Question about disk brake calipers

[jrswanson1]

Are all disk brake calipers a standard size?  Specifically, if I want to swap out a Honda two-piston caliper for a Brembo, do I need one to specifically fit this application or can I get any two-piston caliper and put it on?  Thanks.

[Speeddog]

Generally, not a standard size.

[Slide Panda]

What he said.

As you might expect many bikes coming from the same manufacturer will share parts between models and years. For example the rear caliper for my 2000 900 can be replaced with one sourced from a 2008 695 - and was. But, I'd not be looking to an SV650 as a donor...

Calipers will have all sorts of differences - inlet position, pad size, pad shape, distance between mounting holes, distance from mount to pads etc etc etc

What's up with your caliper? You bike is quite new. Getting ready for that last track day in october? You know you want toooooo....

[jrswanson1]

I picked up a 1983 Honda V45 Magna Saturday with 15,000 miles on it.  The front disk brakes were seized, so moving it was quite the chore.  If the calipers were bad, I was going to see if there was a simple swap for better brakes, but it looks like that's a no-go.  Oh well, I'll fix these, and clean all four carburetors.  I got the bike for $200, so no big loss.  I can part it out for more. 

[Slide Panda]

Do the calipers function? Sized how? Some times, on the bike that's sat a very long time the rotor will rust to the point its stuck to the pads. A bit of muscle can free that up. But if the calipers are not working due to some internal flaw... then they might be goners. But you can (usually) pop the pistons out of a caliper with compressed air. Just make sure you have something soft like an old towel between them so they dont' collide metal to metal. And it doesn't take much air pressure at all to do - like 10 psi *maybe*


And he dodges my track day question again!

[ducpainter]

Parts for those might be available.

It's only on more modern models that manufacturers decided we were to stupid to repair brake systems.

[jrswanson1]

Do the calipers function? Sized how? Some times, on the bike that's sat a very long time the rotor will rust to the point its stuck to the pads. A bit of muscle can free that up. But if the calipers are not working due to some internal flaw... then they might be goners. But you can (usually) pop the pistons out of a caliper with compressed air. Just make sure you have something soft like an old towel between them so they dont' collide metal to metal. And it doesn't take much air pressure at all to do - like 10 psi *maybe*


And he dodges my track day question again!

Assuming my wife gets this job, I will endeavor to go to track day.  

I took one of the calipers off the bike.  The pistons were pushing the pads onto the disks.  Taking it off took some finagling.  After getting the pads out, the pistons are still sticking out.  I'm picking up a couple of c-clamps to try to get them to close.  I shot some WD-40 around the pistons and hopefully that will loosen them up some.  Then it's on to the second caliper.  If I can get both of them working, the bike is going to the shed for carb cleaning.  Stupid ethanol gas.

[Slide Panda]

Assuming my wife gets this job, I will endeavor to go to track day.  

Track day costs the same as your project bike... Just sayin'

[carbmon]

Looks like caliper internal parts/seals/etc are still available through www.ronayers.com at reasonable prices for your Magna.

Parts for the front calipers for your '83 VF750C are HERE

Ayers has been a reliable source for parts for my older Kawasaki - sometimes there's a bit of a wait while they get things from manufacturer warehouses, though.  Note, too, that often local dealers will match Ayers price when you show 'em the cost. 

Have fun!

[jrswanson1]

Track day costs the same as your project bike... Just sayin'

 The bike is for the wife.  She won't get on the Monster, but she'll ride a cruiser.  I'm trying to get her to ride more, she doesn't get out much since she lost her job.  Plus this is a project we're both working on.  

[jrswanson1]

Looks like caliper internal parts/seals/etc are still available through www.ronayers.com at reasonable prices for your Magna.

Parts for the front calipers for your '83 VF750C are HERE

Ayers has been a reliable source for parts for my older Kawasaki - sometimes there's a bit of a wait while they get things from manufacturer warehouses, though.  Note, too, that often local dealers will match Ayers price when you show 'em the cost. 

Have fun!

Thanks for the links!  It looks like one of the rubber seal things is a little torn up, I'll be hitting the local Honda dealer for that part.  Everything else seems fine except for the pistons sticking out and the families of spiders I chased out of there! 

[jrswanson1]

I picked up two C-Clamps on the way home and tried moving the pistons in the calipers.  They are not frozen open, they both move freely.  However, when I push one in with one of the clamps, the other pushes out.  I tried pushing the other piston in, the other moved out.  I can't push both in at the same time.  I have not gotten the other brake caliper off since that involves some voodoo I don't know about yet.  So I'm guessing that something is blocking the brake line somewhere.  Would too much brake line fluid cause this?  I haven't looked in the right coffin and the glass is glazed over so I can't see into it. If it's the brake hoses, I might just snag the braided lines and swap the original rubber ones for the nice ones.

[ducpainter]

I picked up two C-Clamps on the way home and tried moving the pistons in the calipers.  They are not frozen open, they both move freely.  However, when I push one in with one of the clamps, the other pushes out.  I tried pushing the other piston in, the other moved out.  I can't push both in at the same time.  I have not gotten the other brake caliper off since that involves some voodoo I don't know about yet.  So I'm guessing that something is blocking the brake line somewhere.  Would too much brake line fluid cause this?  I haven't looked in the right coffin and the glass is glazed over so I can't see into it. If it's the brake hoses, I might just snag the braided lines and swap the original rubber ones for the nice ones.

That's pretty normal as the passages in the caliper are larger than the fluid return port in the master.

Try removing the cap. If that doesn't work you can crack the banjo bolt to allow fluid to escape.

[jrswanson1]

After asking here and the V-4 forums, I'm figuring the problem is somewhere in the brake lines.  My plan is to pop the top off of the coffin to take a look, since the glass is completely opaque.  If that's fine, I'll close it up, open up the lines at the calipers, and drain the fluid out.  I'm picking up a couple of bottles of brake fluid on the way home today, along with a new battery.  I'll flush out the old brake fluid, and put new stuff in.  Bleeding brake lines is fun, right?