Topic: 1975 CB550F0 Front shock seal replacement issues

[kitesurfer805]

I just got a 1975 CB550F super sport with 21K miles on it in fairly good condition and am starting to do some maintenance on it.  Everything to my knowledge is stock.  I could tell the front forks were leaking oil so i thought I would go ahead and change the seals out.  I watched some you tube videos of how to do and seemed simple enough.  I am a fairly good mechanic but motorcycles are new to me.  When I was trying to take the bottom Allen head screw off it just spins.  I loosened it 1 turn like the video said before taking the forks off.  The Allen screw is bolted into a part that can spin so there is no way to get it apart. I cleaned the shocks and added new oil and put them back together again.

So my first question is what do I do about this?  Are the forks no good now? 

During the install I noticed the brake would start rubbing on the rotor like the brakes were being applied when I would tighten down the caliper.   I played around with all the attach points of the caliper (support brackets etc).  Just prior to tightening the hardware the wheel it would spin freely  but as I tighten the bolts on the caliper and or the attach bracket it was like the brakes started being applied.  I worked on it for hours trying this and that and could not get it so the wheel would turn freely once the brake had been applied and released.  I took it on some test drives and at slow speeds and you can hear the disk rubbing or contacting something.   If you apply the front brake when you hear it while driving the noise goes away.

Is that a normal thing for the bike.  I was hoping it would  burn in and then loosen up but I doesn't seem to

My 3rd problem is the brakes won't pump up.  I have a vacuum bleeder so I used it but cannot get the brakes to pump up tight.  The diaphragm inside the reservoir is torn so could that be it?  I have ordered a new diaphragm. 

Don't understand why the brakes won't pump up since I did not do anything to them

What a PIA.  The job seemed simple enough and then everything started going wrong. 

[strynboen]

you need to split the caliber..klean all up inside...and put a new rubber seal inn..(.its the rubber seal vho retrack the piston.).so a old and dryed seal......you have not the full return move of the piston...so it hangs and is nosie..

often the piston is rusted  and pittet too..all make the free back moving..not happend and it all gives drag.
.if there is a bit dirt in the marster..the air gets trapped..so a good idea to klean the resuair..and pump some nev fluid through..and thek both holes is free..specily the mikro small bleed hole..

often i let my bike stands the night over..so airbubbels can break free and get up...dont Lock the handel..its then Blocks for the air to escape..back up the system..(its a big mistake many still belive on,, that hold the handel pressured vill open for the airstream up through the marster..its the oppersite vay..its bloks the air escape..but the pressure vill brake free some bubbels ,,as they get kompressed to smaller bubbels..but first get aut vhen the handel is losend up..any vay ...the end resultat is the same..bubbels gets aut of the system..and it hardent op the feeling of the handel..

[Redline it]

on the bolt that holds the slider onto the fork tube by screwing into the damper rod, usually comes out pretty easy with an  if you leave the spring in, drain the oil by the drain screw unless it's all beat up (the screw) or the big bolt that spins will drain it when it comes out. why it spins is because nothing holds the damper rod from spinning, unless you compress the fork,  the spring pressure holds the rod from spinning. if it's still in the triple clamp you can compress it with a motorcycle tye down if you're alone, or have someone sitting on the bike compressing the forks, it doesn't take much, and you don't have to compress the forks to assemble. first try a 3/8" butterfly air ratchet, set on high turning left, they usually work, just be certain the allen bolt isn't filled with dirt so that the allen socket fits in all the way and snug, no slop. if it doesn't work, compress the fork more, that part rarely has rust in it. 

[dave500]

heres Daves trick #679,drain your forks with no mess,you know those little plastic fittings for like fish tank air pumps etc?if you undo and remove the drain screw on your forks and don't bump or pump down on them the oil wont leak out but a touch,quickly force thread in one of those little plastic jiggers and hook up your no spill brake bleeding peanut butter jar gismos,you can then pump all the old oil out no mess!

[strynboen]

i drilled a 6mm bolt..and cut the head ..then a fuel line fits fine over..and like dave did..so it not sprayes all over..often need to thange the oil 2-3 times to get all dirt vashed aut..all that bad smelling komes from vater leaking dovn through the seal...and made the oil go rotten

[kitesurfer805]

On the brake rubbing issue:  Last week I took the brakes apart and cleaned it all up and put it back together again.  The piston was in pretty good shape and I cleaned it all up, just a little rust spot in the middle.  I did re-use the same o-ring though when I put it back together again.  I also flushed out all the old brake oil and put in new stuff.  I did it because the brake was dragging (same problem) and I lubed up the back side of the brake pad with caliper grease hope that was what was hanging up, it seemed to be a little better but got worse again after the fork change out. 

Good to know the seal should be the problem, I will order a new one and replace that.  Easy enough to to do:

Brake bleeding issue: looks like I will get back to that when I change out the seal so more to come on that.  I will have a new seal and a new diaphragm by then so hopefully it will work out.  When I was bleeding the brakes I use a vacuum oil recovery tank and it has a hose with a rubber end that fits over the bleed screw.  I hook that up and then pump up the handle and open the bleed screw.  I tried it both ways where I left the handle down and tried to suck fluid through the system and I also tried where I would pump it up and only open the bleed screw momentarily.  It worked ok for me last week but was not working well for me yesterday. I did it with the cap off the master cylinder so I can see when I need to add fluid and when I would pump up the handle every so often I would get a squirt back up one of the those holes and fluid when squirt out.  I got pretty good about making sure the handle bars were turned the right way so it didn't get any on the tank and I started squeezing softer which also help the squirt back.  Is the micro hole the one that does the squirt back because if it is then it's open for sure. 

[kitesurfer805]

The Allen screw turning and spinning issue:  I was able to figure out that by putting the spring in and compressing it helped locked things up but when I tried that I still got the same results.  I was working by myself so maybe I was not getting enough pressure put on them.  I will have to try that when I try again.  I do want to add some more into to that issue.  When I decided to stop and back up I had to put the screws back into the part again so I put the spring in and compressed it the best I could.  The screw on one shock seemed to thread into something and tighten up nominally but the screw on the other one seemed to get cross threaded and I could only get about 1/2 to 3/4 turn on it.  I am nervous about trying to change those seals.  I think my plan is going to be to see how bad the seal leaks and make a determination after that.

I was reading all the hondaman suggestions and in one of them he said to drill a hole in the top cap install a shreader valve and fill the shock with air (make an air shock out of it).  Does anybody have more into on that?  Has anybody done that and does it make a better shock?

[BomberMann650]

I’ve come to really appreciate a cordless impact drill. 
Chuck an allen socket to the end.  Set the assembled fork upside down on a floor pad.  Use the drill to turn the bolt out with one hand while leaning your weight into the fork with the other.  Just be careful you don’t slip and fall in the process.

When you’re ready to remove the seals, an electric heat blower comes in handy.