Caliper pistons damaged

Hey all! I'm in the process of rebuilding my '83 Seca900 front brake system. When I disassemblied the calipers, I did some damages (most of what you'll see on pictuires) with the pliers I use to pull the pistons out. I think some of these damages are out of the travel area, but some are in and will need to be fixed, if feasable.

I'm concern with this (shallow but easily noticeable with finger nail):



and this (deeper):



There are damages that look bad but that are out of the travel area. I will file them out, but I don't think they could cause any leak, please tell me if i'm wrong. Here is an example:



I'd like to know if JB Weld would fix that?

 

I'd change it. Some of the damage looks like it IS in the sealing area


$35 from len, AKA chacal, AKA XJ4ever.


P.S. Why did you do that?!? 8O :wink:

 

should have done the steam cannon thing

 

I concur. That caliper piston is now a decoration.

Next time you should use shop-air, or a grease gun to remove a stuck caliper piston. Turning it into a steam cannon would be my last choice, even though it is a highly entertaining method.

If the piston isn't stuck you pop it out using the pressure from the brake caliper after the pads are removed.

$37 U.S. is a bargian.

 

Just noticed this line: 8O 8O 8O 8O 8O 8O 8O 8O 8O 8O 8O

 

That isn't a bad question. If it were a fork tube or a low pressure hydraulic ram I'd have no hesitation in filling the gouge with an epoxy and dressing the moving part. I would never suggest that a brake caliper piston be repaired with epoxy, given the likelihood of brake pad contamination if the fix weeps brake fluid. Oily brake pads just don't work.

 

This is what I finally did, because the pliers method wasn't successfull...sometimes I really act like a morron

 

Actually, the pictures show three different pistons. I wanted to show damages of different sizes and patterns.

I checked piston on picture #3 and it really doesn't look like the damage is in the travel area, should I replace it too?

 

The "grease gun trick" always works and isn't dangerous. Plus the stock Yamaha bleed nipple is the same contour as a grease fitting, or close enough anyway.

 

Yamaha brake pistons are made of some sort of metallic looking butter. I swear, you can scratch them with a hard look.

When I rebuilt brakes on my XS I found pistons scored by the previous owner's pliers and already rusting. http://www.hvccycle.net make replacement pistons for old bikes out of stainless steel. Their site is relatively new and doesn't show a lot of product, but they do sell a lot on e-bay. The pistons are something like $25 a piece.

The best part was their service. They sent me a piston for the wrong XS400, didn't know there were multiple kinds. When I told them this they asked me to send them the original and then got me an exact replacement in a week.

 

JP, i'd be skeptical of 25$ brake pistons, seeing as how a foot of stainless bar is 25$ economically something isn't right there. aluminum would be a different story.
http://www.onlinemetals.com/merchant.cf ... &top_cat=0
if the pistons aren't chrome plated, there's a product called TIX SOLDER that i would trust. it melts at 275 deg and could fill the imperfections
http://www.brownells.com/gunsmith-tools ... od108.aspx
or just get new ones

 

Polock, metals cost a lot more when you buy it in small pieces. A 8 foot bar from the supplier you linked is only a bit more than $17 per foot. A full 48' length of stainless stock will make a whole lot of brake pistons, and be more than economical for a small manufacturer to make $25 brake pistons. Most manufacturers don't pay retail prices for their metals anyway.

 

The pistons I got were very nice quality and are functioning fine two years later. Metal was certainly harder than the original.

 

Back to the question at hand:

There is no SAFE way to remedy scratches and pitting of that degree in the area swept by the seals.

I would certainly not bet my life on JBWeld.

Those pistons simply need to be replaced. Sorry.

 

You don't have to feel sorry for that!

I needed to know what is the best way to stay safe, not to save money.

 

All this talk of manufacturing gave me an epiphany!

Make one myself! Dohh!

(I'm pretty sure I know where I can get my hands on a perfect slug of premium stainless, for free!)

Thanks guys.

P.S. Sorry guys, only one. I am not set up to manufacture lots of any kind. I just work in a tool room, I don't own one.

P.P.S. I might just buy one from len though. $37.00 is cheap versus the one to two hrs it would take me to make one.

 

If you look at the I'D of those, it sure looks like that's a tube with a cap on the end

 

Doubtful. Heat distortion from welding would need to be corrected by re-machining the part. Cutting a piston from bar stock takes less time. It would take more time just to do the welding than it would to make one complete piston on a CNC machine. The fewer steps there are the lower the cost to make a part, which is another incentive to just cut the pistons from a slug.

 

I believe the original pistons are forged then machined smooth on the outside. They don't appear to be machined on the inside; and I doubt they're cast.

 

"Bene scio quod iustus amo vestri ya opinio hominis" - k-moe

Laffus outis loudis 8O

 

Don't know how they were made but they are damn soft, that I know.

 

this must work

 

It's a link to Holiday Inn Express...???

 

Does someone know if some other Japanese bikes share the same piston model with the Seca900?

 

Seriously?

You need to learn to use the fiche. May the Fiche be with you, Luke.

Fiche: http://www.yamahapartshouse.com/oempart ... ycle/parts

Select bike, look up part. Highlight and "copy" part number.

Return to model selection page. On the right, where it says "Search by Part Number" "paste" your number in and click "search."

When the result comes up, click the "where used" link.

In your case, the results are all the way from your bike to the 2009 V-Star Silverado rear brake caliper. It's a whole freaking page of other bikes using that piston, which is of course still available from Yamaha for $70 USD and change.

 

Thanks a lot Fitz!

 

I get it. 8O

 

+1

 

That's awesome.

I often make parts that many people think I'm crazy for making, and there's no way I'd take on that job. You'd have to pick the right grade of material to even turn it. Then there's the finish and the tolerance... It's a ground surface on the OD, both for tolerance and for sealing finish. You're going to rough turn in a lathe and then finish in the grinder?

Far be it for me to tell you not to, but I betcha it looks easier than it really is. And at less than forty bucks, unless there's some reason why the part you make yourself is better in some way than what you could just buy? No way!

 

Some cars have plastic pistons. I could probably use a chunk of Delrin or some such piece of plastic, after doing some research of course.

Bakelite comes to mind.

I'm sure I could make one at least as well thought out and finished as some of the better aftermarket pistons out there.

I'm from SE Michigan, we know how to make shit. 8)

 

some parts
we've been making, the top clamp we made in the spring.
the bunch of little things is a internal valve for a AutoCocker paint ball gun 100$. if you guys want one i'll give you a discount, 95$

 

You can't turn stainless? :roll:

 

Beautiful stuff Polock!

 

you can turn stainless but there's a bunch of different kinds, some not too bad some really bad.
stainless "work hardens" that means you can't take small passes till it's right.
you either dial it to the right size or throw it away, that's why those are ground like Rice_burnarr said.
if you really want to make some, do aluminum and send it to get anodized

 

I was being sarcastic.

Aluminum is a good thought too.

 

Use the sarcasm font.

 

Sure you can. Done all the time. If you pick the right grade. :roll:

Regardless of the material, I'm just saying it sounds simple. Maybe simpler than it really is in practice.

Don't let me dampen your spirits though. No harm in you trying!

 

Back in the Mesolithic era, I was our teams airsmith. I've made lots and lots of paintball parts. No pics though because cameras were yet to be invented.

Wonder if we've shot at eachother in the long distant past!

 

Back in the day I was the ref with a marker. You took your hit or got hit again.
Ref color in the back ,😆

 

Then I'm positive we've shot at eachother in the past!

Hahaha!! J/K!

 

I've done my fair share of disproving naysayers in my life for sure, mainly by reasoning to myself, who the hell are you.

You seem so sure of yourself.

So am I. 8)

 

I don't "get" the link to Holiday Inn Express. I am a little slow.
TR

 

It's the series of commercials they run on TV.

Some guy who is not appropriately trained in the art is doing something that he otherwise should not be doing. He succeeds and when question about it he always says "No, I'm no (whatever), but I did stay in a Holiday Inn Express last night."

The concept is that making the decision to stay at a Holiday Inn is such a wise decision that you must be incredibly smart to do so. And the implication is that someone who is that darn smart could do just about anything.

Like solving Korman's Enigma.
Or flying a helicopter.
Or stopping a meltdown at a nuclear reactor.

Here's a couple:
https://www.youtube.com/watch?v=7jo_x7ecIFg
or
https://www.youtube.com/watch?v=8dOHEw8izno