10 replies to this topic

[flatline]

Standard AP calipers for 8.4 discs.

I want to refurbish them,repaint,news seals ect but cant find a "how to"

I had a look in the frequently asked questions but couldn't see a guide.

Any help appreciated :)

[bluesprite]

I want to give this a go too and was wondering what's the best way to lose as little brake fluid as possible? And not let air into the system or is that inevitable if you take the caliper off?

[bmcecosse]

Put a plastic bag over the filler neck of the reservoir -and refit the cap. Also - have a dummy blank fitting ready to fit to the pipe end when you unscrew the caliper......

[AndyR]

I did this on my 4 pots, but guess its pretty much the same - minus 2 pots!

Here goes....

Clamp the brake hoses (if you plan on keeping the old fluid) - would suggest clamping then draining and putting new fluid in

Once the calipers are off the car you can start removing any of the old paint and or rust - would do this first to avoid getting any dirt behind the pistons etc

Once cleaned up and painted with high temp brake caliper paint (from halfords etc) you can move on to removing the pistons

I did this by using a short piece of copper brake pipe with the correct fitting on one side and any fitting on the other. Connect the fitting to the caliper and let the other slip down the tube, then use a bicycle pump with a presta valve and press the flanged part of the tube into the valve - and lock down. This allows you to put some light pressure into the caliper to remove the pistons - be careful as the pressure can get very high if the pistons are a little tight. One will come out leaving the other in, then the line to that piston will be open so the pressure wont get the other out. Put the one that has just come out in a little bit (enough so you can remove it with your fingers) then put a wood clamp in to stop it from coming out when you pump up to get the other out - you can then just lift the other out with your fingers.

Go ahead a remove the old seals from the calipers with a small flat head screw driver - be careful not to damage the seal area.

Make sure the piston chamber is clean and then you can start putting new seals and pistons in - would always replace the pistons with stainless ones when replacing the seals.

I used some brake caliper lubricant to get the seals and pistons in - others will probably not agree with this but you can use new brake fluid also.

Then go ahead with putting the main seal in - like so  IMG_2073.jpg   316.13K   33 downloads and  IMG_2074.jpg   309.2K   17 downloads

Then place the wiper seal in the carrier and lube it up a bit, or you could use some brake fluid i guess
 IMG_2075.jpg   339.93K   18 downloads
i used this
 IMG_2076.jpg   364.28K   24 downloads
like this
 IMG_2077.jpg   288.09K   13 downloads

Then gently place the seal in the caliper
 IMG_2080.jpg   289.23K   26 downloads

I used a flat piece of hard wood the width of the seal to place even pressure over the seal and press it into the caliper evenly - this is the hardest part and if i were you would order a spare set of seals as you will no doubt damage the first few practicing. But this worked the best and worked everytime
 IMG_2079.jpg   369.96K   19 downloads
Do this for all (obviously)

If you want to you could then also go around and replace the bleed nipples

Reconnect to your brake lines and rebleed the system.

Fewwww - hopefully i havnt left anything out. Its fairly straight forward just take your time and keep your work area as clean as possible

Good luck

Andy

[AndyR]

Forgot to add that you then need to put the pistons in before you connect them back to the car

Andy

[bmcecosse]

Good explanation above - except I have never found air pressure do any good. I had to use my grease gun - which fortunately has the correct 3/8" UNF thread - to force the pistons out. Took a LOT opf hard pumping. Obviously then - need to clean ALL the grease out.......

[flatline]

Thanks for taking the time with the pics and explanation :)

If im replacing all the seals and pistons will nitromors do a good job on paint removal? Ive used it on other stuff but not calipers.


Are these the right parts for a rebuild?

http://www.minispare...pid=33290=

http://www.minispare...pid=36890=

http://www.minispare...pid=34891=

http://www.minispare...pid=36980=

Edited by flatline, 13 February 2012 - 12:54 AM.

[AndyR]

No probs - thought taking some pics would come in handy at some point. Shouldnt see a problem with using it. Not sure how it will respond to high temp paint but worth giving it a bash.

You links dont seem to be working, try linking them outside your basket.

Andy

[flatline]

The notromors got rid of most of it but i blasted the rest with some aluminium oxide ,ill post some pics if i can find the camera.Will i need to primer them now they are bare?
Also got the pistons out and they look fine so not sure ill change them,same with the main bolts.

oring - http://www.minispare...pid=36890=

Caliper seals - http://www.minispare...pid=34891=

Piston - http://www.minispare...pid=33290=

Bleed nipple - http://www.minispare...pid=36980=

Discs - http://www.minispare...pid=35071=

Hose - http://www.minispare...pid=34809=

Cheers again :)

[flatline]

Dont know whats going on with the links because i dont have anything in my basket and i cant seem to edit my posts

[AndyR]

These are the minispares part numbers

GRK5008 - Seal Kit
3H2428 - Bleed Nipple
114713 - Stainless Piston
17H7679 - O-ring

For piece of mind i would fit new stainless pistons but if you think yours look ok then its up to you. You shouldnt need to primer the high temp paint, if you are going to you will need high temp primer also - ive always just put the paint to bare metal with no problems. Light first coat then two thicker coats is usually sufficient.

Andy