Front brake caliper re-build

[TownsendsFJR1300]

This am I finally got around to re-building the front brake calipers to my 07 as it had the original seals. On a good day, the front wheel, with a good decent spin might go 2 rotations. When wet, maybe 1 rotation.. Being their approx 5 years old, I figured their due and didn't want them dragging on a road trip burning up pads/disc's...

BTW, Yamaha calls for replacing the seals EVERY TWO YEARS.

I did clean them out about a year ago (original seals looked good) however they starting dragging some, especially after riding in the rain...

Several pistons were very happy in the bore and didn't want to come out but eventually did with the help of an air compressor, some paint mixing sticks (used as spacers to keep the pistons from flying out). BTW, you really couldn't tell the difference by feel or looking at the new seals vs the old seals

No corrosion/pitting, etc, assembly went smoother than dissassembly. Once bleed out and test ridden, I checked the "free spin".

With the new seals, I was now getting 4.5-5 full spins (same force)..

I suspect my pad life will be extended some as well as my MPG may improve slightly...

Buying all the seals, on-line for an 07 (4 piston pots each) was about $80.00 shipped to my door...

Something to check when doing basic maintainance and consider doing if there's excessive front wheel drag....

 

[NorcoT]

I was thinking about doing mine but havent got round to it. Last I checked my wheel spins about 2 revolutions with a reasonable amount of force, I took the calipers off, pads out, pumped the piston out a little. The piston that was inside of the seal was clean and shiny, the part outside was coated in a thick layer of dirt.. I took some brake cleaner and cleaned up the exposed part and reset the pistons.

After reassembling and a quick bleed they now rotate about 3 revolutions..

I now question whether I need new seals or not.. You can still hear them drag a little when you spin the wheel, but its not causing excessive wear / heat as far as I can tell.

 

[fazil]

Buying all the seals, on-line for an 07 (4 piston pots each) was about $80.00 shipped to my door

For 8 seals, it's a lot of money.
Every 2 years
We should find cheaper aftermarket seals.

 

[DefyInertia]

I was thinking about doing mine but havent got round to it. Last I checked my wheel spins about 2 revolutions with a reasonable amount of force, I took the calipers off, pads out, pumped the piston out a little. The piston that was inside of the seal was clean and shiny, the part outside was coated in a thick layer of dirt.. I took some brake cleaner and cleaned up the exposed part and reset the pistons.

After reassembling and a quick bleed they now rotate about 3 revolutions..

I now question whether I need new seals or not.. You can still hear them drag a little when you spin the wheel, but its not causing excessive wear / heat as far as I can tell.

3 rotations is pretty good. I wouldn't replace to seals in order to try to get more than 3 rotations. You may consider simply rebuilding them without replacing the seals though. It is pretty easy to do and you can polish the pistons while they are out, flush the calipers, inspect the seals, inspect/replace the springs, etc.

 

[Nelly]

Any pictures Scott?

Neil

 

[TownsendsFJR1300]

I was thinking about doing mine but havent got round to it. Last I checked my wheel spins about 2 revolutions with a reasonable amount of force, I took the calipers off, pads out, pumped the piston out a little. The piston that was inside of the seal was clean and shiny, the part outside was coated in a thick layer of dirt.. I took some brake cleaner and cleaned up the exposed part and reset the pistons.

After reassembling and a quick bleed they now rotate about 3 revolutions..

I now question whether I need new seals or not.. You can still hear them drag a little when you spin the wheel, but its not causing excessive wear / heat as far as I can tell.

If your getting 2 revolutions, IMHO, I wouldn't pull them apart but do just as you did. IMO, less than 3/4, start thinking about it...

My old, 04 FJR, when we got back from a road trip, the front brakes were noticably dragging (maybe 1/4 turn), rotors very warm, etc. The calpers on the 04 FJR are exactly the same as my 07 FZ6, so I was familiar with changing them.. There are two different sized pistons in each pot (07 and up, 4 piston pots each side), (06 and earlier, TWO pistons).

To do it every two years, IMHO is not needed unless their dragging or leaking. I suspect its to cover Yamaha's liability..

The $80.00 was an on-line cost, at the dealer for my FJR was $120.00 US, so I was very happy at $80.00. There's going to be some drag, the pads have to be close to the disc's or you'll have a bunch of free play in the lever before the pads touch.

As for finding cheaper seals, NO thank you.. That's approx 80% of your potential braking power, I'm NOT cutting any corners there... (I don't want some cheap, Chinese, crappy fitting seals anywhere near my bike)...

IMHO, if your going to pull them apart (pistons fully out), I'd replace the seals while there. It takes longer to bleed the dry system (even with two straight SS lines direct to the MC) than to do the job(thats with a Mity Vac too).

As noted above, I previously checked cleaned them and they were good for almost a year and started acting up again. It was time...

Even after cleaning them/flushing within a year, several pistons were a B..ch to get out. Without an air compressor, I seriously doubt you'll get all the pistons out un-less you grab them with a plyers (a big NO NO, don't bugger up the pistons)..

Sorry Neil, no pic's.

Pretty basic disassembly/re-assembly. With the air compressor, a long, pointy nozzle with a short piece of angle cut rubber(slipped over the nozzle) works great to put on that stubborn piston fluid inner orifice and blow the psiton out. And put a rag where the piston exits as IT WILL cause your fingers to get pinched badly..

Hope this helps...:thumbup:

 

[mave2911]

Ok, stupid question time.

As I don't have an air compressor, could I not pull the calipers off the bike, but leave the lines attached, remove the brake pads and use hydraulic pressure to get the pistons out? (i.e. pump the lever until they're fully extended - and if one is moving more than another, put a bit of finger pressure on it until the other one moves)

Cheers,
Rick

 

[NorcoT]

I have seen this done before, you have to either as you say pump out the pistons evenly by holding them in with fingers (although theres potential to jam your fingers in the calipers! better yet iv seen it done with a gclamp and a piece of plastic sitting against the pistons, pump the level and slowly unwind the gclamp at the same time.

You have to make sure you get both pistons out as far as possible, when one pops out the other must be far enough out you can grab it with your fingers and pull it out.

Obviously it's easier to do only one side at a time..

All im saying is that it works but its definitely not the recommended way to do things

 

[Nelly]

Ok, stupid question time.

As I don't have an air compressor, could I not pull the calipers off the bike, but leave the lines attached, remove the brake pads and use hydraulic pressure to get the pistons out? (i.e. pump the lever until they're fully extended - and if one is moving more than another, put a bit of finger pressure on it until the other one moves)

Cheers,
Rick

I don't have compressed air either, I wonder if a stirrup pump would be enough to move the pistons?
Neil

 

[TownsendsFJR1300]

As I mentioned in my first post, I used paint mixing sticks, cut down to allow the pistons to come to a certain, almost fully extended, position. You may try just removing the pads and using the disc's themselves to stop the pistons, they'll be out 3/4 the way..

If you don't have an air compressor, you'll have to do this with both sides at about the same time and add fluid (as the master cylinder will run dry).

Be forwarned, if an 07 or newer caliper, the opposite piston has to be just slightly in the bore for the opposite piston to have enough clearance to come out..

So make sure if you have a real sticky one (and you will have at least one stickier than the rest), you pump him out first, then get the opposite one.

Perhaps a little bit of grease on the pistons, then push back in and pump out again may work. You'll be cleaning the calipers compleatly anyway with brake cleaner and will later get rid of that grease anyway. A toothbrush works well with brake cleaner when cleaning the grooves which the seal/dust seal resides..

I have a 25 gallon, 150 PSI compressor so I didn't bother playing the balancing game but I believe using the disc's themselves (calipers mounted)with NO pads and adding fluid will get the majority of the pistons out..

BTW, once ONE PISTON breaks the seal, pumping the rest out hydraulically is NOT POSSIBLE... There's an orifice between each piston hole that allows fluid to flow inbetween the chambers.

Worse case scenerio and one's really stuck, bring it somewhere with an air compressor, won't take a minute or two to blow out...

 

[TownsendsFJR1300]

Ok, stupid question time.

As I don't have an air compressor, could I not pull the calipers off the bike, but leave the lines attached, remove the brake pads and use hydraulic pressure to get the pistons out? (i.e. pump the lever until they're fully extended - and if one is moving more than another, put a bit of finger pressure on it until the other one moves)

Cheers,
Rick

Yepper, read the above post.