Cleaning calipers

gjr

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I'm rebuilding the calipers on an '82 Honda. I'm planning to use denatured alcohol for cleaning the bores. What do you think of using something like scotchbrite in there too ?

Thanks

Greg
 

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That might depend on what grade pad and why you need to,does the seal groove have corrosion or build up of some sort.
Bikes from locations that put salt on the roads seem to be the worst for the calipers getting crusty,depending on the severity maybe masking and a low buck (You tube) soda blaster might be easier.
 
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I have cleaned Honda calipers many a time with fine grade emery cloth in order to remove that fine white powder caused by road salt.
Denatured alcohol or methylated spirits is fine to use as a cleaning agent, getting the grove for the piston dust/ ring rubber seal clean is the biggest problem.
I now use a high melting point synthetic grease and avoid that copper grease on the calipers-this will cut through the dust seal within a month-don’t’ ask me how I know.
 

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I'm not convinced using a flex hone on a caliper bore is a good idea. :?
That section seems to be about master cylinders.
 

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A very long drawn out link.
Do we have to guess,no I wouldn't touch a seal groove with a brass bristle brush either (especially on a small bore caliper)

If you live in a location where they put salt on the road you can do one of two things.
A. You can be ignorant wait until the corrosion has set in then try and fix it.
Of course corrosion often means the loss of material or the surface is compromised,sometimes to a point of end of serviceability (The seal groove and dust seal area are corroded beyond repair)
The same person would no doubt when pads had worn simply push the piston back into the body without cleaning the area where the seal contacts.

B. You check brake caliper condition,clean if necessary and change the fluid yearly,that would include any other items on a motorcycle that might be affected by salt or any other detrimental substance.

If the groove is only crusty a white scotchbrite soaked in white spirit would normally do it,if it takes more than that it might already be to late.
Fail that a simple length of small bore tube with a slit in it, air duster snout into the slit and up the tube 50mm or so,the other end into a box of baking soda,low pressure on a compressor if you have it and that will remove any deposit with no harm to the parent metal.

 

gjr

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Thanks guys. The low tech soda blaster looks like a handy thing to have around. The XJ site is pretty far into rebuilding brakes. I never imagined that anyone even remembered those bikes. Although, I'm working on an '82 GL500...

Greg
 
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Not sure what Dr Who is on about with his "do we have to guess" comment :lol:

Anyway there is no issue with using a brass bristle brush in the groove where the seal goes. I and many others on that forum have used it many times with no ill effect. There is no need for a mirror finish where the outer edge of a seal sits even IF there was scratching occurring. The deposits in those grooves can be extremely stubborn and you need to ensure you get every last bit out....

Oh and a big bore 82 Honda caliper is nothing like a Tokico caliper so unsure why that was featured?
 

gjr

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Adrian1 said:
Oh and a big bore 82 Honda caliper is nothing like a Tokico caliper so unsure why that was featured?
These are the later two piston calipers, but I hear you about cleaning the crud out of the oring grooves. Now I just have to bleed the damn things.

Greg
 
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Easy, obtain an Gunson Eezibleed kit from a car shop, get hold of a pipe that goes over your caliper bleed nozzle and somehow connect it up to the Eezibleed pipe, (I use a Lucas bullet connector! & lockwire the pipes )
Connect it up to a tyre with 20PSI and bleed up into the master cylinder. :shock: :)

http://www.halfords.com/webapp/wcs/stor ... yId_255216

Tighten bleed nipple, and use a normal jam jar and pipe to lower brake fluid in m/cylinder to finish.
 
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The Gunsons Easibleed is absolutely the most cost effective tool in my shed.

The seal groove merely locates the seal surely. Once correctly fitted the radial pressure from the piston and the hydraulic pressure from the fluid working axially will prevent any leakage. The elasticity of the polymer should allow conformity to the working surfaces. Remember, the seal deforms in use, its "memory" is what retracts it. It will only slide a tiny amount as the pads wear and the additional movement of the piston overcomes the hysteris of the polymer.
A scored/corroded piston is something else.
Unless your brakes are a lot different from Brembos.

Make yourself some pistons out of stainless. Fill the gap between the seal and shitshield with silicone grease and it will last for years.
The above Easibleed will make annual fluid changes painless.
 
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