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Main Area => General GS500 Discussion => Topic started by: Toner on April 24, 2015, 03:23:18 PM

Title: Is it ok to lift the rear caliper off the disc to push the pistons in? UPDATE!
Post by: Toner on April 24, 2015, 03:23:18 PM
Is it ok to lift the rear caliper off the disc to push the pistons in?
Was going to put some new pads in the rear caliper but I couldn't slip them in as the pads were worn down to pretty much the metal and the pistons were out too far so I bought some of these:

(http://i.imgur.com/i5aXYFW.jpg)
Piston Pad Spreader/Seperator for Brakes.

My plan is to remove the mounting bolts and the torque arm nuts and lift the caliper off the disc being careful not to pinch the hose.
Then use the tool to push the pistons back home. 
Probably take the cap off the reservoir too.

Do you think this is an ok plan?

Also, not going to change the hoses and clean up the caliper, pistons etc just now but I was reading the manual and it said in order to pump the pistons out with the brake pedal, you should loosen banjo bolt on the caliper and then re-tighten it lightly before you start pumping them out. Anyone know why this is?
Title: Re: Is it ok to lift the rear caliper off the disc to push the pistons in?
Post by: Iarn on April 24, 2015, 03:38:21 PM
Sorry, I may have misunderstood. You couldn't do it by just removing the cap off the rear caliper?
Title: Re: Is it ok to lift the rear caliper off the disc to push the pistons in?
Post by: Toner on April 24, 2015, 04:01:17 PM
oh sure I remove the caliper cap but there isn't enough space to get that tool in because the wheel or some other bike part is in the way. If I could get it off the disc I could use it.
Title: Re: Is it ok to lift the rear caliper off the disc to push the pistons in?
Post by: Slack on April 24, 2015, 04:03:27 PM
Never seen one of those tools before. Everyone else just uses a c-clamp. You can leave the old brake pad in while compressing the piston so as not to mar the piston surface. Depending upon the price you paid for that thing you may want to return it. C-clamps are multi functional.

Yes, your plan is exactly how you change brake pads. Except, no need to remove the torque arm bolts as I recall, just loosen them and swing the caliper up.

Don't loosen the banjo bolt. You will introduce air into the system and have to bleed your brakes.
Title: Re: Is it ok to lift the rear caliper off the disc to push the pistons in?
Post by: Toner on April 24, 2015, 04:20:57 PM
Cool, thanks! so need to remove the torque arm bolts.

The tool wasn't expensive - cost me a tenner on ebay. Don't have any c-clamps and the quick grips I used on the front wouldn't fit in the rear . Didn't think c-clamps would fit either. 

Won't be removing the banjo bolts just yet though I plan on getting a new steel hose to match the front you all helped me put on recently.  :)
Title: Re: Is it ok to lift the rear caliper off the disc to push the pistons in?
Post by: MeeLee on April 24, 2015, 11:00:02 PM
I just use the wheel itself.
The calipers supposed to open pretty easy.
Tilt the wheel under an angle, and the disc will push them open enough to put a screw driver in.

On mine, I can just open the brakepads with my finger as soon as my index finger fits in between them.

I see no reason for a tool, unless the pads are locked; and if that's the case, the brake unit may need replacement.
Title: Re: Is it ok to lift the rear caliper off the disc to push the pistons in? UPDATE!
Post by: Toner on April 25, 2015, 05:17:24 AM
Just putting everything back together now with new pads. I had to remove one torque arm bolt to pull/turn the caliper out a bit and get that tool in to push the pistons home.

One quick question though: 
My bike didn't come with brake plates so I managed to buy some off ebay. Supposedly they reduce squeal.

But does anyone know if there is a certain way they go on or can I put any plate on any pad?

(http://i.imgur.com/q0kOWqX.jpg)

I'm just going to assume the left one is the inner one and the right the outer one in this pic...or maybe it doesn't make a diff.
Title: Re: Is it ok to lift the rear caliper off the disc to push the pistons in? UPDATE!
Post by: Suzuki Stevo on April 25, 2015, 06:15:55 AM
I'm not sure how the shims go? But once you find out..smear a thin later of this Goo on them (both sides) and you will never hear another squeal, brake squealing is caused by the back of the pads vibrating against the pistons, NOT the brake pad against the rotor.

(http://home.comcast.net/~stykers/m77.jpg)
Title: Re: Is it ok to lift the rear caliper off the disc to push the pistons in? UPDATE!
Post by: The Buddha on April 25, 2015, 07:36:32 AM
You dont need that tool. You can do it with a broad blade screwdriver.
BTW, if you see brake fluid come out of where you push it in, the slave cylinder needs to be rebuilt.
Cool.
Buddha.
Title: Re: Is it ok to lift the rear caliper off the disc to push the pistons in? UPDATE!
Post by: gsJack on April 25, 2015, 07:41:50 AM
Rear brake squeal has come up a lot of times in the 15 years and 180k miles I've ridden the GS500s with no really definative answer.  If Stevo's Goo works for you by all means use it.  I had a lot of brake squeal on my 97 GS back when it was new and after the pads and rotor both wore in to a glaze, varying amounts for a while after that, and none in recent years.

At one time there was a forum thread about rear wheel alignment affect on brake squeal and many agreed it did matter including myself although it shouldn't matter in theory based on the design which locates the caliper off of the axle.  A little change in alignment eliminated it a couple times for me.

Regarding which way the pad shims go, the parts fiches show the closed side forward opposite of your intended way if that means anything.  I do recall once years ago when the brake was squealing loudly I reversed them and all but eliminated the squeal for a while but could be I just tightened up the parts in a different sequence affecting squeal.

http://www.shspowersports.com/fiche_image_popup.asp?fveh=2102&section=92709&year=2001&make=SUZUKI&category=Motorcycles&dc=3378&name=REAR+CALIPER
Title: Re: Is it ok to lift the rear caliper off the disc to push the pistons in? UPDATE!
Post by: Toner on April 26, 2015, 11:35:45 AM
Thanks guys, had to head off yesterday so I couldn't respond.

Found a pic in the Haynes manual of the brake plates and yeah the left one in the image I posted is on the inner pad (closest the wheel). Don't know if it makes a difference but it might.

Dabbed a little copper grease between the plate and the pad which I think might have the same effect as that Honda paste Stevo posted although I didn't do both sides of the plate.No squeal today though!  :)

The spreader tool worked well although it would be nice if I didn't have to pull the caliper off the torque arm.

No brake fluid came of the calipers though I'd say they are due for some new seals and a clean-up. Did the front recently with the help from the forum after the brakes seized and discovered the outer seals had disintegrated or become one with the pistons. Doubt the previous owner ever touched them

Gonna replace the hose soon so I'll do it then. Buddha, when you say "slave cylinder" does that cover both cylinders in the calliper or just one in particular?

It was time to tighten my chain today and I wanted to use a chain alignment tool I bought (not a laser one) but I couldn't get the chain guard off as the previous owner had stripped one of the bolts.

Tightened the chain and aligned it as best I can but I never trust those markings, always seems off so I'm gonna order some bolt/screw etxractor bits. Tried to cut a groove with a dremel but I just made a mess.



Thanks again for all the help guys.
Title: Re: Is it ok to lift the rear caliper off the disc to push the pistons in? UPDATE!
Post by: Slack on April 26, 2015, 12:30:32 PM
You can use a string to align the rear wheel. Tape it to the tread of the rear tire a few inches after the contact patch. Then have a mate hold the bike upright and center the handle bars. You lay down at the front and pull the string tight against the rear wheel, which shows you it's relation to the front wheel, and gives you a guide to center the rear wheel by.
Title: Re: Is it ok to lift the rear caliper off the disc to push the pistons in? UPDATE!
Post by: Toner on April 26, 2015, 02:30:47 PM
Good idea with the string method. Just found a video demo: