Rear brake refurbished STILL NOT ENOUGH BITE

[Kara25]

Hello everyone. During those crazy lockdown times we all live in I decided to dive into my GS550E rear brake system in anticipation of summer and freedom at last. I removed the caliper and the master cylinder cleaned them meticulously using vinegar baths and compressed air. Rebuilded both of them with TOURMAX rebuilt kits. Also Installed SS brake line from VENHILL. I bled the system but what I have now is the following. I press the pedal it goes down a little bit and THEN pushes the pistons out and if I release it and push it again quickly it gets WAY stiffer and has more bite. I let it sit for five minutes the sponginess returns. Any ideas as to what’s going on? I also Zip tied the pedal down for the night because I remember months ago I saw this tip on another thread.! I really like using the rear to control the bike bcs the place I live has very narrow and small backroads.! Thanks in andvance!

[Rob S.]

...if I release it and push it again quickly it gets WAY stiffer and has more bite.

Sounds like there's still air in the system.

[Kara25]

Thanks Rob the thought crossed my mind too but I can’t understand how is it possible to still have bubbles after all that bleeding. That’s why I zip tied the pedal in a last ditch attempt to remove them overnight!

[Baatfam]

Air is surely a possible, but also see if the pistons are pulling back further than normal.
The piston may not be sliding smoothly in the seal, the seal pulls it back.

Just a thought. Seen it more than once on the fronts.

Don't know anything about TOURMAX rebuilt kits, as OEM is generally the way to go.

[Grimly]

The rear caliper can be awkward to get rid of the last bubble of air.
Sometimes I've had to take it off the bike and hold it in various positions to coax that bubble to the bleed nipple(s)

[fastbysuzuki]

Don't know anything about TOURMAX rebuilt kits, as OEM is generally the way to go.

IMO tourmax are good quality and made in Japan have them on my 850 braking system for years with no problems

[Baatfam]

IMO tourmax are good quality and made in Japan have them on my 850 braking system for years with no problems

Good to know, thanks....

[Nessism]

The problem is the aftermarket seal parts. They are too tight and won't allow the piston to move out closer to the disc the way they should. You had the right idea about pumping up the system and locking the pedal down over night but if the seals are "really tight" even that doesn't work. I'd try again, pumping up the system as much as you can. Or better yet, get OEM Suzuki parts.

[Kara25]

Thank you everyone for your insight.Gonna have a cup of coffee and see if i have any difference after zip/tying the pedal overnight.Reporting back later!

[Kara25]

UPDATE. Big improvement with zip tie overnight trick. Initial sponginess before movement of pistons is gone now the bike stops depending the power you use on the pedal. Still not locking the wheel though. I think I am expecting too much from those calipers. Also thinking of cleaning the disc using green scotch brite cause they seem to have past brake pad residue on them EDIT: during refurbish I DID NOT CHANGE brake pads cause they seemed beefy enough with still lots of meat left on them.

[Baatfam]

UPDATE. Big improvement with zip tie overnight trick. Initial sponginess before movement of pistons is gone now the bike stops depending the power you use on the pedal. Still not locking the wheel though. I think I am expecting too much from those calipers. Also thinking of cleaning the disc using green scotch brite cause they seem to have past brake pad residue on them EDIT: during refurbish I DID NOT CHANGE brake pads cause they seemed beefy enough with still lots of meat left on them.

Good. Glad you're getting there.

Consider changing the pads anyway. New pads can make a significant difference, especially if yours are 25+ years old.

[Gorminrider]

It should lock the rear wheel.
If they are oily-contaminated, solvents may drive the contamination INTO the pad. but, Alcohol(methyl or ethyl or iso for backrub) will take grunge off your disk without leaving any residue.
You can try to sand or file the pads if they are really bad. Use flat backing-block for sandpaper to keep the pads flat.
extra complications
If there are deep grooves in the pad, filing or sanding will remove them ..so, the gouged brake disk will need time to re-imprint them for full stopping power.
IF your pads are not perfectly aligning to the disk, (a little wedge-shaped) fix this, or be careful to A) mark the pads per side and B)keep the same tilt when sanding-filing.
SAFETY First: wear a mask for dust, vacuum during and after...

[Kara25]

So I think I goofed up on buying new pads and be done with the overhaul. A quick search on the internet pointed out that those goldfren type 076 pads will fit my rear caliper. Upon trying to install them they are not long enough for the two holes to match the guides on the caliper that the pads travel upon. �� Any good recommendation for pads that will surely fit on a 550E rear??

[cowboyup3371]

You can get pads at Z1 but can you post a picture of how the pads you have are sitting in the caliper?

[Kara25]

I would have posted pics cowboy but I am getting constant errors when I try to upload from my iPhone.the pads are shorter hole to hole from the ones that are already on the bike. What a stupid mistake now I am stuck with brand new pads that I can’t use. What *@%^$*@%^$*@%^$*@%^$es me off is that their site had the GS550E in the compatibility list with those particular goldfren pads