Topic: 1977 Hondamatic

[magnusV2]

Hi everyone, I need some help trying to un-seize the front brake caliper on my 1977 hondamatic. Is there anywhere I can buy a new caliper? Any comments are appreciated.

[BeSeeingYou]

No, but most of the time you can get it apart with the right technique.  What is the exact problem?  Is it seized to the rotor and or the piston stuck in the caliper?  To get the piston out dismount the caliper but leave it hooked up to the master cylinder and operate the lever to force the piston out.  Once you unbolt the caliper you should be able to break it free from the rotor if that's the problem. This has always worked for me even on two bikes that sat for 20 and 25 years.  Order a new piston seal and make sure you clean out the seal groove thoroughly.

[Hush]

What he said, I can't give any better advice than Srust58 has.

[raymond10078]

I had the same problem.  I did a lot of searching, and only one thing did it for me was . . . .

First, I bought a bolt at the hardware store - the same size/pitch as the brake line inlet.  Then, I used a hole punch on a old head gasket (copper head gasket from a 50cc Honda), and made a small circle of copper.

I put water in the caliper - until all air is removed.  Install both the bleed screw and the bolt with the (copper) gasket under it.  Tighten them up good.

Then, I put the caliper on a baking sheet, with a pan upside down, but over the caliper.  Put it all in the oven, and bake at 300 or so.

Eventually, the water boils, makes steam, and forces the piston out - usually with quite a BANG!  That's the purpose of the upside down pan (to catch the ejected caliper).  Overall, it took about an hour.

I had tried everything I could think of, and could find on the internet.  This sounded crazy - but it worked for me.

[Inigo Montoya]

I can add one thing. Put the caliper either in something like a box or in a towel to catch the brake fluid and the piston.

[magnusV2]

The problem is that the piston is stuck. Thanks everyone, I'm going to see what I can do with it. It just sucks because the bike is in running order... but no front brake lol. I rewired the bike, and everything works on it except the tail/brake light. Any Ideas?

[Spanner 1]

Ah, the old Boil-In-The-Bag caliper trick.... very good !  Also iffen you have a grease gun, it placed on the loosened bleed nipple ,a few pumps and the grease would force the piston out......

[Hush]

Probably because the front brake lever also activates the rear light, this maybe causing your brake light problem.
Tail/brake lights use two main wire colours  green/yellow=brake lights  brown=lights the earth should be solid green but on my chart it shows as black for some reason?

[tramp]

if your going to work on your bike
get a good manual

[DarkRider]

Ah, the old Boil-In-The-Bag caliper trick.... very good !  Also iffen you have a grease gun, it placed on the loosened bleed nipple ,a few pumps and the grease would force the piston out......

I have heard of the grease gun method a few times both on car forums and bike forums. Never heard of the boiling one though.