents far greater risk. If I start getting premature brake drag, I'll know the JB Weld has failed and install a new piston and ring.

strynboen · « **Reply #17 on:** March 28, 2014, 01:26:12 PM »

yes small pittings make it not leak...or make fail funktion..it most the gluing idea i be a bit vorried abaut.

.if loose .jb.parts can stuck the piston..so it not move..free..
and you sell/give/barrow?? the bike and new ovner/freind,,,who not have same feeling for stuck/free pistons as you..get a hot blocking caliber..locking the fronthveel..

Duanob · « **Reply #18 on:** March 28, 2014, 01:30:37 PM »

Imperfections in the piston surface can allow air into your brake system, then your screwed when you need the brakes the most.

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Author Topic: CB550 brake piston-what is this ?? (Read 2216 times)