Caliper refurb

[griston64]

I picked up some old rear calipers which I am going to refurbish

Got them apart ok but I can't get the pistons out. Any tips for removing them ?

I don't have a compressed air thingy

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Cheers

[Chooch84]

Remove the pins which hold the pads and the brake pads, there should be a rubber dust ring that's around the piston, gently remove those, use 2 flat screwdrivers either side of the piston to ease out of it's home. You'll find that once one is out the other should be easier to pop out. Might also help to undo the bleed valve.

[Clan]

Originally Posted by griston64

I picked up some old rear calipers which I am going to refurbish

Got them apart ok but I can't get the pistons out. Any tips for removing them ?

I don't have a compressed air thingy

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Attachment 121895

Attachment 121896

Cheers

Thank goodness you asked , if you had used compressed air you would have a lethal weapon as the piston shoots out like a bullet .. and would probably go through a wooden shed wall or embed itself half way through your body ...
The proper way is to use a grease gun and pump grease through the bleed nipple until it gently expels the piston , you are then able to get the rubber boot out of the inner groove in the bore . You cant get the boot out with the piston in . Likewise fit the boot in the cylinder first then push the piston down through the centre .
I have never had any luck with self refurbished calipers they always stick again in the near future , best get a pair or new ones .

[Chooch84]

Originally Posted by Clan

The proper way is to use a grease gun and pump grease through the bleed nipple until it gently expels the piston , you are then able to get the rubber boot out of the inner groove in the bore . You cant get the boot out with the piston in . Likewise fit the boot in the cylinder first then push the piston down through the centre .
I have never had any luck with self refurbished calipers they always stick again in the near future , best get a pair or new ones .

Grease gun method sounds good...

Dust boots come out if you have a small pick tool and if you use some WD40 to allow them to slip off with some ease, you just need to be careful to not split the rubber.

I replaced the pistons on my rears just as a precaution, 2 years later they're still fine. You just need to be careful when you replace any O-rings, I used red rubber grease during assembly.

Each to their own, some people have good experience some have bad....

[griston64]

Cheers Guys

Got one out but the other side is a bit stuck so going to leave till tomorrow.

I would've thought if you get the right kit to rebuild they should be ok ?

There is also a rubber seal in the bore which I have removed as well ? Thought it would be best to renew all rubber seals O rings and pistons

I was thinking of blasting and repainting as well. Might as well go the whole hog

[bob12]

Yes .... !!! In the past I have used a foot pump on the hydraulic nipple NOT a direct pressure line. Point it away from you and be very gentle, and take it very easily. Bind the whole thing very well in old toweling on something substantial as if they 'popped' without any constraint a free piston is a lethal weapon!!

[tofufi]

Originally Posted by Clan

Thank goodness you asked , if you had used compressed air you would have a lethal weapon as the piston shoots out like a bullet .. and would probably go through a wooden shed wall or embed itself half way through your body ...

I have never had any luck with self refurbished calipers they always stick again in the near future , best get a pair or new ones .

I've always used compressed air on twin piston calipers like these (rears) - the piston can't go very far as it will only go into the caliper. On the 700 fronts it has potential to do rather more damage

I rebuilt the calipers on my (45 year old) van 7 years ago, no binding or sticking since. I didn't use any grease on them either...

[Laird Scooby]

If you media blast them Mark, use old bolts to blank off the bolt holes for the bleed nipples and fluid inlets. Also pack the bores where the pistons go with cotton wool or similar then plasticine or similar to seal the wadding in and protect the exposed end of the bore - likewise with the fluid transger holes if you split the caliper in to halves.

If you do split it, you can use a polishing mop on a Dremel or similar with a cotton mop and something like rubbing compound then Solvol Autosol to firstly smooth then polish the bore to a mirror finish.

https://www.halfords.com/motoring/pa...bbing-compound

I used this method on the front knuckles when replacing wheel bearings on my other beast some time back, likewise with the bottom ball joints on the same car. Made life much easier for inserting both!

Once you've polsihed the bores, give the pistons the same treatment obviously on the outside although you can do the inside if you like!

A bit of silicone grease or red rubber grease will aid reassembly with the rubber components, i'd suggest filling the caliper with brake fluid once you've done the piston/cylinder areas and seal them up after if possible but that may not be possible or practical.

Knowing your skills and attention to details i'm sure you won't have any problems. What colour are you planning on painting them after blasting?

[WUMPSTER]

tbh the cost of professionally refurbished calipers against diy in safety terms it has to be professionally done ones every time its brakes dont mess about with your own life or the life of others with such important parts of a car

[360beast]

I refurbished the callipers on my Fabia when I upgraded to bigger Octavia VRS 312mm ones. And refurbing callipers on Bentley Arnages is part of the service schedule.

I have always used compressed air to remove the piston by putting a block of wood between the piston and the caliper, I remove the wood and put a smaller piece in as the piston comes out until eventually when it does pop it can only move a couple mm and because it has been done slowly it doesn’t shoot out. I have seen the grease gun method but to me personally covering the caliper inside with grease just means extra cleaning. Obviously as you don’t have a compressor Mark you can’t do this so the grease gun method will be best.