ace calipers overhaul

[blahheed]

anybody taken thunderace calipers pistons out?
any tips on doing it?
____________________
Big

[owl10]

Not thunderace specifically, but several other car / bike calipers.

1st option is with the caliper connected to the bike by the break line.

Remove pads from caliper
Pump brake a few times - see which pistons move.

If they ll move then no problems, pull brake lever until they wont go any further.

If one is seized, then push the 'free' pistons back into the caliper and insert some wood or screwdrivers or something to stop them moving, leaving only the seized piston with anywhere to go.

Try again pulling brake lever to see if it moves, and repeat.

Once its half way out remove all obstructions and get all the other pistons out as far as possible using the pulling brake lever technique.

Then remove caliper, and split.

Find some pliers - wrap electrical tape around the teeth several times so as not to scratch pistons and with a bit of working back and forward you can remove.

Clean up with a very fine grit sandpaper / emery cloth if needed, or replace piston with a new one.


Second option, and suitable if already split, is to use an airline to blow them out - suggest caution as they come out faster than you think - make sure caliper isnt pointing at anything when you do this as chance of injury / damage to bike.
____________________
DanceLikeAMonkey says: "An infinte amount of web pages available
Yet I still end up reading crap like that"

[evoboy]

[blahheed]

i know they don't split now.
looks a bit fiddly,
need something to wiggle the pistons out.

are those inside piston pliers any good?
____________________
Big

[mentalboy]

I did some last year for a mate and they were the most stubborn set of calipers I've ever had the misfortune to strip. All the pots were seized, I could only wonder how the previous owner ever stopped it! They went in the bin as previous tinkerers had scored some of the cylinder walls caused by misuse of grips getting the pots out!
Hope yours are in better nick. If you need to remove the blue stops I have found the cleanest way to do this is with a strip of 4 mm steel, ground to fit into two of the notches. It needs to be a tight fit or you'll just mash the ally stop. ( I have an adjusted coal chisel for the job) then just get a set of large adjustables on it and wind it out - a messier method if you've got no steel to hand is to use the end of a large file, but it does make a mess of the ally!

Edit: wonders if Jivebunny had been near it.
____________________
Make mine a Corona.

[Fizzer Thou]

If the calipers started off looking like these R1 calipers,then give them a good clean externally first,removing the pins,pads and chrome plates

https://i666.photobucket.com/albums/vv23/WiNot_Rhencullen/Workshop/Picture383.jpg

Then pump out the pistons so that they are all about halfway out and almost touching

https://i666.photobucket.com/albums/vv23/WiNot_Rhencullen/Workshop/Picture382.jpg

Try not to let any of the pistons come all of the way out,but note which ones move the most freely and look to remove them last - for a good reason.Push the freely moving ones back into the caliper body and use an old file where the disc normally rotates to stop them moving too far out.Pump out the pistons that are not moving so freely and try and work them so that they both pop out at the same time.Clean the pistons,seals and seal grooves.Once done,reinstall the pistons using only the distortion seals and not the dust seals.Use either compressed air or hydraulic pressure to push out the other pistons,holding back the cleaned pistons.Remove the dirty pistons and seals and clean.Thoroughly clean the caliper body,paying particular attention to road and friction material stuck on the caliper.

https://i666.photobucket.com/albums/vv23/WiNot_Rhencullen/Workshop/Picture384.jpg

Reassemble using either fresh brake fluid (I use DoT4) or red seal grease (ebay).Do not bother to remove the link pipe.

If installing new pads,ensure that the new pads move freely in the caliper.Sometimes excess paint or plating on the pad backplate hinders movement.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'