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View Full Version : Seized brakes, suggestions please. Divvy 900.



ELIMINATOR
08-04-07, 06:02
One piston "appears" to have bits of rubber seal protruding from the caliper around th outside of the piston. I can imagine that this is going to be a hard job to remove.

I was thinking of blocking off the working piston & pumping the brakes. If that doesn't work, then removing the caliper, and heating it in hot water, hoping that the aluminium expands faster then steel & separates?

Ideas anyone?

Tommo
08-04-07, 07:30
Remove the calliper from the bike but leave the brake pipe on. Then get a smallish G clamp and a thin piece of wood and fit to over the calliper and the piston that is still free use the bit of wood to protect the piston from being damaged by the clamp. Next start to pump the brake lever slowly this will in turn start to push out the piston that is stuck. You will have to bleed the brakes once reassembled. Note you will most likely find that it is only the outside seal (dust seal) that is buggerd but my advise would be to replace both the Dust and Oil seals making sure that the recess in the calliper where the dust seal fits is perfectly cleaned out all the way around.

ELIMINATOR
21-04-07, 12:12
All done, including removing all the corossion & flaky paint, & repainting. New seals all round, pads now release:bounce1

ELIMINATOR
28-04-07, 20:07
Front calipers are a pig. Got the smaller piston out, cleaned the corossion out from ther dust seal. The larger piston is, I feel clear of the brake fluid seal, but is stuck about 4mm short of popping out. The dust seal has come out in places & making it stick. With the smaller piston in place, & clamped, the bigger piston just pisses fluid & refuses to shift.

I might have to take it to work, & try blowing it out with hydraulic pressure at work, hopefully 40barg may do it:rolleyes:

cookie
28-04-07, 21:45
put the free piston back in, chock it so it can't come out, and blow the siezed one out with an air line.

be careful ;)

AndyT
28-04-07, 22:01
Brakes are a real pain. Most people (me included) only look at them when the pads are down to metal. I have a similar problem to you in trhat the rear brake on my Honda Shuttle was siezed. I only detected this by noticing that the auto transmission was changing down at the slightest hint of an incline. Touching the wheel (very warm) confirmed my thoughts.

I stripped down the brake without splitting the piston from the caliper and found that one of the Floating caliper rods had siezed. I removed , emeried down and greased but open reassembly I couldn't get the piston back into the caliper as far as I needed (infact I am convinced it was just about fully home using a "Puller" with a socket to force the piston back in enough to clear the pads). I had to omit fitting the anti squeel backing plates to get the piston to clear the pads. I recon that this must have been dodgy for quite some time. I had to do the front brakes when I bought the car as whoever had fitted them (Arnold Clark:rolleyes: ), had not done so correctly and force was ionly being applied to one side of the disc causing them to warp and one side wear down rapidly.

Anyway hopefully all is well now as brakes re quite importqant to work when you need them;)

By the way when you take your caliper to work hydraulic pressure is a better meduium than air pressure as it is incompressible and it won't fly out as far when it goes:thumb

Straypuss
29-04-07, 08:32
Andy, I take it thatyou have discs on the back and the handbrake is operated by a lever built into the caliper. These are very prone to seizure and failure of h/b to work. The pistons usually require to be 'wound' back in ie the h/b adjustment is taken care of by a fine thread inside you cant just force the pistons back. there are tools but you can do it by turning the piston (slot/s in it?) and pushing it back...if you are creative with tyre levers and screwdrivers! a real pain when fitting new pads to an old car. Recon calipers are the only way sometimes but they are cheaper nowadays.

ELIMINATOR
29-04-07, 10:18
By the way when you take your caliper to work hydraulic pressure is a better meduium than air pressure as it is incompressible and it won't fly out as far when it goes


That's why I'm doing it this way, safer, less likely to cause damage.

cookie
29-04-07, 11:19
That's why I'm doing it this way, safer, less likely to cause damage.

you will need to seal it all up better though.

Kaister
29-04-07, 11:23
as cookie says - once you've got all the other pistons out - grease them and push them back in - then clamp em with a ....clamp.

the last piston sounds like its rocked sideways and is jammed.

push it back in - then pump it out with brake fluid - cos thats hydraulic too :thumb :)

AndyT
29-04-07, 11:27
Andy, I take it thatyou have discs on the back and the handbrake is operated by a lever built into the caliper. These are very prone to seizure and failure of h/b to work. The pistons usually require to be 'wound' back in ie the h/b adjustment is taken care of by a fine thread inside you cant just force the pistons back. there are tools but you can do it by turning the piston (slot/s in it?) and pushing it back...if you are creative with tyre levers and screwdrivers! a real pain when fitting new pads to an old car. Recon calipers are the only way sometimes but they are cheaper nowadays.

Nothing so simple for the Honda;) The hand brake is indeed cable operated but works on a set of shoes internal to the disc hub (if that makes sense). The disc spins freely with the disc pads removed and the hand brake off. I just can't seem to get the piston far enough back into its cylinder to allow it to fit over the pads with the anti squeel plates fitted.

Since I bought the car 3 out of the 4 brakes have been problematic I think I should look at the 4th whilst i'm at it as the weather is not so sunny today:(

Thanks for the tip anyway - just about to respond to you PM;)

regards

Andy

ELIMINATOR
29-04-07, 15:47
push it back in - then pump it out with brake fluid - cos thats hydraulic too
__________________



The tank at work can pump continuously, probably at about 100 times the volume.

ELIMINATOR
10-05-07, 09:41
All sorted before last weekend, all OK now:D :clap :bounce1

Realising how simple it actually is to strip the brakes completely, why is this rated as a "4 spanner" job in the Haynes manual? Other jobs look more complex to me, or is it my naturally pessimistic nature?

By comparison, how would changing the rear FD bearing rate in the Haynes manual? Yes, I haven't got one.

ELIMINATOR
04-07-07, 17:30
It wasn't!! One of the pistons weeped as it was pitted.I have had three pistons sent to me by a brake supplier, all wrong. I received this e-mail today:eek: :blast :tears

"Right, I have now managed to get to the bottom of this, by all accounts the piston I sent you will fit Honda, Kawasaki, Suzuki, and some Yamaha’s that call for that size, however Yamaha in their wisdom have altered some models to take a marginally smaller piston 30.06 from what I have been told that this only applies to certain few Yamaha models and the rest conform to piston size sent, they have also altered piston dust seal from 2mm thick to 1.6mm nobody can understand why, but there it is, One of my suppliers is currently having some of these 30.06mm pistons made but there is only a small requirement for them they were unable to tell me yesterday when these will be available but I suspect it will be a couple of months, so send the one back and I will credit you, sorry it is not better news but Yamaha HAVE to be different all mirrors have 10mm right hand thread for all Japanese makes and models above 125cc except Yamaha who have 1 right hand thread and 1 left hand thread."

FFS

ELIMINATOR
06-07-07, 21:54
Also ordered caliper from breakers...........................pistons were scored.

Replacement caliper was sent in the post.......it got lost.:blast

Two new pistons arrived in the post yesterday...........both the wrong size.:blast :thedummy


Breaker said they will send me two genuine Yamaha pistons:thumb2 I shall pray.