Topic: Front wheel wont move!

[trueblue]

The pads should drag just enough to just touch but not enough to slow the wheel if spun.  You may be able to hear them rubbing the disc, which isn't a concern. 

Don't put standard grease near the caliper piston, it will cause the seals to swell and compound your problem.  The piston gets all the lube it needs from the brake fluid inside the caliper. 

When reassembling the caliper after cleaning it out, use a little rubber grease on the rubbers to assist in putting it together.  It is castor oil based and doesn't affect the seals.  If you can't lay your hands on rubber grease you can use a little brake fluid to lube the seals.  If you do this though be careful around your paint .

[PeWe]

I had problem with braking front wheel when I steered 25-45 degrees or so. I had not tightened the nuts holding the wheel so it could move.

I knew that all bolts were not tightened. This was something I had planned to check before riding the bike. I hope I'll remember all

[DaveBarbier]

The pads should drag just enough to just touch but not enough to slow the wheel if spun.  You may be able to hear them rubbing the disc, which isn't a concern. 

Don't put standard grease near the caliper piston, it will cause the seals to swell and compound your problem.  The piston gets all the lube it needs from the brake fluid inside the caliper. 

When reassembling the caliper after cleaning it out, use a little rubber grease on the rubbers to assist in putting it together.  It is castor oil based and doesn't affect the seals.  If you can't lay your hands on rubber grease you can use a little brake fluid to lube the seals.  If you do this though be careful around your paint .

Ok, just checking that mine are still dragging way too much, haha. And maybe I should clarify; I used caliper slide grease for the pad and brake assembly lube for the piston.

Since then, I got my new seal and took apart my front caliper. My piston is garbage. Rusty and pitted. I emailed a member here for one of those phenolic pistons. I'm excited about that. My caliper seems to be alright. No scratches and very smooth to the touch but a lot of white gunk in the seal groove. Going to clean that out today with a brass wheel brush.

There's so much knowledge in this forum it blows my mind. So many questions have been answered.


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1978 Honda CB550K

[trueblue]

Ok, make sure you clean the groove in the caliper out good.  It should be a nice square shape.  Keep us posted on how you get on

[DaveBarbier]

I cleaned out the seal groove and it's super clean. They should change the saying to "This whistle is as clean as Dave's caliper seal groove." I'd say it has a better ring to it anyway.

I couldn't get a brass wheel. Instead I soaked a price of a shop towel in PB Blaster and let it sit in the ring for a couple hours. Then I, carefully...and with a small dental mirror, used a carbon steel brush on my Dremel. Piston will come in a couple weeks and I can re-assemble.


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1978 Honda CB550K

[Don R]

YOU GO! I mean er, stop.

[DaveBarbier]

Ok, just to have things documented...I got the new piston today. Phenolic for $44 from Godfrey, a user on this forum. It's so light and a honeymoon fit.

Installed new seal and piston with assembly lube and pad with high vacuum grease. Going to bleed with DOT4 tomorrow as the new Nissin MC I have calls for it. I'll have to flush out the DOT3 that's currently in the lines. After that, brakes will be all finished with new parts and my pad should (will?) retract as it should.

Any problem with doing the caliper rebuild without filling it with brake fluid? I think it should be fine but curious if I'll run into any bleeding problems.


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1978 Honda CB550K

[trueblue]

It'll fill up when you bleed it

[DaveBarbier]

Ok so got the brakes back together. Bled the system and it seems to be a lot better. I noticed that the phenolic piston is a little longer than the stock one and when I release the brake lever  the wheel still drags a little. Much less than before, though. I tried to adjust the arm but nothing made it completely free. Could the new piston be too long? Not giving the clearance needed to accommodate new, thick pads?

Any way to remedy this? Maybe sand down the pads a hair? Add a shim between the caliper sides?


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1978 Honda CB550K

[Don R]

The solid side of the piston is in and the pad fits in the hollow side right? Don't ask how I know that.

[DaveBarbier]

The solid side of the piston is in and the pad fits in the hollow side right? Don't ask how I know that.

Yup, hollow side out facing the pad.


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1978 Honda CB550K

[DaveBarbier]

Don't shim the caliper. If your wheel is still dragging after a full bleed, good lever pressure, etc. then you may have to lightly sand the pad face. BUT, before you do that, ride the bike about gently. It may be your rotor face is out of true.

I've found that until the system is fully bled, the caliper doesn't seem to want to pull the piston back, but after some use while riding, the pads seat in much better. But I repeat, ride gently and carefully!

If you're still encountering drag, check that the rotor is not binding in specific spots (bike on center, spin wheel by hand). If everything checks out, then use a sanding block with paper, and cross the pad at 45 degrees to avoid warping the pad. Gently, Grasshopper, very gently. 400 grit should be plenty to ease the pad face.

I've always used brake fluid to soak my seals in before assembly. It's all you need as the seal with impregnate with the fluid then live it's life immersed in it. Lube the backs of the pads with appropriate lube. Piston needs nothing but a smear of brake fluid to install through caliper seal.

As you put it earlier, your caliper inside can never be too clean!

Last bit: I always use anti-sieze when assembling the caliper (on the bolts ONLY) to  avoid tearing out the 10MM threads on the backside of the caliper. Especially if you are going to assemble/disassemble regularly. Just be sure not to use too much and wipe away any residue from the caliper housing before remounting it.

So I was told by Godfrey that the piston is suppose to be taller because it's supposed to render the nylon washer obsolete. So it's just the pad touching the phenolic piston. That should give me a few more millimeters in clearance and should be all I need. I wasn't aware that I don't need the nylon washer with this piston.

But if that doesn't work then I'll try the stuff you mentioned. Thanks Calj737, and good idea with the anti seize for the bolts. I'll totally do that.


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1978 Honda CB550K

[DaveBarbier]

Ok, just before my Thanksgiving dinner I removed the nylon washer and it's perfect. Wheel spins super free and the brakes are hard as a rock.

Thanks guys, happy Thanksgiving.


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1978 Honda CB550K