Stuck RD Brake Piston

2_DONE_THE_TON

2_DONE_THE_TON

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Since i'm restoring my brake systems on my RD 1978 i tried to remove the brake piston.

i put air pressure on the opening of the banjo bolt (the deaeration screw was closed,brake pads removed).

didnt move a bit.i saw people doing the removal just by connecting the main brake cylinder putting liquid in having the pads removed.

thanks for the help in advance!


question 2:what do you guys normally buy and put in when you take apart the brakes,dust cap and o ring?or should i just clean them with DOT and leave them....little helpless here.

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Re: Stuck RD Brake Caliper

i little confused....is the caliper not breaking into two halves? or is the piston stuck? either way i always use a grease gun and it has never let me down.
 
AW: Re: Stuck RD Brake Caliper

raptormeat said:
i little confused....is the caliper not breaking into two halves? or is the piston stuck? either way i always use a grease gun and it has never let me down.
Click to expand...

the caliper is actually casted in one piece.
i mean the piston...sorry.
where do you put the grease gun to?to the dearation screw?

i dobt have one so ill rather try first with the main brake cyl.
 
Re: Stuck RD Brake Caliper

I would first try and remove the piston with brake fluid going through the normal motions with the brake lever. If that doesn't work remove the fluid feed line and install an applicable fitting to the caliper and grease gun and use grease to push the piston out. When ever I disassemble a caliper I always rebuild it with a new seal kit (piston seal, gallows dust seal, slide rubber bushings,etc.), And use anti seize on the bolts and caliper grease on the sliders.
 
AW: Stuck RD Brake Piston

so.....i made it.

handpumped the piston out of its place...wasnt that dirty inside.cleaned everything,removed the paint (gets renewed).

the round surface of the brake element is pretty crooked,i dunno what the preowner did to it...
should i be worried?the brake had no leaks since i bought it.

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i figured out what a new seal kit costs in europe...50 euros for each brake...so im asking you guys if i can reuse the rubber parts and the seal?
the rubber shaft has on the outside a little dooky surface.
is it safe to keep them?

rubber shaft

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backside

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seal

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thanks for your help!
 
If the calliper wasn't leaking, you can re-use the seals (although the dust seals look pretty bad in your pics).


The main thing is to get all the corrosion out of the channels where the seals sit in the calliper body. Use a pick tool or a bent piece of wire to scrape it all out. The corrosion builds up over time and pushes the seal against the piston - which freezes it up. And that's why the outside of the seal looks beaten up - it's been sitting on the corrosion.


Also, how is the piston? If there's pitting, it needs to be replaced.
 
AW: Stuck RD Brake Piston

thanks hillsy!

is there some kind of fluid to solute the grime/rust in the ledge for the seal?i tried it with a smooth dremel piece and there is still grime in there.

the pistons have little to no pitting.gonna post a detailed pic later.

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what do you think about the rugged edges of the 'piston container' on the pic below i dont think its a big deal as long it doesnt hurt the dust seal structure.

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As long as the piston moves freely inside the caliper it's OK.

Slide the piston back in the caliper with the seals out to check. It should move freely....but not be "sloppy" in the bore.
 
Can you get just the piston seals without the dust seals? If the dust seals are ok, then re-using them is fine. yours look questionable though. With things like brakes I tend to err on the side of safety every time... which will cost you more, seals for your piston or a trip to hospital when your brakes fail? I'll assume that the RD used piston seals also common to other bikes- XS, etc. They may still be in production.

EDIT: I found on bikebandit.com under OEM parts there is a seal kit available for $44 USD. Yamaha is still making the parts. Link below:

http://www.bikebandit.com/houseofmotorcycles/1978-yamaha-rd400e/o/m7515#sch215562
 
runmikeyrun said:
Can you get just the piston seals without the dust seals? If the dust seals are ok, then re-using them is fine. yours look questionable though. With things like brakes I tend to err on the side of safety every time... which will cost you more, seals for your piston or a trip to hospital when your brakes fail? I'll assume that the RD used piston seals also common to other bikes- XS, etc. They may still be in production.

EDIT: I found on bikebandit.com under OEM parts there is a seal kit available for $44 USD. Yamaha is still making the parts. Link below:

http://www.bikebandit.com/houseofmotorcycles/1978-yamaha-rd400e/o/m7515#sch215562
Click to expand...

thanks for your support!

yesterday i want to a local brake specialist.he told me that i can totally reuse the dust seal and the ring seal in the piston,he said that the dust seal is just for keeping them dirt coming in the brake.
im a little confused now....wont the brake lose all its pressure/fluid if the dust seal breaks?

unfortunately its really hard to buy any of these parts in single...but i think im gonna go with this one...i live in europe.

http://www.ebay.com/itm/YAMAHA-RD400-RD250-RD-400-250-BRAKE-CALIPER-SEAL-KIT-/271194698833?pt=UK_Motorcycle_Parts_13&hash=item3f2476b451#ht_978wt_916

any experiences on yambits?

after cheikcing out the diagram of my brake i realized that the preowner did not use a brake pad retainer...the parts number 8 and 9,9 is the retainer are not avaible anymore and really really hard to find on ebay or somewhere else.



is it safe to ride without these retainers?the pads are floating so i guess not...
any of you know how to get these clips?
 

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