Front Brake Not Right, But Why

[VegasNewbie]

I noticed my front wheel ('82 Seca) was squeaking and found that it wouldn't spin freely. I bled the brakes about a month ago, but still had these symptoms. So today I looked at the brake pads and saw that there was no visible space between the pads and the rotor. I took the caliper off to have a look.

After spending several quality hours with the manual and watching videos on YouTube, although I learned a few things, I'm stumped and know one or more of you can give me a clue card.

There were a few problems I found. I found the caliper had a tough time moving in relationship to the mounting bracket. I think there was too much grease on the pins because things worked much easier after I cleaned that up and applied a little lithium grease to them. The pads are pretty new and the grease pretty clean, so I think they were worked on recently.

In this first video, you'll see the pad on the non-piston side is loose. I'm dubious that this is by design, but please let me know. The manual says there should be a spring and a shim, both of which are there.

In the 2nd video you'll see that there's a nice gap between the pads and rotor until I pump the brake until the pads hit the rotor and don't rebound back. Not sure why that's happening. The piston looks clean and does go all the way back in with a C clamp. I took it apart 3 times (although didn't get the piston all the way out) and don't see anything that would prevent it from moving.

In the 3rd video, you'll see that I'm back to my original condition of the pads rubbing on the rotor.

Oh, and to top it off, one of the screws on the master cylinder cover is now stripped... <sigh>

Sorry for the rough videos, I filmed with my phone with just 2 hands.

I'm looking forward to any suggestions you have. I'm off the road until this is solved.

 

[BBS360]

Still learning what's "normal" on these bikes but I believe it's normal for the pad and rotor to be in contact.
The piston makes a very tight seal in the caliper. They're tough enough to move by hand. The only real mechanism in the system to pull back on the piston is the diaphragm in the master cylinder.
What condition is the master cylinder in? Without a tight seal you'd lose the slight pull that the diaphragm exerts on the brake fluid.
I suspect one of the more experienced members will confirm that the contact and drag is pretty normal.

The video of the loose pad is probably also normal. Are the pads overly loose when the caliper is installed on the rotor?

I made the mistake of ordering the specific yamaha part # to replace my missing MC screws. The same type can be found for much less on ebay.
Silver Phillips:http://www.ebay.ca/itm/M4X12-Hex-Soctket-Flat-Head-Hex-CS-Screw-For-HSP-1-10-ON-ROAD-RC-CAR-4X12MM-/111515173201?pt=Radio_Control_Parts_Accessories&hash=item19f6d28151
Black hex-heads: http://www.ebay.ca/itm/M4X12-Hex-Soctket-Flat-Head-Hex-CS-Screw-For-HSP-1-10-ON-ROAD-RC-CAR-4X12MM-/111515173201?pt=Radio_Control_Parts_Accessories&hash=item19f6d28151

 

[VegasNewbie]

I think the master cylinder is in good shape - haven't seen anything to indicate otherwise other than really gross fluid that I replaced. I'll bled the system again once I get the screw out - thanks for the tip on where to get new ones.

I read on another thread that the brake lines can decompose from the inside and cause problems, so replacing the brake line looks to be a to-do.

I did hear air blow back into the MC when I clamped the piston back into the caliper. This happened after I received fairly strong resistance when getting the piston back in, and after I heard the air, it moved easier.

I had the caliper connected to the MC and used the brake system to move the piston out as far as I could. That's why air got into the line - I think.

 

[VegasNewbie]

I put it all back together, bled the brakes and adjusted the cable. All nice and tight now.

It looks like I'll need 2 stainless steel hoses for this bike. There's a short one from the MC to a gizmo just under the handle bars, and then another from the gizmo to the caliper. Wonder why they did that rather just run a single one?

I'll be onto the petcock replacement and new clutch lever next.

 

[melbs5150]

My front was completely stuck on mine, so today I pulled the caliper and removed the pads. The piston is stuck. I'm going to go pick up some simple green tomorrow (I don't use brake cleaner from a spray can on my bikes) and see if I can get the piston to move back.

I have a stripped screw too. Best thing you can get is the stripped screw remover set from craftsman. That, and the stripped nut/bolt set they sell is worth it's weight in gold, IMO.

 

[VegasNewbie]

Welcome to the forum!

I did get a couple of sizes of screw extractors yesterday and got the screw out. I'll put the set on my list.

Since I'm new, why don't you use spray on brake cleaner?

 

[melbs5150]

Spray brake cleaner can blow debris back into the line. That's why I don't use it. Not saying there is anything wrong with it, just don't want the risk. I've been using simple green for years on my calipers.

And steel braided lines are the way to go!

 

[flutterball]

As for the two part brake line in the front, my guess is so they could keep the front lines better attached to the forks, that being said I just put a single stainless steel braided line on my front wheel, just made sure it didn't move around to much. Cleans up the front and much easier with less banjo bolt's and washers. Stainless braided lines are the way to go on the seca, heck any bike. You can buy rebuild kits for the master cylinder, if your updating everything else, may as well that too, since its not that expensive, and if switching limes have to re-bleed anyways.

 

[VegasNewbie]

Thanks flutterball, I've been thinking about what to do with the brake line, so it's good to hear what you did.

Good advice on the master cylinder too.