Another front brake (& fork) thread

[pullshocks]

After my experience with the kid running across the street in front of me, I have become concerned about the poor stopping power of the front brakes. 

I took a look at the calipers this weekend and did not like what I saw.  Sliders not sliding, damaged slider boots, uneven pad wear, and pads appear oily.   I greased the sliders and tried to clean the oiliness with brake kleen.  A test ride showed little if any improvement, so it's time to stop the fork oil leak and go through the brakes. 

So its time to order up some parts --new pads, braided brake lines, new slider boots, fork seals, and roller bearing head set (as long as the fork is coming apart I might as well install that too).  When it comes to the caliper pistons and seals, I am a little confused about what parts I need, and whether the caliper pistons actually need to be replaced or if just the seals can be replaced.  Also, are the seals the same as the O rings?

Here is the parts diagram from YSPPart.com



The tag numbers seem to be a little goofed up, can anybody clear up what I need to order?



8  SKU: 11H-25919-00-00 SUPPORT, PAD 1 $7.12 

9  SKU: 4X8-W0057-00-00  PISTON ASS'Y, CALIPER 1 $43.43 


Thanks,

[Walt_M.]

When I rebuilt mine 5 yrs ago the rebuild kits were available from Yamaha and contained the piston and seals. I needed 2 caliper kits and a mastercylinder kit. I think it was a bit over $100 for everything. My original pistons were probably ok to reuse but I don't think they sell the seals separately.

[h2olawyer]

Part # 8 - the pad support is no longer available.  The pads are #s 6 & 15.  The diagram you have is for an 83 - if you have an 82, some part #s are different.  You might want to go with Ferodo, EBC or sbs brake pads.  They're all probably better than the OEM & cost less as well.

The seals & piston are sold as a set.  Normal O rings will not work.  These seals are squared, not round in profile.  Not sure if Old Bike Barn sells the seals alone or not.  Might be worth checking out.

For an 83, plan on spending $125 or more for piston, seals & pads.  I built a brake line for my 83 system using Goodridge hoses & fittings.  Cost me about $140 several years ago.  An 82 would be much less $$.

H₂O

[joevacc]

I got the seal and piston kits from Yamaha in January.  I think I paid under $60.00.  I have an '82.  Don't know about the '83's.

[kwells]

also, Pyramid makes pads

[Tiger]

 :) The Brake pads, tapered head bearings and fork seals you can get from Pyramid, (PKN Trading), on eBay... 8)

The S.S. Braided brake line's from Galfer, (again on eBay trading as Sum of all Parts). I just bought a set of '83's for $94.00'ish + shipping...cheaper for '82's.

The brake slider boot's and caliper rebuild kit(s) or piston seals are available at your Yamaha dealer...arm 'n leg + your first born!!!  :D :D :D :D :D :D... ;) The pistons can be reused as long as they are not pitted/damaged... ;)

               8).......TIGER....... 8)

[pullshocks]

As always, thanks for the tips.  I remembered the PO gave me a set of EBC pads and I found another set on ebay for 9.99, plus the pyramid seals and bearings are cheaper than the ones Dennis Kirk sells, so that takes some of the pain out of the high price of the OEM brake parts.  Fiat Doctor is setting me up with some SS brake lines.

I hope this goes smoother than my last repair......

[pullshocks]

Well, I have the front brake calipers cleaned out, new pistons and seals, new boots, braided stainless steel lines, and the bubbles painstakingly bled out (mountain bike experience helps, even though Hayes MTB brakes are bled backwards)

The brake lever is firm

No time for a test ride, but on the left caliper I can see a noticeable pad movement as the brake is applied and released.  Pad movement is not visible on the right caliper although the pads did push up against the rotor.  Normal?  If not, any idea what I might have done wrong?

[Brian Moffet]

Is there rubbing when you spin the wheel?  If not, don't worry about it.  As the pads wear, they will move to a steady state just above the disks, and the movement will be very small.

Brian

[thisandthat]

I'm in the middle of trying to get my brakes back in working working order. Is there a newer setup that fits on this bike? Because I'm realizing it be cheaper to buy new calibers then to rebuild these old ones? On that note, is there a company that has rebuild ones? One of the reasons I"m asking is I bough 11-20 and 12-21 and cost me over 30 bucks, and after a new brake line, new pads, possibly a new disk, Its going to be a lot, and I'm still left with a stock braking system from the 80s.

[Brian Moffet]

If you bought a new one, wouldn't you still need to rebuild it (if it was used?) and it would still cost more?

I know someone has put a newer system on, manufactured a bracket for it and everything.

Brian

[thisandthat]

Well I'm pretty new to fixing bikes, but a set(two) of rebuild calibers for my car costs less then...$100, its its just as old as my bike, now I'm paying $30 for a pair of rubber boots. I was thinking that that bold pattern and the angle for the caliber can't be unique, and perhaps theres a newer setup I can buy.

[supervision]

 pullshocks, once the pads take up slack next to the disk, they don't move much from their. When the brakes are applyed the square O ring twists itself, slightly,  in the bore of the caliper, so as soon as the preasure is released, the pads don't drag.   

[pullshocks]

Tried it out.  Braking is much stronger.  But when I go home, the left rotor was warm, and the right one was cool.  So I figure the right hand caliper is not working up to par.  The good news is braking should improve still further when I get this worked out.

Piston sticking?  Crud in the line?  Any other likely culprits?

Short of pulling it back off and dismantling again, anything I can do?  Maybe I'll try pushing the piston back in...see if that frees it up

[Tiger]

...the left rotor was warm, and the right one was cool.

:) I would bleed them again, starting at the left one... ;)

                    8).......TIGER....... 8)

[QBS]

Why start with the left one?  It shows correct performance. The right one shows under performance.

[Tiger]

Why start with the left one?  It shows correct performance. The right one shows under performance.

Its the furthest from the master cylinder...

           8).......TIGER....... 8)

[fiat-doctor]

It's not the bleeding!  Hydraulic systems have equal pressure in ALL lines... if there is air somewhere, the pressure will be low at both calipers.  Thats why vehicles use hydraulic brake systems, not cables.

Likely a difference in the freedom of movement of one caliper or caliper piston compared to the other.

If you take a ride for a while and don't use the front brake, then stop by using the rear.... if one rotor is warm and the other cool, the warm one is dragging.
If you take a ride for a while and use the front brake moderately then stop and check the rotors.... if one is warm and the other cool, the cool one is not working properly.

Steve

[pullshocks]

FD, what you say makes sense, but I did get some fine bubbles out of the right (weak) caliper, and none out of the strong caliper.  Both rotors were nice and warm tonight.

Could it be that the small openings in the banjos act like critical orifices, allowing equal volumes of fluid to pass into each line without allowing the pressure to equalize? 

Actually it could be something else, too-- before I bled the brakes I looked at them in better light, and the piston was moving, but the pads had only the tiniest amount of movement.  The pad was not quite square to the piston,and seemed to be hanging up.  I loosened the retainer bolt and wiggled it around a little bit and now it the piston & pad seem to be moving in harmony.

Either way, the brakes are working great now.  A very worthwhile upgrade.

FD, do you still want the old piston seals?  If so, PM me, as I seem to have lost your phone #