front left caliper for 84

[fjbiker84]

Today I noticed that my front left caliper has developed a very slight leak that appears to be coming from the caliper body. I had the caliper rebuilt with the help of a local mechanic several years ago.  After splitting apart the caliper I was made aware of two small rubber gaskets that seat in the oil passages between the two halves of the caliper body and are not available.  If this is where the leak is coming from what are my options?  It appears that the entire caliper assembly is no longer available.

[FJ1100mjk]

Here ya go...

https://www.rpmracingca.com/proddetail.asp?prod=M%2FC%3ACaliperORing 

[fjbiker84]

Thanks!!!   

[ribbert]

Go to a a bearing supplier or a brake shop with a caliper half and they will fix you up. I get all my seals and o rings from an industrial bearing supplier.
Don't fret, this is not a big deal.
Noel

[fjbiker84]

Yes, thanks. I panicked when I first discovered the problem but all is resolved now.  I've ordered three sets of these little gaskets from RPM.  Nice to have replacements for the other calipers even if they aren't leaking at the moment.

[balky1]

Just a bit of thread hijack: is it needed to split the calipers in order to change the seals around pistons (and pistons)?

[fjbiker84]

This is a photo of the caliper split apart when I was attempting to rebuilt it several years ago. This is as far as I could get because I couldn't pull out the pistons without risking damage to the pistons.  According to the mechanic who did the work, my caliper pistons were so gummed up that he had to put the calipers back together, hook it up to one of his bikes, and use hydraulic pressure to push the pistons out far enough to then split the caliper apart and pull the pistons out.  The two small gaskets are the things I think are leaking now.  Yamaha apparently never sold these separately.  Fortunately RPM does!

[balky1]

This is a photo of the caliper split apart when I was attempting to rebuilt it several years ago. This is as far as I could get because I couldn't pull out the pistons without risking damage to the pistons.  According to the mechanic who did the work, my caliper pistons were so gummed up that he had to put the calipers back together, hook it up to one of his bikes, and use hydraulic pressure to push the pistons out far enough to then split the caliper apart and pull the pistons out.  The two small gaskets are the things I think are leaking now.  Yamaha apparently never sold these separately.  Fortunately RPM does!

As far as I know you ARE supposed to push the pistons out with the calipers mounted. Otherwise, it is (almost) impossible.
But no one replied to my question posted earlier....

[FJ1100mjk]

As far as I know you ARE supposed to push the pistons out with the calipers mounted. Otherwise, it is (almost) impossible.
But no one replied to my question posted earlier....

I used an air compressor with a blow gun tip, to pop out the pistons. You have to be careful. Don't put your fingers where they shouldn't be. Also heard that a grease gun will fit the bleeder screw. Plug the fluid port, and pump the caliper with grease, and the grease will pop out the pistons. Sounds messy, but possibly effective. Never tried it though.

[balky1]

As far as I know you ARE supposed to push the pistons out with the calipers mounted. Otherwise, it is (almost) impossible.
But no one replied to my question posted earlier....

I used an air compressor with a blow gun tip, to pop out the pistons. You have to be careful. Don't put your fingers where they shouldn't be. Also heard that a grease gun will fit the bleeder screw. Plug the fluid port, and pump the caliper with grease, and the grease will pop out the pistons. Sounds messy, but possibly effective. Never tried it though.

Yes, I forgot the compressor. But if you don't have one.... Since you are mentioning puting fingers in wrong place, I suppose you didn't need to split the calipers to pop them out? Trying and trying to get this answer.... 

[FJ1100mjk]

Do a Google search with this: using air pressure to remove motorcycle caliper pistons youtube

You will have a couple of videos to look at, that provide direction.

[racerrad8]

I just pulled a new set caliper pistons and set them up to a set of calipers. Yes, you may be able to get the pistons out, if you have something thin enough to clamp the other side of the caliper and hold the other piston in, as the caliper is not wide enough to have both come out at once. Also, considering all the goop and grudge that usually builds up behind the o-rings in the caliper housing and how much of a pain it would be to get all of that cleaned out of there without splitting the caliper. It seems like you would be wasting much more time trying to screw around with not dis-assembling the caliper in the first place.

So to answer your question, yes, you could get away with not splitting the caliper.

Robert - RPM

[FJ_Hooligan]

Here's how I remove the pistons without splitting the caliper. 

Tie wrap one piston in place and use air or brake pressure to drive the other piston out. 

Remove the seals, re-install the piston and tie wrap it in place.

Remove tie wrap on other piston and use air or brake pressure to drive it out.

Like Marty said, watch where your fingers are.

[racerrad8]

Hooli,

Great idea with the tie wrap I didn't think of that. How do you ensure the orifice that travels through the housing and the goop that builds up around the square cut o-ring is all cleaned out? Not all are extremely dirty but we have done more than our share of ones that come in here and have a good amount of sludge, either partially blocking the orifice or completely plugged up in between the caliper housings. We also work on a fair amount of bikes that have been sitting for awhile and have a good amount of moisture contamination.

Robert - RPM

[Pat Conlon]

To get the majority out I use a small tooth brush and brake cleaner to scrub around the pistons before popping them out.

Hooligan gave me his tip 10 years ago and it works like a charm. For a Texan, he's an astute fellow........