Topic: CB 550 Master Cylinder Question

[edbikerii]

I just installed a new 14mm master cylinder from ebay seller usa-motorcycles-inc.com.  This appears to be the same master cylinder referred to by both Moto-Bunny and rlarkin70.  The pictures in the ebay listing were identical.  The master cylinder is exactly as advertised, and is quite nice.  I like the fact that it is shorter in length to the end of the banjo bolt, so it gives me more clearance next to my gauge with my shorter GP bars.  I like the built-in brake light switch, but I'm not using it yet.

That's the same seller I bought mine from - they list a lot of these master cylinders under all different cycle types.

I surprised you didn't find it better than the stock one. On my bike, the OEM unit WAS way visibly corroded and leaking fluid. I guess the comparison wasn't fair since the OEM one was old and worn out? I still found the braking improvement dramatic though and its now going on like a year and a half on near daily use and still working great! (prolly 3000+ miles, maybe)

I like the look of the replacement unit better too - the OEM one kinda looks like a little cold cream jar sitting there or something?. . .   

       

MotoBunny, don't get me wrong, I'm happy with the purchase for various reasons, including the cleaner look, the additional space on the bars, the brake light switch, the nice leak-preventive banjo washers, the nice positive seal on the reservoir, the mirror mounting hole, etc.

But, yeah, in the end, I think your improvement must have been due to your old master cylinder being so worn out or leaky.  Have you ridden new motorcycles with "good" brakes recently?  Since I bought my Yamaha Seca II, I learned that modern bikes (even those with only two piston calipers and singe disks) have brakes that are light years ahead of the CB550s.

I'm not sure if the big problem is the single piston caliper or what?  I don't know of any semi-bolt-on caliper upgrades, so I'm grabbing at straws trying to change the master cylinder.  Many modern bikes have single disks and they brake just fine -- way better than the CB550.  The big difference seems to be either in the multi-piston caliper or in the master/caliper ratio.  I've used Ferodo pads in the past, but the system still sucks.

[MoTo-BunnY]

MotoBunny, don't get me wrong, I'm happy with the purchase for various reasons, including the cleaner look, the additional space on the bars, the brake light switch, the nice leak-preventive banjo washers, the nice positive seal on the reservoir, the mirror mounting hole, etc.

But, yeah, in the end, I think your improvement must have been due to your old master cylinder being so worn out or leaky.  Have you ridden new motorcycles with "good" brakes recently?  Since I bought my Yamaha Seca II, I learned that modern bikes (even those with only two piston calipers and singe disks) have brakes that are light years ahead of the CB550s.

I have never ridden anything but old Honda SOHC-4s actually. .  .lol. Many, many moons ago on the back of a CB350 then a CB750 and now on the front of my own CB500 and a few times on my friends '79 DOHC so no, I totally don't have ANY newer bike experience - none newer than '79.  . . LOL       (and probably won't any time soon, mainly due to $$$!  lol)

One thing I was thinking though, did you go with the braided brake lines when you changed the master cylinder, too?  Seems like when I was all researching brake stuff here on the forums, several peeps commented on THAT being the change that created the stiffer, more responsive braking that you are seeking? (like, no sponginess or whatever - the old all rubber ones can "balloon' or something)  I have yet to do that upgrade, myself, but will soon when I (finally) do the dual front disc conversion to mine (still gathering all the pieces to do it). 

Hope you find your braking nirvana - keep us updated here! (I am all about really good brakes on my cycle because going fast is kewl and all but um, being able to stop is pretty important?      )

[edbikerii]

MotoBunny, don't get me wrong, I'm happy with the purchase for various reasons, including the cleaner look, the additional space on the bars, the brake light switch, the nice leak-preventive banjo washers, the nice positive seal on the reservoir, the mirror mounting hole, etc.

But, yeah, in the end, I think your improvement must have been due to your old master cylinder being so worn out or leaky.  Have you ridden new motorcycles with "good" brakes recently?  Since I bought my Yamaha Seca II, I learned that modern bikes (even those with only two piston calipers and singe disks) have brakes that are light years ahead of the CB550s.

I have never ridden anything but old Honda SOHC-4s actually. .  .lol. Many, many moons ago on the back of a CB350 then a CB750 and now on the front of my own CB500 and a few times on my friends '79 DOHC so no, I totally don't have ANY newer bike experience - none newer than '79.  . . LOL       (and probably won't any time soon, mainly due to $$$!  lol)

One thing I was thinking though, did you go with the braided brake lines when you changed the master cylinder, too?  Seems like when I was all researching brake stuff here on the forums, several peeps commented on THAT being the change that created the stiffer, more responsive braking that you are seeking? (like, no sponginess or whatever - the old all rubber ones can "balloon' or something)  I have yet to do that upgrade, myself, but will soon when I (finally) do the dual front disc conversion to mine (still gathering all the pieces to do it). 

Hope you find your braking nirvana - keep us updated here! (I am all about really good brakes on my cycle because going fast is kewl and all but um, being able to stop is pretty important?      )

Yes, I also have stainless braided lines, which were purchased from Paragon Performance from components so that I could mount things up more flexibly as needed when I upgrade things.

I went for a beautiful ride with a passenger today, and yes, I now really appreciate the firmer feel of the new master cylinder.  I'm sure now that it is much firmer than the old one, and it cannot possibly be solely because of the old fluid or air that was in the system.  The lever is almost rock hard now.  I still don't feel that the bike stops better, but, the lever does definitely feel better.

It almost feels like the caliper doesn't really grab the disk.  It's like the caliper keeps on sliding regardless of the pressure applied.  I guess that "wooden" really is the best way to describe it.  Imagine if your brake pads were made out of wood, and the disk were polished.

I'm going to try roughing up the disk with scotchbrite or sandpaper as well as roughing up the pad surfaces on the belt sander for a second or two, perhaps.

[MoTo-BunnY]

Did you use the Dow High Vacuum Grease for your brake caliper?  Anything else, even "super-duper ultra mega Hades-like temperature brake grease" found at the auto parts store will STILL heat up, liquefy, and run down onto your brake disc, thus lubricating the brake pad - much to your dismay.

The Dow grease was hard to find and hella-spendy (like around $30+ a tube, new?!?) but I finally found some on eBay for "only"$15. It was a whole different game - really weird grease that is super persistent and slippery. Its also super heat resistant and stays a gel at high temperatures. I have found a lot of other uses for it other than brake stuff, too.



That's what I found in my experience, anyways, and it has been mentioned on the board here, a few times. (where I learned it from *duh*    lol)

I roughed up my brake disc once with one of those pumice blocks (used for cleaning grills - also works great on rusty spokes). It stopped all squeaking and braking was great for like 100 miles and then the disc was all polished up again. . . . lol.

Wish ya luck in your adventures in brake-dom!   

[edbikerii]

Thanks, Moto-Bunny,

I hit the garage again tonight!

I used 80-grit sandpaper on the pad sander to hit the rotor.  When I was done, it looked nice and roughed up on the outside, but the spoke side was impossible to hit with the pad sander.  I manually sanded it perpendicular to the direction of rotation.  Seemed pretty good.

I pulled the caliper and pads, noting that the last set of OEM Honda pads I had installed looked brand new!!!  They had about 1000 miles on them, but no appreciable wear whatsoever.  They seemed to have lots of "sintered metal" embedded in them, so I put in an older set of pads that I had lying around which were still about 3/4.  I sanded their faces, and chamfered their edges.  I believe that they were original OEM Honda pads from 1977 that had been on my old parts bike.  They seemed to have less metal in them, so my thinking is that they will grip better, even if they don't wear as long.

I used a product called Syl Glyde, which is what I used last time, and I saw it inside the caliper right where I had put it.  It doesn't seem to have liquified.

So, then I took it for a ride.  At first the brakes seemed great!  But I did a couple of low-speed full stops to try to help the pads bed-in.  Within a few minutes I was pretty sure the performance was getting worse.  I rode for about two miles.  When I pulled into the garage, the spoke side of the rotor seemed to be mirror-smooth already!

I think I'm going to get more organic brake pads.  I know I used some Ferodo pads a while back, and got only about 3500 miles out of them before the inside pad was completely worn out.  That was back before I had ever known what a modern bike brakes like, so I was pretty happy.  I might try the EBC organic FA13 as I had some EBCs on my Yamaha Seca II, and they were great.

When the new organic pads come in, I'll try de-glazing the inside of the rotor again.  I'll sand and clean the entire rotor again.

[TwoTired]

I used a product called Syl Glyde, which is what I used last time, and I saw it inside the caliper right where I had put it.  It doesn't seem to have liquified.

That is absolutely the wrong stuff to use in this application.  That stuff contains silicone but is mostly petro base.  It will weep and creep with time and especially so with heat.  You just explained why your brakes don't have any power, being well lubed where you want the friction.

I did an oven test with that stuff compared to the Dow pure silicone grease.  Sylglide started weeping pretty much as soon as it hit the pan and got worse as the temp climbed.  By 300 degrees F it had mostly vaporized leaving a brown hard residue.  The Dow stuff never looked or behaved any different right up to the 550 degree limit of my oven.

I ruined a set of brand new pads because the parts counter man told me that was the correct stuff.  Stupid jerk.  One look at the MSDS afterwards confirmed my suspicions.  The oven test was the nail in the coffin.

Cheers,

[edbikerii]

I used a product called Syl Glyde, which is what I used last time, and I saw it inside the caliper right where I had put it.  It doesn't seem to have liquified.

That is absolutely the wrong stuff to use in this application.  That stuff contains silicone but is mostly petro base.  It will weep and creep with time and especially so with heat.  You just explained why your brakes don't have any power, being well lubed where you want the friction.

I did an oven test with that stuff compared to the Dow pure silicone grease.  Sylglide started weeping pretty much as soon as it hit the pan and got worse as the temp climbed.  By 300 degrees F it had mostly vaporized leaving a brown hard residue.  The Dow stuff never looked or behaved any different right up to the 550 degree limit of my oven.

I ruined a set of brand new pads because the parts counter man told me that was the correct stuff.  Stupid jerk.  One look at the MSDS afterwards confirmed my suspicions.  The oven test was the nail in the coffin.

Cheers,

Huh?  Geez, I've been using Sil-Glyde for years on all of my vehicles' brakes with excellent results (well, except for the CB550).  Also, the stuff still looked pretty good inside my caliper from the last time I changed the pads.  OK, that was only about 1000 miles ago, and frankly the brakes don't work that well, so maybe the temps never got high enough to melt it (because they were "lubed"?)

I guess there's no arguing with your logic, TT.  You have done the test, and proven the result, so it is indisputable.  But dammit, the product is even called "Sil-Glyde Brake Lubricant", and is openly advertised to "Stop Pad Squeal" right on the package:

http://www.ipdusa.com/version.asp?strPageHistory=category&numSearchStartRecord=0&strParents=202,706&P_ID=248&CAT_ID=706&V_ID=669

This is EXTREMELY discomforting, as a simple search for Sil-Glyde on Google will show that there are tons of people out there who swear by this stuff (kinda like I used to be -- yesterday).

Do you really think it is possible that the stuff got to over 300F and leaked all over my pads within the 5 minutes I test-rode it?  Granted, I did a couple of hard stops to try and bed the pads.  Also, the pads were not brand new, but I sanded them to down to remove glazing and any surface contaminants.  When I stopped, the rotor was hot to the touch, but I was able to touch it without getting any blisters.

Also, consider that I was careful to lube sparingly as needed and to avoid getting the lube anywhere near the braking surface.

So, since I'm going to try some new organic pads, I might as well use the Dow pure silicone grease as you suggest.  Is there anyplace where I can walk in and buy the stuff?

[TwoTired]

But dammit, the product is even called "Sil-Glyde Brake Lubricant", and is openly advertised to "Stop Pad Squeal" right on the package:

Oh, it'll stop pad squeal, alright.  So, will paraffin and a squirt of 3 in 1.   I, too, was hoodwinked by marketing and sales techniques.  And, a persuasive parts counterman. Stupid jerk.

This is EXTREMELY discomforting, as a simple search for Sil-Glyde on Google will show that there are tons of people out there who swear by this stuff (kinda like I used to be -- yesterday).

Funny.  I swear AT it.   
It does work pretty well on car door hinges and slider gizmos that won't see temps above 150 F, or so.

Do you really think it is possible that the stuff got to over 300F and leaked all over my pads within the 5 minutes I test-rode it?

No, it took longer than 5 minutes for me.  But you had that on longer than 5 minutes, you reported 1000 miles of use.  The steel disc is porous to some degree, and lubrication molecules fit into these pores.  I had to flush/soak my rotors in solvent many times to reduce the lube content.   Silicone is extremely tenacious stuff and doesn't dissolve in anything.  The Silglyde base carrier flowed right to the pad and into the disc, bringing silicone with it.  The petro stuff either burned off or got flushed, leaving nice slippery silicone behind.  (and a loudly cursing operator.)  The brake disc will get over 300 F if they are working properly and with repeated heavy use.  Hot metal doesn't smoke with such heat, but contaminants will.  The smoke looked just like what I saw in the oven test.  This occurred with my break-in stop/stress tests and Silglyde was dripping from the caliper body.
So, after flushing the disc and new pads (and using the Dow product), I took it out and did the break-in speed stop tests.  Just when they really started to grab well, then they started to get worse.  The heated disc brought more lube to the surface of the disc and re-lubed the new pads!  But, there were no drips from the caliper this time!
I cleaned/flushed the disc again as well as the new pads, and used a belt sander to remove about a 1/6" thickness from the pad.  The break in testing was better, but there was still a noticeable change after the they started to work really well.  It took three or four flushings and heat cycles to get the disc reconditioned. (I didn't want to EVER lose braking force when I needed it most during some emergency stop in the future.)  I then put in new pads, broke them in, and with only an SS Line upgrade, I can squall the front tire with the brake lever.  Gotta squeeze hard (like when adrenaline flows), but it does it.  It's kind of an old Continental on there, so traction isn't comparable to a new Metzler.  But, this bike has the big Vetter IV for more weight transfer to the front, too.  ...But, I digress.

Also, consider that I was careful to lube sparingly as needed and to avoid getting the lube anywhere near the braking surface.

Absolutely the right thing to do.  The grease is not meant for it's lubrication properties in this application.  It is simply a barrier to keep atmospheric contaminants, water, and oxygen away from corrodable metal parts.  Pure silicone grease isn't creepy. Well, from a physical stand point. (It does seem unearthly.)  But, Silglyde definitely is creepy, particularly when hot.

So, since I'm going to try some new organic pads, I might as well use the Dow pure silicone grease as you suggest.  Is there anyplace where I can walk in and buy the stuff?

I got mine at an industrial supply distributor.  I called around first.

A word or two about pads.
The sintered metal pads help remove heat away from the disc through the pads.  Some thought about where this heat transfers to, is in order.  The Honda caliper is not the best heat radiating component for this job.  In fact, you can make a good argument for NOT putting the heat into the caliper piston and the brake fluid.  For this application, high metal content pads are not the best choice.  I was surprised when the stock Honda pads had more metal content than the originals I took off the bike due to contamination.  I can't explain why Honda changed the friction pad composition.  But, I speculate that is wasn't an engineering decision.

Cheers,

[MoTo-BunnY]

Here is a guy on feeBay selling the Dow High Vacuum Grease for $15 a tube, 'Buy It Now'. (has like a dozen tubes of it, too)

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&Item=270209207339




Any credit my way for first suggesting it might be 'grease creep' into the brake pads?   *sniff*          lol     


Hope u get your brakes fixed up - I also had a parts counter guy tell me to use the wrong stuff and ended up having to get new brake pads after they got well "lubed" by the junk grease (that was really expensive, too) - then I did the research here and found out about the Dow grease.

I will be asking the SOHC4 forums FIRST and NOT the parts counter guy, in the future.  . . .   

[turboguzzi]

it's pretty simple:

dual disc setup - 14mm M/C
single disc        - 1/2" M/C

Checked plenty of M/C's and they all have pretty much the same pivot to cylinder distance, hence same leverage.

Ferodo Platinum FDB119P pads from Vintage Brake

Filed the pads around so they are a rattle fix in the caliper.

No grease

Works a treat, my CB500 does stopies (double disc setup)

Last two tips:

Unscrew the freeplay screw that limits arm freeplay and push on the caliper to check that the fluid does get back to the M/C

Check that the caliper body is parallel to the disc surface. If not, shim with thin washers in the three mounting bolts or file the bolts bosses on the fork slider till it is.

TG

[edbikerii]

Here is a guy on feeBay selling the Dow High Vacuum Grease for $15 a tube, 'Buy It Now'. (has like a dozen tubes of it, too)

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&Item=270209207339




Any credit my way for first suggesting it might be 'grease creep' into the brake pads?   *sniff*          lol     


Hope u get your brakes fixed up - I also had a parts counter guy tell me to use the wrong stuff and ended up having to get new brake pads after they got well "lubed" but the junk grease (that was really expensive, too) - then I did the research here and found out about the Dow grease.

I will be asking the SOHC4 forums FIRST and NOT the parts counter guy, in the future.  . . .   

yes, MotoBunny, I noticed that you posted it here first!!!

Thanks for the ebay link, too.

I guess you had better luck than TT with respect to soaking/cleaning lube from the disc.  I'm going to the garage tonight to pull the caliper, clean out all the lube, and soak the heck out of the rotor with brake cleaner.  Then I'll lightly sand the rotor and pads again, and put it all back together.  When I get my hands on the pure silicone I'll pop off the caliper and lube it up.

[MoTo-BunnY]

yes, MotoBunny, I noticed that you posted it here first!!!

Thanks for the ebay link, too.

I guess you had better luck than TT with respect to soaking/cleaning lube from the disc.  I'm going to the garage tonight to pull the caliper, clean out all the lube, and soak the heck out of the rotor with brake cleaner.  Then I'll lightly sand the rotor and pads again, and put it all back together.  When I get my hands on the pure silicone I'll pop off the caliper and lube it up.

he he . .  .just playin!   though, I do have to say its nice knowing I have learned a thing or two from these forums!   

I actually had to end up replacing the pads with new ones (they were pretty worn down, anyways, as well as 'lubed') and then I did the aforementioned pumice-bar sanding, wiping down the disc with alcohol solvent several times (between sandings) with fresh paper towels. I don't think the previous junk grease I used previously had any silicone in it, though?.  . . . . silicone is tenacious! When I used that Dow grease, you can tell how persistent it was and ended up all over the place. (DON'T get it on your glasses unless you want to see smears and streaks on your lenses for weeks afterwards, no matter how many times you clean them!)   

[Chicago550]

You can also get
a free sample of the Dow Vacuum Grease directly from Dow. I just sent in for my sample I'm hoping that they send an entire tube

http://www.dowcorning.com/applications/search/default.aspx?R=112EN

[hymodyne]

Is anyone using the MC pictured if the first post with a dual front disc arrangement?

Reservoir capacity sufficient?

Hym