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Rear brake locked up?

  • Thread starter Thread starter GS650E_81
  • Start date Start date
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GS650E_81

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I took my rear tire off to replace the sprocket and tire. When putting the caliper back on the rotor the pads wouldn't separate. I had to force them apart to seat on the rotor. Now the rear tire won't spin at all. Am I doing something wrong?
 
Take it off and push the piston in with a c-clamp.
Put it together and pump the brake until it gets stiff.
 
Hi,

You can leave the pads in if you are careful not to damage them while you force them apart. Use something to cover the pads.

What maintenance have you done to the brake system? Have you replaced the brake fluid (bled the lines until all the old fluid is gone)? Have you rebuilt the calipers or master cylinder? These are all very important tasks that must be addressed. Don't ride on 30 year old brakes.


Thank you for your indulgence,

BassCliff
 
Are the proper washers on the bolts..if not the bolt can screw in too far and jam against thr rotors.
 
chuck hahn said:
Are the proper washers on the bolts..if not the bolt can screw in too far and jam against thr rotors.
Click to expand...

My bolts don't appear to have any washers and I checked to see if they were hitting the rotor and they are not.

The pads appear to be locked together hard from the top looking down. I will try and get them out and try again.


I really didn't want to have to bleed the system and rebuild the calipers, but I guess I better. Looks like I won't be riding this summer :|
 
Pry them open off the rotor and just pull them apart and clean the entire caliper and reassemble it. Take the seals out carefully and clean them. I use my fingernail to gently go around and scrape them clean from any stuck on gunk..then wash them with some hot soapy water and towel dry them. Then use a dremel and the little wire brush and clean the groove the seal goes into. The common problem is that scale builds up around and behind the seals in the grooves. This creates the need for something to be displaced and that would be the seal. This pressure causes the seals to gorilla grip the piston and your at the point you are now. If you simply disassemble it and clean the seals and grooves youll most likely have good brakes again..Its only a hr or so worth of work. Be sure tht you smear a bit of brake fluid on the seals and pistons before you slip them back in.
 
chuck hahn said:
Pry them open off the rotor and just pull them apart and clean the entire caliper and reassemble it. Take the seals out carefully and clean them. I use my fingernail to gently go around and scrape them clean from any stuck on gunk..then wash them with some hot soapy water and towel dry them. Then use a dremel and the little wire brush and clean the groove the seal goes into. The common problem is that scale builds up around and behind the seals in the grooves. This creates the need for something to be displaced and that would be the seal. This pressure causes the seals to gorilla grip the piston and your at the point you are now. If you simply disassemble it and clean the seals and grooves youll most likely have good brakes again..Its only a hr or so worth of work. Be sure tht you smear a bit of brake fluid on the seals and pistons before you slip them back in.
Click to expand...

Any way to get the piston out without using compressed air? As I don't have a air compressor. Might as well do a complete cleaning if I am going to go this far..
 
Take the caliper off the rotor but DONT break the banjo bolts. Remove the pads and the pistons will now be wide open. Get a piece of about 1/2 inch thick wood and a few other thinner pieces..like say 1/8 strap steel shims. Next insert the wood with a shim or two ( whatever fits in the caliper) then pump the foot lever and the hydraulic pressure will push the pistons out to the shims. Remove the 1/8 inch pieces and pump some more. The idea is to get the pistons out as far as you can without actually dislodging them from the caliper. Then you remove the caliper from the brake line, undo the 2 allen heads that hold the 2 halves together and you can wrap something around the pistons to prevent any scars and use some channel locks to get them the rest of the way out. You can grip them by the very end just above the groove the dust boots go in also and kinda twist and pull out at the same time. You just dont want to scar anything below that groove though.
 
I probably should add that the pistons arent that deep in the calipers..maybe around 3/4 inch or so. guage how far your getting them out and make a call as to how far is enough..then grip them and twist them the rest of the way out.
 
I loosened up the bolts that hold the caliper to the rotor. That seemed to work. The wheel would spin freely.

The problem is I was riding Saturday morning and the back brake went out. I looked at the caliper. One of the bolts is missing!

I assume since I cannot tighten them down all the way one vibrated out. So now I think I may have to lock-tite them so they stick? Confused as to why when I tighten down the caliper snug, the wheel does not move...
 
I would figure that out before riding the bike again.

Riding around with intentionally loose brake parts is qualifying yourself for a Darwin Award. :eek:

.
 
Dude, fix the bike before you wind up dead.:(

Pull off the caliper and then remove the pads. Hold the caliper in your hand and gently pump the brake pedal and watch the pistons come out. Try to get both pistons to come out equally (push the one that is coming out faster back in some. In the end you want both pistons to pop out of their bores at roughly the same time. Brake fluid will go everywhere so be ready for that. If one piston is still in the bore, carefully pry it out - use two screwdrivers at 180 degrees from each other around the piston, prying up in the dust boot groove.

Once you get the piston out inspect all the parts and clean out the crud. I strongly advise you to take the master cylinder apart too, and replace the brake line. The entire job will only take about 1/2 day assuming you gather all the parts and tools together first.

Good luck and please be safe.
 
Nessism said:
Dude, fix the bike before you wind up dead.:(

Pull off the caliper and then remove the pads. Hold the caliper in your hand and gently pump the brake pedal and watch the pistons come out. Try to get both pistons to come out equally (push the one that is coming out faster back in some. In the end you want both pistons to pop out of their bores at roughly the same time. Brake fluid will go everywhere so be ready for that. If one piston is still in the bore, carefully pry it out - use two screwdrivers at 180 degrees from each other around the piston, prying up in the dust boot groove.

Once you get the piston out inspect all the parts and clean out the crud. I strongly advise you to take the master cylinder apart too, and replace the brake line. The entire job will only take about 1/2 day assuming you gather all the parts and tools together first.

Good luck and please be safe.
Click to expand...

Thanks.

Advised I am brand new to working on brake systems. Can I just order a replacement brake line from gssuzuki.com or something like that? Or will any brake line work?

I know SS brake line is supposed to be good as well. Can that be used for the rear brake?

I am going to take the caliper apart tonight and see whats going on.

Thanks for your input.
 
Also, does anyone have a picture of the rear master cylinder with the lid off? Mine has a rubber housing but it appears to be dirty and is sitting on top of the brake fluid. Is brake fluid suppose to be in the rubber housing or under it?

Noob :D
 
GS650E_81 said:
Also, does anyone have a picture of the rear master cylinder with the lid off? Mine has a rubber housing but it appears to be dirty and is sitting on top of the brake fluid. Is brake fluid suppose to be in the rubber housing or under it?

Noob :D
Click to expand...
The master cylinder itself does not have a "lid", but the reservoir does. :o

Yes, there is a diaphragm inside that somewhat seals the fluid from the air, otherwise the fluid would keep absorbing all the moisture out of the air, contaminating itself.

The master cylinder is the part that is at the lower end of the hose that comes out of the reservoir.

Usually, the only thing necessary on the reservoir is a good cleaning, unless it is physically damaged, then it needs to be replaced.
Any rebuilding" is going to happen in the master cylinder, where you will replace the piston, spring and seals.

You would probably be doing yourself a favor if you also got a rebuild kit for the caliper, but take it apart first, to see if you might also need to order a piston.

To answer your other questions:
Yes, you can get a new brake line from G&S Suzuki or any of the other vendors that we use.

A stainless line will also work, but is a bit more money.

Your issue with the brakes only working with the bolts loose is probably due to not having axle spacers installed correctly. If the spacers are not in the correct order, the brake disk will not be centered in the slot in the caliper, causing it to drag or bind. Find out which way the caliper needs to move, and how much, you will probably find a spacer that thick that you have in the wrong place.

.
 
Steve said:
The master cylinder itself does not have a "lid", but the reservoir does. :o

Yes, there is a diaphragm inside that somewhat seals the fluid from the air, otherwise the fluid would keep absorbing all the moisture out of the air, contaminating itself.

The master cylinder is the part that is at the lower end of the hose that comes out of the reservoir.

Usually, the only thing necessary on the reservoir is a good cleaning, unless it is physically damaged, then it needs to be replaced.
Any rebuilding" is going to happen in the master cylinder, where you will replace the piston, spring and seals.

You would probably be doing yourself a favor if you also got a rebuild kit for the caliper, but take it apart first, to see if you might also need to order a piston.

To answer your other questions:
Yes, you can get a new brake line from G&S Suzuki or any of the other vendors that we use.

A stainless line will also work, but is a bit more money.

Your issue with the brakes only working with the bolts loose is probably due to not having axle spacers installed correctly. If the spacers are not in the correct order, the brake disk will not be centered in the slot in the caliper, causing it to drag or bind. Find out which way the caliper needs to move, and how much, you will probably find a spacer that thick that you have in the wrong place.

.
Click to expand...

Thanks Steve. I think you are right. I forgot to take a picture of the caliper and rear axle before replacing the tire.

I have a Clymer manual but if I remember when looking at it, I got rather confused.

I will take another look at it.
 
One of the pistons is fully erect, but I cannot get it to come back down. The other piston will go up and down freely. Is there a way to get a stuck piston to go back into the caliper?

I took off the rubber housing on the piston so I know its not stuck on the rubber.
 
This is in the caliper?

Take the piston completely OUT. Take out the o-ring that seals against it, clean the groove that the o-ring sits in. Also clean out all the gunk behind the piston. It might be best to change the o-rings, too, but you will have to decide whether you want money in your wallet or good brakes on the bike.

Yeah, if you just want to get the piston back in, you can use a c-clamp to push it in.

.
 
GS650E_81 said:
One of the pistons is fully erect, but I cannot get it to come back down. The other piston will go up and down freely. Is there a way to get a stuck piston to go back into the caliper?

I took off the rubber housing on the piston so I know its not stuck on the rubber.
Click to expand...

It's simple to get the piston where it belongs. Follow these steps carefully...

1) Remove both pistons from the caliper

2) Clean both pistons and look for pits in the chrome (replace if damaged)

3) Order new piston seals and brake line

4) Remove master cylinder and tear it down. Inspect cylinder bore carefully for corrosion damage and replace as necessary

5) Order a new master cylinder kit

6) Reinstall new seals in caliper and master cylinder, and reassembly everything with your new brake line

7) Bleed brakes and ride happy
 
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