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Rear Brake Caliper Overhaul - Alternative Piston Removal Methods?


wawasonqo

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Hi Folks,

 

Hoping I don't have to do this but ...

 

Looking at the Parts Fiche diagram doesn't show any differences but the pictures of the Caliper Piston Seals, shown on the Online Stores and page 15-40 of the service manual, indicate they are.

 

Just wish to confirm the difference is correct?

 

https://www.davidsilverspares.co.uk/parts/by-part-number/partnumber_06451MZ2405/

 

https://www.davidsilverspares.co.uk/parts/by-part-number/partnumber_06431MA3405/

 

https://www.davidsilverspares.co.uk/parts/by-part-number/partnumber_06431MA3405P/


Is there another way to get the pistons out than the method described at the top of page 15-39 of the service manual?

 

Thanks!

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Would be helpful if you post "page 15-40 of the service manual," and  "the method described at the top of page 15-39 of the service manual"

 

Or do you expect folks to search for it to help you?:laugh:

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There are kits available - Honda VFR 800 Fi-1 01 Parts at Wemoto - The UK's No.1 On-Line Motorcycle Parts Retailer - I used these guys for my Fi-1 brake overhaul

 

If yr servicing the brakes, why not replace the brake hoses with braided lines? I'd recommend Galfer!

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I assume you mean this method below using air pressure.

 

Yes, there are tools you can get like pliers in reverse that you pull the piston out with. I'm sure someone has another method though.

1.jpg

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Agree with Skids, but the air pressure method is the most direct and efficient. Some very old school guys use a grease gun, but is way too messy, IMO.

 

Also, what "parts fische" are you using, as all the ones I see shows the piston sizes with the part numbers. So that would be confirmation of sizes for the corresponding seals for each.

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Before using the compressed air you can remove the pads and pump the brakes to get the pistons started. When you use the compressed air, keep your fingers out of the way. The pistons will pop out with an alarming quickness!

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11 hours ago, Skids said:

I assume you mean this method below using air pressure.

 

Yes, there are tools you can get like pliers in reverse that you pull the piston out with. I'm sure someone has another method though.

@VeeEffArah

 

Yep.

 

Could a wooden dowel and a rubber headed hammer be used do you think?

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9 hours ago, VeeEffArah said:

Also, what "parts fische" are you using, as all the ones I see shows the piston sizes with the part numbers. So that would be confirmation of sizes for the corresponding seals for each.

I was referring to the images shown on the PartZilla website and in the SabMag/VFR List Microfiche & Manuals Electronic Reader Project PDF file (98vfr800partslist.pdf) which I think I downloaded from this forum yonks (long time) ago.

 

The diagrams in the service manual provide a better representation I discovered later.

 

spacer.png

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9 hours ago, wawasonqo said:

 

Do you happen to have their email address?

Contact is in the link

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If you have a little tyre air pump, you can use it to pop the pistons out. As previously stated remove the pads & then place them both loose in the caliper. Then use brake M/C to pump pistons most of the way out. Then remove the pads & hose & drain the fluid. If you don't have a piston puller,  clean & wrap the exposed piston ends with tape. Use small mole grips on the taped areas to wiggle them out

the last bit. If you are replacing the pistons then you can forgo the tape.
If they can't be wiggled out from there then move to next phase. 
 

Most pumps have a plastic tapered filler with a s schrader valve end, for what I don't know, but if you shorten it, it can be threaded into the banjo hole.  Connect your pump & use something to keep the loosest piston from popping out. The pressure will then be applied to the tight one.  Job jobbed. 

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3 hours ago, Mohawk said:

If you have a little tyre air pump, you can use it to pop the pistons out. As previously stated remove the pads & then place them booth loose in the caliper. Then use brake M/C to pump pistons most of the way out. Then remove the pads & hose & drain the fluid. If you don't have piston puller,  clean & wrap the exposed piston ends with tapeI. Use small mole grips on the taped areas to wiggle them

the last bit out. If you are replacing the pistons then you can forgo the tape.
If they can't be wiggled out from there then move to next phase. 
 

Most pumps have a plastic tapered filler for what I don't know, but if you shorten it, it can be threaded into the banjo hole.  Connect your pump & use something to keep the loosest piston from popping out. The pressure will then be applied to the tight one.  Job jobbed. 

Thanks.

 

I have a bicycle pump.

 

What is tapel?

 

As per the following post, how do I debug what is happening at the Master Cylinder end?

 

https://www.vfrdiscussion.com/index.php?/forums/topic/108993-rear-brake-bleed-delinkedde-linked-caliper-mounting/&do=findComment&comment=1149516

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What's wrong with using brake-fluid pressure to push piston out rest of way? As soon as piston clears end of bore, all pressure is released and it stops moving. Because fluid isn't compressed and there's little difference in volume between compressed and uncompressed fluid.

 

Air-pressure on other hand, can build up quite high pressure depending upon how stuck piston is.  It will continue to expand and push on piston even after it's out from caliper because compressed volume is so much smaller. Quite explosive and dangerous!

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How much do you enjoy being covered by brake fluid? Ask the other things nearby the same. 

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7 minutes ago, bmart said:

How much do you enjoy being covered by brake fluid? Ask the other things nearby the same. 

 

As per the following post, how do I debug what is happening at the Master Cylinder end?

 

https://www.vfrdiscussion.com/index.php?/forums/topic/108993-rear-brake-bleed-delinkedde-linked-caliper-mounting/&do=findComment&comment=1149516

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7 hours ago, bmart said:

How much do you enjoy being covered by brake fluid? Ask the other things nearby the same. 

Brake fluid doesn't come gushing out with explosive force! Watch the piston as you squeeze. As soon as piston leaves, you stop squeezing and get a tiny dribble, 1-2cc and that's it!

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6 hours ago, DannoXYZ said:

Brake fluid doesn't come gushing out with explosive force! Watch the piston as you squeeze. As soon as piston leaves, you stop squeezing and get a tiny dribble, 1-2cc and that's it!

 

correct!

 

Pay attention that both pistons come out equally.

One may have to "block" one (with 2 pads packed together) to allow the other one to "catch up"

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8 hours ago, DannoXYZ said:

Brake fluid doesn't come gushing out with explosive force! Watch the piston as you squeeze. As soon as piston leaves, you stop squeezing and get a tiny dribble, 1-2cc and that's it!

 

Not using your method (which is what I do now), but if someone is using compressed air, it sure does!  As I once sadly discovered, tiny droplets of brake fluid got everywhere in my garage--including on my other bikes' paintwork and windscreens.  Some of those spots are still there to this day...  :sad:

 

Ciao,

 

JZH

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  • 5 weeks later...
On 3/17/2023 at 3:09 AM, Skids said:

There are kits available - Honda VFR 800 Fi-1 01 Parts at Wemoto - The UK's No.1 On-Line Motorcycle Parts Retailer - I used these guys for my Fi-1 brake overhaul

 

I bought their Rear Brake Caliper Repair Kit which I may be receiving tomorrow but I'm still hoping to not use it if the problem I now have lies elsewhere.

 

Note: My brakes are de-linked.

 

I have installed a CBR600F4i Rear Master Cylinder and it appears I have all the air out of the lines but I'm not getting any grip of the disc by the pads. I can push the pedal all the way down but the pads aren't gripping the disc.

 

It appears that the caliper is now looser on the disc too.

 

I did lower the pedal height slightly. Should I reverse the change?

 

I left a weight hanging from the pedal overnight hoping for a similar result as when I used a strong rubber band to keep the front brake lever compressed overnight which helped to bring the pressure up.

 

Prior to all my recent maintenance, the bike has not been ridden for 15 to 16 years.

 

Although the bike has not always been inside, I have always used a Bike Cover on it (Nelson Rigg). However, with the Rear Caliper being positioned so low, is it more vulnerable to the weather?

 

If the pistons are stuck and I can't loosen them by application of the pedal, how can I extract them to replace the seals?

 

I need Home Mechanic ideas firstly.

 

Thanks!!

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  • wawasonqo changed the title to Rear Brake Caliper Overhaul - Alternative Piston Removal Methods?
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Squirt PB-blaster to loosen up any corrosion in piston.

 

Alternately push in & out. Use C-clamp to squeeze in. Then push out with pedal. Then repeat back & forth.

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