Seized Caliper

[Bigtwin]

The near-side inside caliper pots (both) are solid. First time I have ever had this problem, probably due to the rubbish design of the BMW Evo calipers, with the silly metal covers that don't keep anything out; I keep them clean, and always hose off the salt etc. The bolts for those have of course seized, and the heads are made of window putty - got them out with mole wrench. Needless to say, resulted in one pad worn to the metal, while the others are barely 1/2 worn - cheers Steptoe for the reasonably priced new pads.

Anyway - any top tips of shifting the pots? They are firm in the retracted position, so no good trying to push them in. My only thought is to insert a "T" piece against the good side, braced against the caliper body on the seized side, and let the servos drive out the pots.

Problem is, using the pad with a bar (screwdriver or similar) in the middle will probably just bend/snap the pad, and I don't have anything else for the job, and no access to anything like a milling set-up to make something.

Are there any secret techniques out there? Any amazing anit-seize products that might release the pots?

Cheers all

 

[Gas'd Off]

Any amazing anit-seize products that might release the pots?

Bucket of diesel. Drop it in there for 24hrs and cross fingers
Have you got any small 'G' clamps that you could hold back the unseized pistons with? Then pull the brake lever and the seized pistons may move. That is how I push the pistons back when installing new pads. If you do that just make sure they can only move a few mm at a time otherwise they could come flying out and ricoshea(how dyou spell that!) across the workshop/garage

 

[Shep]

Using Hydraulic pressure is the safe way, but only if both pistons can be moved at the same time, i used to use a bench mounted hydraulic pump adapted from a hydraulic work bench, I've also had some success (when you can get access) in using a large Tap (threaded Type not sink/bath) screw into the open end of the piston and turn gently, this combined with a dip in diesel as previously mentioned, has saved me a few quid in the past. I've no experience of 1150 calipers so neither of the above may be applicable.

However all these are bodges really, new or reconditioned calipers, would be the sensible answer, then plenty of fresh clean cold water on the calipers after every ride to keep the salt at bay.

Shep

 

[Bigtwin]

However all these are bodges really, new or reconditioned calipers, would be the sensible answer, then plenty of fresh clean cold water on the calipers after every ride to keep the salt at bay.

Shep

Thanks - will add to the "to try" list.

Pain is this - the bike is only just 2 years old, and I am very careful about keeping them clean and washed (no solvents, just water) - this is clearly pants design for them to by stuffed already.

To cap it all, Vines did a brake check only 10 days ago. I specifically asked them to cast an eye on the pads then, just to see how they were waring; "everything's fine", they said. Clearly didn't even look at them.

 

[Mzokk]

Fresh clean water to remove salt and crud is not enough, all bikes will seize calipers if used in the winter, preventitave maintenance will save a lot of grief in the long run. The calipers need to be removed and stripped for cleaning al least every few weeks. See this thread

http://www.ukgser.com/forums/showthread.php?t=38909

 

[cookie]

will they blow out with an air line?

hydraulic pressure with a grease gun sometimes works.

if they are REALLY REALLY stuck, you can weld a bar to the piston then clamp bar in the vice & persuade the caliper off the piston with a mallet. i don't imagine bmw or brembo would approve of such measures though

BTW i've never done any preventive maintenance on any calipers on any of my bikes & i've never had one sieze

 

[Bigtwin]

Fresh clean water to remove salt and crud is not enough, all bikes will seize calipers if used in the winter, preventitave maintenance will save a lot of grief in the long run. The calipers need to be removed and stripped for cleaning al least every few weeks. See this thread

http://www.ukgser.com/forums/showthread.php?t=38909

You are joking? Stripped at least every few weeks?? Never had one go before, and been riding year round for 25+ years. And you would then have to replace the seals every time you strip to do it properly.

That would be the definition of a design fault in a braking system if that was necessary.

 

[cookie]

That would be the definition of a design fault in a braking system if that was necessary.

i quite agree



having said that, not riding them in the cold is definitely the way to go

 

[Mzokk]

You are joking? Stripped at least every few weeks?? Never had one go before, and been riding year round for 25+ years. And you would then have to replace the seals every time you strip to do it properly.

That would be the definition of a design fault in a braking system if that was necessary.

No not stripping the pistons out just taking the calipers off and cleaning them properly!!

 

[Bigtwin]

No not stripping the pistons out just taking the calipers off and cleaning them properly!!

Granted they may need a more serious clean occasionally if you are often in bad conditions, but if they are correctly installed and lubed in the first place, there is no way they should need more than washing off from week to week - I mean where I am they only salt the roads about 4 times a year - the rest is just water and road grime - which they should be about to cope with fine without intensive maintainence. If you weren't machanically minded (and if bike is in warranty anyway, home wrenching is right out) you'd have a service bill running up like a McLaren F1.

The Tokais on my GSXR went for 6 years + with just pad and fluid changes at normal intervals, water wash when salty, and a clean over when the pads were done - problem free. But then the backs were covered up, so they weren't exposed to the elements the whole time. Even my otherwise piss-poorly made Triumph never had caliper probs.

 

[(RIP) Jamie]

I lay a tyre lever across the pads I dont want to remove, then cable tie it on, then push out the free pistons with the lever and let the fluid push, clean, then replace the piston by opening the bleed nipple and pushing then back in, any pressure is passed through the bleed nipple and out.

Repeat for the other side, then other caliper, if that makes sense.

This was an annual ritual for me in the spring, it means I get new pads and the fluid is replaced, and the calipers cleaned after the winter crud build up.

But this year, everytime I get in from a ride, i hose the bike down with cold water, spray WD40 all over, then spray STP brake parts cleaner into the calipers, so it looks likes it worked, no seizing, no binding.

Ten minutes at the end of each ride may have saved me hours of faff, I'm waiting for pads via the Steptoe express, which now should only now take a hour or so, instead of it being an all dayer.

Not looking forward to cleaning the bike though

 

[pomm001]

seized brake

The easiest and safest way would be to leave the caliper connected to the brake line, put the old pad or suitable spacer on the free side between piston and disc, and slowly apply pressure via the brake lever.
Most probably only one will move out, keep it going till a good way out, clean exposed piston with clean rag and apply some clean brake fluid to the piston.

Be very carefull when using solvent cleaners on brake rubber parts, pertoleum fuels will swell the EPDM compound.

Drop the caliper off and wind back gentley with a small G cramp, dont be tempted to use the disc to lever the piston back !
put the calliper back on loosely put in the old pad or spacer again the calliper on the side thats free, this time put something between the one you have moved and the disc, and push the other one out and repeat.

You can get them reasonably free like this but will take a while, you really need to strip the pistons out and remove the dust seals, where you will find a build up of light white corrosion which makes the dust seals tight on the pistons.Clean out the grooves lightly, clean the pistons, carefull they are aluminium, apply a smidge of red rubber grease and re-assemble.
Once cleaned out you should be able to push the pistons back in with thumb pressure only.
If you have a compressor push the pistons out that way, but be very , very careful, if in any doubt seek professional help as its very easy to loose your fingers, or eye , if not experienced just to save a few bob

 

[Bigtwin]

The easiest and safest way would be to leave the caliper connected to the brake line, put the old pad or suitable spacer on the free side between piston and disc, and slowly apply pressure via the brake lever.

Thought about this, but was worried that if the pots are well seized, it may warp the disc before it moves them?

 

[pomm001]

Thought about this, but was worried that if the pots are well seized, it may warp the disc before it moves them?

If they are that bad, or you are concerned then drop the caliper off,still connected, and put a spacer between two pistons, say a socket, use a cramp on the other one
leaving just the one to be pumped out.
Its also an advantage to have at least two pairs of hands to hold everything too

 

[Possu]

If you've got access to a decent compressor, try this, worked fine for me for years.

Get an old banjo bolt of correct size & drill a hole (4-5mm will do) straight through the bolt head so that the hole runs in to the fluid channel. Weld the appropriate airline fitting to the head of the drilled banjo bolt. Make a spacer out of a 10mm length of ally bar, approx. 15-17mm diameter - this replaces the brake line banjo.

Remove caliper from bike, wrap in a rag & place in a vice. Screw the welded up banjo bolt & spacer in to the caliper, attach airline & let air pressure do it's job. Keep fingers etc out of the way because a seized piston comes out at speed (don't ask how I know this )

If working on a 4-pot caliper, work on one piston at a time. Place a a socket or piece of wood between the remaining two opposed pistons not being currently worked on & clamp the piston opposite the one you're working on with mole grips, G-clamp etc.

Clean piston & inspect seals, lube with brake fluid before refitting. Repeat procedure until the calipers done. May be worth having a new set of seals to hand if they can be bought separately from pistons?

I would post a photo of the welded up banjo bolt & spacer but my home computer is dead at the moment and I can't access my online pics from work.

If someone's got a seized caliper, I'd be willing to have a go at freeing the piston FOC if they want to bring it to Oxford. I unseized a DRZ rear caliper last week, very badly corroded, took a minute or so @ 120psi, piston flew the length of the garage when it finally came out.

Give me a call at home if needed: 01865-463626

Steve