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Replacing o-ring in front resevoir

Gregory

Gregory

Forum Mentor
Past Site Supporter
Hello All.

I have searched and not found if there is a trick to getting the resevoir O-Ring in the channel of the master cylinder body.

Mine seems to be a smidge too big.
 
Have you cleaned the groove very very well to be sure all that grey scaling is removed? Did you lube the seal with a dab of brake fluid before installation? If all of the above is good, then take your finger and run it around on the seal to get it stretched and pushed back in to the groove as good as possible. Be aware that installing the resivoir cup will take some good old fashioned pressure and wiggling to get it snapped back in. Kinda look in from the top and align the holes with the body so the screws will be real close when you get it in. Youll have to twist it a bit to line up the holes though.
 
Thanks Chuck. Actually I guess I spoke too soon. After I posted that I went back out to the shop and tried using grease to hold it in the groove. It took grease and patience...but it worked.

Now I just need to find a picture of the order that the new piston cup set goes back together....

I was waiting for quite a while on the plcae I orderd from to send me the right parts.
 
Look at any parts fiche such as at bikebandit.com or boulevard suzukis site...also click on the Mega Welcome from Bass Cliff and look for the tutorial. Search feature will undoubtedly bring up several threads..just cruise the nthreads till ya find what you need.
 
i went to basscliff's site but only found info on calipers

on the schematics, it shows the piston cup set as one fuzzy picture

i think i have most of it figured out, but not positive where the little metal disc goes
 
Look at the rubber cups...one is gonna have an imprint in it...then assemble the new kit the same way. ( am assuming your doing a full on rebuild ). Next time you disassemble something, snap a picture of the innerds. What i do is lay out a rag and lay the parts down in the order they come out and then take a picture to look at when reassembling.
 
yes full rebuild.

i definitely should have taken pics.

when i got the first kit (wrong one) i had everything laid out, easy peasy...but then i had to dissaemble and send it back ..then wait 2 weeks on the new kit... i thought i would remember but didnt.

i got the rubber on the metal plunger correctly (i think), but cant remember which end of the spring goes in first (small with rubber or large with spring end)

...and where the little brass disc goes (washer thing without hile in it)
 
Lay the parts out in the order you think is right..take a picture and post it. Then we can see what to do. Has been a long time since ive been in one. I "think" I recall the order correctly but dont want to post out of school here.
 
I do know the small end of the spring goes toward the piston...the large end rests on the shoulder inside the bore. If you test it against the piston only one end will fit into the cups recess.
 
Be SURE that you put the circlip in the inner most groove too..take a look at the end of the bore. The inner groove is for the circlip and the outer one is for the dust boot. Otherwise youll have a leaking master cylinder.
 
Swab the bore with a Qtip soaked in brake fluid...this helps the piston slide in and not grip against the dry bore walls.
 
i just came back in from trying it. didnt see that last message before i went out. no leak but no brake yet. it's not too squirty just a bubble each time i pull the lever....

so i bet i didnt get it in far enough, although the boot seemed to bottom out pretty good.

i tied the handle back and will take a look at it in the morning.

thanks again for all your help. much appreciated
 
Just ever so slightly wiggle the lver and look into the resivoir...bunch of little bubbles will escape. easiest way to do it is a power bleeder. I have a Mighty Vac. Used it just today to do brakes on an 82 Honda CB900 Custom.
 
Gregory said:
oops. i used a bit of wd40 instead
Click to expand...

Sorry, but you need to tear it all apart and clean it and start over

Any petroleum oil in the brake system is strickly forbidden. The brake system's going to lock up on you soon if there's oil in it.

Go to your auto parts store and get some silicone brake lube that is designed for O rings. They may sell it in a little $1.50 pack by the parts counter or check out, If not, the Permatex Ultra (google it) for about $6 will last you a lifetime

http://www.permatex.com/products/au...ake_Caliper_Lube_Hi-Temp_Silicone_Formula.htm (also comes in a smaller tube)

Take the MC apart, including the Resevoir O ring you greased and clean it with brake clean.

Reassemble using the silicone grease, put it on the O ring, the cup and the piston and reinstall the parts

Ask me how I know this (experience)
 
Last edited:
T...I was taught years ago doing cars that you always lube with what the part is gonna be handling..but in this case its not so critical. He can fill the resivoir and place his finger over the banjo bolt hole and pump it a bit to simply flush the master before installing the rest of the lines and stuff. Can also use compressed air to blow it all out real good. Not an OMG moment by any means..easily rectified.
 
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