Front Brake Issues

[Lastwachter]

I have a 1978 GL1000. I had removed the front calipers and brake pads. I replaced all 3 of the front original brake lines with new ones, reattached calipers, lines and pads. Filled the master cylinder with DOT 3 brake fluid and began to pump with the right caliper line open using the Motion Pro mini bleeder, Randakk suggested. I continued to do this until I was getting fluid through the clear tube without any bubbles. I tightened it up before any air was sucked back into the tube. I then did the same on the left side. As soon as I loosened the left bleeder, fluid pushed through into the clear tube. I pumped a few times to get the fluid moving through with no air bubbles and tightened that one back up. I then filled the master cylinder so that the rubber filler piece just barely floated while sitting in the cylinder on top of the fluid and then added the lid. I now have two issues.

-The cylinder makes a squishing noise. I checked the rubber filler and it has no holes, it suctions to my palm and stays there. I then cleaned all the pieces including the nylon washer of any fluid but there still seems to be air moving around under the lid making a squishing noise. Is this normal? Is there something I can do about it?

-The brakes work... however, they are not completely releasing. The front tire is hard to spin when the brakes are released. When compressed they stop the bike entirely, however when released I can barely push the bike at all. Suggestions?


Thanks for everyones help! The bike is almost ready to ride. I will be sure to post everything I have learned along the way to hopefully help others.

Lastwachter

[SnoBrdr]

As far as the brakes binding, did you measure the pads when you put them back in?

There is a specific amount of clearance needed or they will not be aligned properly and can bind like you are describing.

[Lastwachter]

To be honest I did not. They seemed to have a lot of pad left on them. I will do so today, thanks!

[Fred Camper]

Two issues, the left caliper need to have static clearance before you tighten the axle stay. The other is there is a very tiny bleed hole in the master cylinder that aids in brake release. You need a very tiny wire to probe that port to be sure it is clear. There is a nice pictorial I can link if you need it or I bet you find it with google using NGWClub and "brake release" in your search.

[Lastwachter]

Two issues, the left caliper need to have static clearance before you tighten the axle stay. The other is there is a very tiny bleed hole in the master cylinder that aids in brake release. You need a very tiny wire to probe that port to be sure it is clear. There is a nice pictorial I can link if you need it or I bet you find it with google using NGWClub and "brake release" in your search.

Hi Fred.

Can you elaborate on static clearance?

Also, I am noticing in my manual a shim that goes up against the pads. I do not have these for either set of front pads. Do they come with the pads themselves? As in, if I go buy new sets at say Advanced Auto Parts, will they come with them?

Thanks!

[SnoBrdr]

Two issues, the left caliper need to have static clearance before you tighten the axle stay. The other is there is a very tiny bleed hole in the master cylinder that aids in brake release. You need a very tiny wire to probe that port to be sure it is clear. There is a nice pictorial I can link if you need it or I bet you find it with google using NGWClub and "brake release" in your search.

Hi Fred.

Can you elaborate on static clearance?

Also, I am noticing in my manual a shim that goes up against the pads. I do not have these for either set of front pads. Do they come with the pads themselves? As in, if I go buy new sets at say Advanced Auto Parts, will they come with them?

Thanks!

No the shims are NOT included with the pads and they are no longer available from Honda.

Do you need them? Who knows.

I find that one of the biggest problems when doing front brakes is that people don't compress the piston fully in the caliper.

We think we have but usually we have not.

After 36 years things probably need to be cleaned and/or rebuilt.

Especially the calipers as things tend not to slide well after so many years.

[Lastwachter]

I find that one of the biggest problems when doing front brakes is that people don't compress the piston fully in the caliper.

We think we have but usually we have not.

Using a C-clamp I compressed them flush, however if you have compressed them enough so that the they sit on the rotor with the pads and the wheel spins freely before you start to pump the brakes, can not having them fully compressed affect its performance?

[SnoBrdr]

I find that one of the biggest problems when doing front brakes is that people don't compress the piston fully in the caliper.

We think we have but usually we have not.

Using a C-clamp I compressed them flush, however if you have compressed them enough so that the they sit on the rotor with the pads and the wheel spins freely before you start to pump the brakes, can not having them fully compressed affect its performance?

I like to fully compress them so that I know that the piston can travel it's full length.

I also use the C clamp method.

[Lastwachter]

Today my next step will be to replace the brake pads and compress them both again fully. I'll then give them another try. If that doesn't work, I will pull the caliper apart and give it a good cleaning.

[SnoBrdr]

Today my next step will be to replace the brake pads and compress them both again fully. I'll then give them another try. If that doesn't work, I will pull the caliper apart and give it a good cleaning.

If you are going to pull the caliper apart, you might as well rebuild it.

Clean off the pistons, hopefully they are not pitted to badly or rusted.

Kits are readily available to rebuild them, as well as the pistons.

It's the rears on the 78s where the pistons are hard to come by.

I had to get them from the only place in the world that makes them.

I also needed the seal that goes between the halves of the rear caliper, found the last tow in the world over in England. Cost about 41.50 each but $10 to ship them.

They are now made in this country but they cost $15 EACH.

But I digress.

[Fred Camper]

The forks are not spread perfectly for the caliper to rotor clearance. So a feeler gauge is uses to set the fork spacing as the front left axle nuts are tightened.

But I bet your real issue is a plugged return in the master and not your calipers as you say it spins until you apply the brakes. It is that tiny port in the front master that allows pressure release then the rotor runout pushed the pistons back.

You will have to scroll down to find this little hole but this thread will help you find it.
http://ngwclub.com/forum/viewtopic.php?f=9&t=9156

[WingAdmin]

You can see an explanation of the return port (for the GL1100, but it's very similar) starting at step 8 here: How to rebuild your front master cylinder